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Time of Implantation of the Conceptus and Loss of Pregnancy
Abstract
Implantation of the conceptus is a key step in pregnancy, but little is known about the time of implantation or the relation between the time of implantation and the outcome of pregnancy.
We collected daily urine samples for up to six months from 221 women attempting to conceive after ceasing to use contraception. Ovulation was identified on the basis of the ratio of urinary estrogen metabolites to progesterone metabolites, which changes rapidly with luteinization of the ovarian follicle. The time of implantation was defined by the appearance of chorionic gonadotropin in maternal urine.
There were 199 conceptions, for 95 percent of which (189) we had sufficient data for analysis. Of these 189 pregnancies, 141 (75 percent) lasted at least six weeks past the last menstrual period, and the remaining 48 pregnancies (25 percent) ended in early loss. Among the pregnancies that lasted six weeks or more, the first appearance of chorionic gonadotropin occurred 6 to 12 days after ovulation; 118 women (84 percent) had implantation on day 8, 9, or 10. The risk of early pregnancy loss increased with later implantation (P<0.001). Among the 102 conceptuses that implanted by the ninth day, 13 percent ended in early loss. This proportion rose to 26 percent with implantation on day 10, to 52 percent on day 11, and to 82 percent after day 11.
In most successful human pregnancies, the conceptus implants 8 to 10 days after ovulation. The risk of early pregnancy loss increases with later implantation.
... Thus, extended progesterone administration before transfer is recommended (45). Implantation after the normal endometrial receptivity period is closely associated with early pregnancy loss (46). A prolonged window of endometrial receptivity may account for the delayed implantation of severely damaged embryos and the subsequent early pregnancy loss (47). ...
... A higher incidence of early pregnancy loss was not detected in between group P3, which was administered progesterone for 3 days, and P4, which was administered progesterone for 4 days before transferring vitrified-warmed embryos at the third day cleavage stage, This was not observed in either group P5, which was administered progesterone for 5 days, or P6, which was administered progesterone for 6 days before transferring vitrified-thawed blastocysts, which may be because the duration of progesterone administration was no shorter than the age of the embryo (42). According to these data, there may also be no difference in the rate of early pregnancy loss between the two groups with or without prolonged progesterone administration, which may be due to adaptation to the normal period of endometrial receptivity (46). In contrast, Day 3 embryos of group P4 were transferred on the fifth day of progesterone supplementation, and blastocysts of group P6 were transferred on the seventh day of progesterone supplementation, which might have been too long, although no evidence exists that longer progesterone supplementation had a negative impact on success rates (43). ...
Objective
The administration of progesterone before transfer in hormone replacement treatment (HRT) is crucial for the clinical outcomes of frozen-thawed embryo transfer (FET), but the optimal duration of progesterone remains controversial. This study aimed to investigate the effect of the duration of progesterone administration on the clinical outcomes of FET cycles.
Methods
This prospective cohort study included 353 artificial FET cycles conducted at a reproductive medicine center between April and October 2021. The FET cycles were stratified into four groups based on the duration of progesterone supplementation before the procedure and the embryonic development stage: group P3 (73 patients) received intramuscular progesterone for 3 days and group P4 (87 patients) for 4 days before Day 3 frozen embryo transfer, group P5 (70 patients) for 5 days and group P6 (123 patients) for 6 days before frozen blastocyst transfer. This trial was performed using one or two vitrified embryo(s) when the endometrial thickness reached 7 mm after estrogen supplementation in an artificial cycle. The primary outcome was clinical pregnancy, and secondary outcomes included biochemical pregnancy, implantation, early pregnancy loss, and live births.
Results
There were no significant differences in the demographic and clinical characteristics between the groups. No significant difference was observed in the clinical pregnancy rates between groups: 23/73 (31.5%) in group P3 vs 28/87 (32.2%) in group P4 ( P = 0.927). Compared to group P5 (41/70, 58.6%), the clinical pregnancy rate was not significantly different in group P6 (77/123, 62.6%, P = 0.753). There was no significant difference in the implantation rates between groups: 33/136 (24.3%) in group P3 vs 34/166 (20.5%) in group P4 ( P = 0.431), and 62/133 (46.6%) in group P5 vs 107/231 (46.3%) in group P6 ( P = 0.956). The duration of progesterone supplementation (mean: 3.5 ± 0.5 days; range:3–4 days) before Day 3 frozen embryo transfer did not impact clinical pregnancy (odds ratio [OR] 1.048; 95% confidence interval [CI], 0.518–2.119). The duration of progesterone administration (mean: 5.6 ± 0.5 days; range:5–6 days) before frozen blastocyst transfer may not affect clinical pregnancy (OR 1.339; 95% CI, 0.717–2.497).
Conclusion
There may be no significant correlation between the duration of progesterone supplementation and pregnancy outcomes in artificial FET cycles, although the clinical pregnancy rate was higher when progesterone supplementation was extended for one day before FET.
... In humans, fecundability is poor (20-25%), and approximately 75-80% of pregnancy failures result from implantation failure [1]. The human endometrium undergoes dynamic changes, with menstrual breakdown and subsequent regeneration during each menstrual cycle [2]. Intricate changes at the tissue, cellular, and molecular levels during each menstrual cycle are required to create a period of receptivity for blastocyst implantation [3,4]. ...
... This period of receptivity is known as the "window of implantation (WOI)", a term first used by Edwards to describe the human uterus [5]. The WOI is a short period that begins on day 19 or 20 of the menstrual cycle and persists for 4-5 days [2,6]. ...
Objective:
This study aimed to evaluate the endometrial transcriptomic patterns in the early secretory phase (ESP) and mid-secretory phase (MSP) of the natural menstrual cycle before in vitro fertilization and embryo transfer (IVF-ET).
Methods:
Thirty patients whose endometrial tissues were obtained from the ESP or MSP of a natural menstrual cycle immediately before IVF-ET were included. Endometrial dating was histologically confirmed as ESP (cycle days 16-18) or MSP (cycle days 19-21), according to the noyes criteria. The patients were divided into two groups depending on the IVF-ET outcome: pregnant (n=14; 7 in ESP and 7 in MSP) or non-pregnant (n=16; 8 in ESP and 8 in MSP). Differentially expressed genes (DEGs) in the MSP, compared to the ESP, were identified using NanoString nCounter (COMPANY, CITY, STATE, COUNTRY) data for both the pregnant and non-pregnant groups.
Results:
Thirteen DEGs in the pregnant group and 11 DEGs in the non-pregnant group were identified in the MSP compared to those in the ESP. In both groups, ADRA2A, IRAK2, ADAMTS15, SERPINE1, ITGB3, TMEM252, HAP1, CDCD4A, and ITGA2 were upregulated in the MSP, compared to the ESP. TMEM37, GLB1L2, RND3, and CYP24A1 were upregulated in the MSP only in the pregnant group. ADAMTS8 was downregulated and monoamine oxidase A (MAOA) was upregulated in the MSP only in the non-pregnant group.
Conclusion:
Transcriptomic patterns in the endometrium immediately before IVF-ET appear to differ according to the IVF-ET outcome. These novel DEGs, which have not been previously studied, may have functional significance during the window of implantation and serve as potential biomarkers of endometrial receptivity.
... The dynamic change of endometrial tissue to sex steroid hormones is a complex process that is controlled by the interactions of various cell types, including epithelial, stromal, endothelial, and immune cells in the endometrium (Critchley et al., 2020). During the secretory phase following ovulation, the human endometrium transforms into a narrow window of receptive status to accept the embryo, which is called the window of implantation (WOI) (Wilcox et al., 1999). The scRNA-seq studies showed that the human WOI opens rapidly with a discontinuous transcriptomic activation in the epithelial cells, and this event is accompanied with a widespread decidualization change in the stromal fibroblasts (Wang et al., 2020). ...
... Studies using various animal models have demonstrated that a defective implantation process can create detrimental effects that result in poor pregnancy outcomes (Cha et al., 2012). In humans, the window of uterine receptivity is crucial for successful conception, and any implantation beyond this window leads to spontaneous abortion (Wilcox et al., 1999). Multiple risk factors have been proposed for recurrent implantation failure, including advanced maternal age, smoking, elevated body mass index, stress, endocrine disorders, and embryonic abnormalities (e.g., aneuploidy) [for reviews, see (Bashiri et al., 2018;Ma et al., 2022)]. ...
Early pregnancy is a complex and well-orchestrated differentiation process that involves all the cellular elements of the fetal-maternal interface. Aberrant trophoblast-decidual interactions can lead to miscarriage and disorders that occur later in pregnancy, including preeclampsia, intrauterine fetal growth restriction, and preterm labor. A great deal of research on the regulation of implantation and placentation has been performed in a wide range of species. However, there is significant species variation regarding trophoblast differentiation as well as decidual-specific gene expression and regulation. Most of the relevant information has been obtained from studies using mouse models. A comprehensive understanding of the physiology and pathology of human implantation and placentation has only recently been obtained because of emerging advanced technologies. With the derivation of human trophoblast stem cells, 3D-organoid cultures, and single-cell analyses of differentiated cells, cell type-specific transcript profiles and functions were generated, and each exhibited a unique signature. Additionally, through integrative transcriptomic information, researchers can uncover the cellular dysfunction of embryonic and placental cells in peri-implantation embryos and the early pathological placenta. In fact, the clinical utility of fetal-maternal cellular trafficking has been applied for the noninvasive prenatal diagnosis of aneuploidies and the prediction of pregnancy complications. Furthermore, recent studies have proposed a viable path toward the development of therapeutic strategies targeting placenta-enriched molecules for placental dysfunction and diseases.
... Once the embryo embeds in the endometrium, human chorionic gonadotrophin (hCG) rises in maternal blood and urine, thus allowing for robust estimates of the incidence of pregnancy loss. There is remarkable agreement among many studies that one in three embryos perish after implantation (Wilcox et al., 1999;Wang et al., 2003;Foo et al., 2020;Zinaman et al., 1996). More than half of pregnancy losses occur so early that they escape detection with little or no discernible impact on maternal reproductive fitness beyond increasing the likelihood of conception in subsequent cycles (Wang et al., 2003). ...
... In an experimental primate model, menstruation becomes unavoidable if progesterone is withdrawn for 36 h or longer (Slayden and Brenner, 2006). In humans, the incidence of early pregnancy loss increases exponentially with each day that implantation is delayed beyond the midluteal implantation window (Wilcox et al., 1999). ...
Embryo implantation in humans is interstitial, meaning the entire conceptus embeds in the endometrium before the placental trophoblast invades beyond the uterine mucosa into the underlying inner myometrium. Once implanted, embryo survival pivots on the transformation of the endometrium into an anti-inflammatory placental bed, termed decidua, under homeostatic control of uterine natural killer cells. Here, we examine the evolutionary context of embryo implantation and elaborate on uterine remodelling before and after conception in humans. We also discuss the interactions between the embryo and the decidualising endometrium that regulate interstitial implantation and determine embryo fitness. Together, this Review highlights the precarious but adaptable nature of the implantation process.
... They showed that using hormonally and histologically defined cycles, viable conception occurs only on days 17-19, while no conception occurred in transfers performed before day 17 and after day 19. This observation is consistent with another report that the most successful pregnancies implant 8-10 days after ovulation [36]. The period of embryo implantation, now designated the window of implantation, is said to involve paracrine crosstalk between the decidual fibroblasts and immune cells of the luteal phase endometrium, with the invading placental trophoblasts. ...
... The period of embryo implantation, now designated the window of implantation, is said to involve paracrine crosstalk between the decidual fibroblasts and immune cells of the luteal phase endometrium, with the invading placental trophoblasts. Miscommunication between these factors during implantation is likely to lead to miscarriage or poor pregnancy outcome [36]. During this time, a functional ligand-receptor system develops in the endometrium characterized by upregulation of selectin oligosaccharidebased ligands, while the trophoblasts express L-selectin, which would suggest that trophoblast L-selectin-mediated interactions within the uterus may be critical to establishing human pregnancy [37]. ...
Both uterine endometrium and embryo contribute to implantation success. However, their relative role in the implantation success is still a matter for debate, as are the roles of endometrial receptivity analysis (ERA), endometrial scratch (ES), endometrial microbiome, and intrauterine or intravenous measures that are currently advocated to improve the implantation success. There is insufficient evidence to suggest that the endometrium is more important than the embryo in determining the implantation success and the utility of these measures, especially when euploid embryos are transferred is limited. Although embryo implantation on epithelium other than the endometrium is a very rare event, evidence suggests that embryo implantation and growth is not limited to the endometrium alone. Embryos can implant and develop to result in livebirths on epithelium that lacks the typical endometrial development present at implantation. Currently, the role of embryo euploidy in implantation success is underappreciated. At a minimum, it is the author's opinion that until robust, definitive studies are conducted that demonstrate benefit, reproductive endocrinologists and infertility specialist should be prudent in the way they counsel patients about the utility of ERA, ES, and other measures in improving implantation success.
... Endometrial receptivity is a complex course of events in which the endometrium becomes favourable for embryo implantation under the action of ovarian steroid hormones, during the mid-luteal phase of the ovarian cycle in healthy fertile women [22,23]. Nearly a decade of investigations on the transcriptomic analysis on endometrial receptivity has revealed a comparable difference in the endometrial gene expression profile during the ...
... Endometrial receptivity is a complex course of events in which the endometrium becomes favourable for embryo implantation under the action of ovarian steroid hormones, during the mid-luteal phase of the ovarian cycle in healthy fertile women [22,23]. Nearly a decade of investigations on the transcriptomic analysis on endometrial receptivity has revealed a comparable difference in the endometrial gene expression profile during the early to mid-luteal phases of the window of implantation (WOI) in fertile women [24]. ...
Overlapping disease aetiologies associated with multiple altered biological processes have been identified that change the endometrial function leading to recurrent implantation failure (RIF) and recurrent early pregnancy loss (REPL). We aimed to provide a detailed insight into the nature of the biological malfunction and related pathways of differentially expressed genes in RIF and REPL. Endometrial biopsies were obtained from 9 women experiencing RIF, REPL and control groups. Affymetrix microarray analysis was performed to measure the gene expression level of the endometrial biopsies. Unsupervised clustering of endometrial samples shows scattered distribution of gene expression between the RIF, REPL and control groups. 2556 and 1174 genes (p value < 0.05, Fold change > 1.2) were significantly altered in the endometria of RIF and REPL patients’ group, respectively compared to the control group. Downregulation in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the differentially expressed genes (DEGs) in RIF and REPL including ribosome and oxidative phosphorylation pathways. Gene Ontology (GO) analysis revealed ribosomes and mitochondria inner membrane as the most significantly downregulated cellular component (CC) affected in RIF and REPL. Determination of the dysregulated genes and related biological pathways in RIF and REPL will be key in understanding their molecular pathology and of major importance in addressing diagnosis, prognosis, and treatment issues
... However, ER is a complicated process that allows embryonic attachment, invasion, and development. The endometrium is unique in its ability to prevent embryos from implanting, except during the window of implantation (WOI) (9). The optimal WOI has been determined to be not consistent among all women (10). ...
... The optimal WOI has been determined to be not consistent among all women (10). Implantation failure is more common in women who have WOI displacement, which may delay, advance, or narrow the WOI due to unknown contributing variables that disturb the ER (9,(11)(12)(13). Considering the high treatment costs and the potential effects on female emotions, more accurate determination of the optimal WOI is needed for improving clinical pregnancy outcomes (14,15). ...
Background:
A successful pregnancy using in vitro fertilization and embryo transfer (IVF-ET) requires a receptive endometrium, good-quality embryos, and a synchronized embryo-endometrial dialogue. Although embryo quality and endometrial receptivity (ER) have been fully assessed to exclude substandard conditions, the probability of successful ET is relatively low. Currently, embryo-endometrial synchrony is considered to be a possible explanation, because delayed, advanced, or narrowed window of implantation (WOI) may lead to ET failure.
Objective:
This study aims to establish a nomogram incorporating a series of ultrasonic ER markers on the day before implantation to assess the embryo-endometrial synchrony, which may contribute to the improvement of clinical pregnancy outcomes.
Methods:
Totally 583 women with 1135 complete IVF cycles were retrospectively analyzed. Among them, 357 women with 698 cycles and 226 women with 437 cycles were assigned to the training and validation cohorts, respectively. Ultrasonic ER markers obtained on the day before implantation were collected for analyses. In the training cohort, the screened correlates of clinical pregnancy failure were utilized to develop a nomogram for determining whether an infertile woman is suitable for the ET next day. This model was validated both in the training and validation cohorts.
Results:
Spiral artery (SA) resistance index (RI), vascularisation index (VI), and flow index (FI) were independently associated with the ET failure (all P < 0.05). They were served as the components of the developed nomogram to visualize the likelihood of implantation failure in IVF-ET. This model was validated to present good discrimination and calibration, and obtained clinical net benefits both in the training and validation cohorts.
Conclusion:
We developed a nomogram that included SA-RI, VI, and FI on the day before implantation. It may assist physicians to identify patients with displaced WOI, thus avoiding meaningless ET prior to implantation.
... Although it is known that stress can influence female reproduction, how stress affects embryo development is not very clear. Because there are reports that the early stages of pregnancy are more sensitive to stress than the later stages are [1,2], the preimplantation period is envisioned as one of the most stress-vulnerable phases [3,4]. However, reports on the effects of female stress on preimplantation embryos are very limited. ...
... The culture medium used for oocyte maturation was TCM-199 (Gibco, Grand Island, NY, USA) containing 10% porcine follicle fluid, 0.1% PVP, 0.91 mM sodium pyruvate, 3.05 mM glucose, 0.05 IU/mL FSH, 10 ng/mL EGF, 0.05 IU/mL LH, 0.57 mM cysteine, 50 µg/mL streptomycin and 100 IU/mL penicillin. ...
Previous studies show that stressful events after ovulation in sows significantly impaired the embryo cleavage with a significant elevation of blood cortisol. However, the effects of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol on fertilization and embryo development remain to be specified, and whether they damage pig embryos directly or indirectly is unclear. This study demonstrated that embryo development was unaffected when pig parthenotes were cultured with different concentrations of CRH/ACTH/cortisol. However, embryo development was significantly impaired when the embryos were cocultured with pig oviductal epithelial cells (OECs) in the presence of CRH/cortisol or cultured in medium that was conditioned with CRH/cortisol-pretreated OECs (CRH/cortisol-CM). Fertilization in CRH/cortisol-CM significantly increased the rates of polyspermy. CRH and cortisol induced apoptosis of OECs through FAS and TNFα signaling. The apoptotic OECs produced less growth factors but more FASL and TNFα, which induced apoptosis in embryos. Pig embryos were not sensitive to CRH because they expressed no CRH receptor but the CRH-binding protein, and they were tolerant to cortisol because they expressed more 11-beta hydroxysteroid dehydrogenase 2 (HSD11B2) than HSD11B1. When used at a stress-induced physiological concentration, while culture with either CRH or cortisol alone showed no effect, culture with both significantly increased apoptosis in OECs. In conclusion, CRH and cortisol impair pig fertilization and preimplantation embryo development indirectly by inducing OEC apoptosis via the activation of the FAS and TNFα systems. ACTH did not show any detrimental effect on pig embryos, nor OECs.
... α-Tocopherol deficiency also caused morphological changes at very early stages in development (Head et al., 2020, Head et al., 2021, which occur prior to an analogous time to when a woman knows she is pregnant. α-Tocopherol protects the developing nervous system of zebrafish and rodents during the time frame in which neural tube defects occur in human embryos (18-19 hpf in zebrafish (Kimmel et al., 1995), 9-12 days in rats (Altman andKatz, 1962) and 22-30 days in humans (Gilbert, 2010, O'Rahilly, 1979, Wilcox et al., 1999. ...
This is a narrative review of the evidence of α-tocopherol importance in human health, especially with regards to its vitamin role. α-Tocopherol is a potent peroxyl radical scavenger and this role is prominent in its efficacy in maintaining the metabolic health of tissues. Vitamin E deficiency is discussed as a tool to understand the impact of α-tocopherol’s absence promoting increased lipid peroxidation and polyunsaturated fatty acid depletion. Downstream deficiency consequences include impacts on choline and one carbon metabolism, glucose and energy metabolism, and their interactions with critical thiols, such as glutathione. Importantly, human vitamin E deficiency, caused by genetic defects in the α-tocopherol transfer protein (α-TTP) provides important clues for the necessity of α-tocopherol for the peripheral nervous system. Moreover, α-TTP expression in the liver, brain, eyes, and placenta illustrates that these tissues are especially vulnerable and require this specific α-tocopherol delivery mechanism for their protection. Although clinical trial evidence is limited and equivocal about the health benefits of vitamin E supplements, there is epidemiologic evidence of the long-term benefits of increased α-tocopherol intakes in “healthy” diets (high in vegetables and fruits, fish, nuts, and seeds, as well as fiber). The elaborate regulation of α-tocopherol concentrations by the human body suggests that the consistent consumption of the recommended amounts of dietary α-tocopherol (15 mg) over a lifetime are protective of the at-risk tissues, as well as providing protection from chronic diseases.
... Both previously mentioned meta-analyses (Martins et al., 2011;Lacey et al., 2021) reported no difference between the assisted hatching and control groups concerning miscarriage rate both in the unselected group as in the subgroup of participants with or without previous failed IVF or ICSI attempts. Evidence was reported that implantation beyond the endometrial receptivity window resulted in increased miscarriage rates (Wilcox et al., 1999). It is therefore hypothesized that assisted hatching may provide a more optimal synchronization between endometrial receptivity and implantation. ...
Study question:
Does assisted hatching increase the cumulative live birth rate in subfertile couples with repeated implantation failure?
Summary answer:
This study showed no evidence of effect for assisted hatching as an add-on in subfertile couples with repeated implantation failure.
What is known already:
The efficacy of assisted hatching, with regard to the live birth rate has not been convincingly demonstrated in randomized trials nor meta-analyses. It is suggested though that especially poor prognosis women, e.g. women with repeated implantation failure, might benefit most from assisted hatching.
Study design, size, duration:
The study was designed as a double-blinded, multicentre randomized controlled superiority trial. In order to demonstrate a statistically significant absolute increase in live birth rate of 10% after assisted hatching, 294 participants needed to be included per treatment arm, being a total of 588 subfertile couples. Participants were included and randomized from November 2012 until November 2017, 297 were allocated to the assisted hatching arm of the study and 295 to the control arm. Block randomization in blocks of 20 participants was applied and randomization was concealed from participants, treating physicians, and laboratory staff involved in the embryo transfer procedure. Ovarian hyperstimulation, oocyte retrieval, laboratory procedures, embryo selection for transfer and cryopreservation, the transfer itself, and luteal support were performed according to local protocols and were identical in both the intervention and control arm of the study with the exception of the assisted hatching procedure which was only performed in the intervention group. The laboratory staff performing the assisted hatching procedure was not involved in the embryo transfer itself.
Participants/materials, setting, methods:
Participants were eligible for inclusion in the study after having had either at least two consecutive fresh IVF or ICSI embryo transfers, including the transfer of frozen and thawed embryos originating from those fresh cycles, and which did not result in a pregnancy or as having had at least one fresh IVF or ICSI transfer and at least two frozen embryo transfers with embryos originating from that fresh cycle which did not result in a pregnancy. The study was performed at the laboratory sites of three tertiary referral hospitals and two university medical centres in the Netherlands.
Main results and the role of chance:
The cumulative live birth rate per started cycle, including the transfer of fresh and subsequent frozen/thawed embryos if applicable, resulted in 77 live births in the assisted hatching group (n = 297, 25.9%) and 68 live births in the control group (n = 295, 23.1%). This proved to be statistically not significantly different (relative risk: 1.125, 95% CI: 0.847 to 1.494, P = 0.416).
Limitations, reasons for caution:
There was a small cohort of subfertile couples that after not achieving an ongoing pregnancy, still had cryopreserved embryos in storage at the endpoint of the trial, i.e. 1 year after the last randomization. It cannot be excluded that the future transfer of these frozen/thawed embryos increases the cumulative live birth rate in either or both study arms. Next, at the start of this study, there was no international consensus on the definition of repeated implantation failure. Therefore, it cannot be excluded that assisted hatching might be effective in higher order repeated implantation failures.
Wider implications of the findings:
This study demonstrated no evidence of a statistically significant effect for assisted hatching by increasing live birth rates in subfertile couples with repeated implantation failure, i.e. the couples which, based on meta-analyses, are suggested to benefit most from assisted hatching. It is therefore suggested that assisted hatching should only be offered if information on the absence of evidence of effect is provided, at no extra costs and preferably only in the setting of a clinical trial taking cost-effectiveness into account.
Study funding/competing interest(s):
None.
Trial registration number:
Netherlands Trial Register (NTR 3387, NL 3235, https://www.clinicaltrialregister.nl/nl/trial/26138).
Trial registration date:
6 April 2012.
Date of first patient’s enrolment:
28 November 2012.
... In our sample, 935 (corresponding to 38%) become teenage mothers in a later pregnancy and 1770 11 However, there are some inherent problems of under-and misreporting that cannot be avoided, even in registry data and under universal health coverage. Studies show that 15-20% of clinically recognized pregnancies end as a miscarriage, while a similar number are miscarried pre-clinically (Munk-Olsen et al., 2014;Wilcox et al., 1999). The number of unrecognized early miscarriages is even higher for teenagers (Lang & Nuevo-Chiquero, 2012). ...
This paper investigates whether delaying motherhood beyond the teenage years benefits children. We account for selection into teenage motherhood in two parallel ways: We compare children with their cousins and we exploit miscarriages as a natural experiment that induces some women to postpone childbirth. Across the two strategies, we find no or limited effects of teenage motherhood on children’s health and educational outcomes. When we use women delaying motherhood to their early twenties as a counterfactual for teenage mothers, we show suggestive evidence that the effects of such delays are nil across outcomes for both strategies.
... The synchronicity of a good-quality embryo and a receptive endometrium is essential to achieve pregnancy [11]. The progesterone secreted from the ovaries is required for the endometrium to be receptive. ...
Purpose
To predict ovulation in subfertile women using serial follicular growth (FG) and serum hormone measures (estradiol (E2), luteinizing hormone (LH), and progesterone (P) levels) in mathematical models.
Methods
This was a prospective observational study of 116 subfertile women aged between 18 and 40 years. FG was assessed by serial transvaginal ultrasonography starting from cycle days 8–12, depending on cycle length. Once the dominant follicle reached 15–16 mm, hormone levels were assessed daily. The primary outcome measure was ovulation (Ov), with a serum LH level ≥15 IU/l defining the start of the LH surge (the day prior to ovulation) and a serum P level >1 μg/ml concurrent with a drop in serum E2 levels indicating Ov. To determine Ov, mathematical models were generated using FG, LH, E2, and P measurements.
Results
A mathematical model was constructed using exponential regression to relate days until and after ovulation with P levels. The Ov(P) model was found to be superior to the Ov(LH) model in the prediction of Ov, with high R2 and low RMSE values of 0.9983 and 0.2454, respectively. In the range of [−2, 2] days, the net accuracy of the Ov(P) model was 63.0%, while with an allowed one-day error, the accuracy was 99.6%.
Conclusion
Serum P levels display a highly predictable linear curve in natural cycles, which enables the prediction of ovulation. The Ov(P) model can be independently used to schedule embryo transfer in natural frozen-thaw cycles and could therefore replace the Ov(LH) model in clinical practice.
... The absence of corpus luteum (CL) in HRT makes the duration of P before transfer crucial to the outcomes of pregnancy in FET cycles. It is well recognized that inappropriate P duration before transfer can result in an out-of-sync endometrium and embryo, leading to early pregnancy loss [44]. However, evidence demonstrates that pregnancies can occur after very short progesterone supplementation, indicating that a short duration of P supplementation before FET is sufficient to create a receptive endometrium [45,46]. ...
Over the past decade, the application of frozen-thawed embryo transfer treatment cycles has increased substantially. Hormone replacement therapy and the natural cycle are two popular methods for preparing the endometrium. Hormone replacement therapy is now used at the discretion of the doctors because it is easy to coordinate the timing of embryo thawing and transfer with the schedules of the in-vitro fertilization lab, the treating doctors, and the patient. However, current results suggest that establishing a pregnancy in the absence of a corpus luteum as a result of anovulation may pose significant maternal and fetal risks. Therefore, a ‘back to nature’ approach that advocates an expanded use of natural cycle FET in ovulatory women has been suggested. Currently, there is increasing interest in how the method of endometrial preparation may influence frozen embryo transfer outcomes specifically, especially when it comes to details such as different types of ovulation monitoring and different luteal support in natural cycles, and the ideal exogenous hormone administration route as well as the endocrine monitoring in hormone replacement cycles. In addition to improving implantation rates and ensuring the safety of the fetus, addressing these points will allow for individualized endometrial preparation, also as few cycles as possible would be canceled.
... Progesterone is essential in this process for the establishment of the endometrial receptivity [8]. However, endometrial receptivity exists only for a short period of time and a successful implantation depends on a synchrony between the development of a receptive endometrium and the embryo [9]. ...
Purpose
Displaced endometrial receptivity has been discussed as a possible cause of recurrent implantation failure in patients undergoing assisted reproductive technology. The aim of this study was to document our experience with the endometrial receptivity analysis in patients with recurrent implantation failure.
Methods
This retrospective cohort study, conducted at the Fertility Centre of the University Hospital, Duesseldorf Germany, presents the results of the endometrial receptivity analysis in 67 patients with recurrent implantation failure and compares the clinical outcome between these 67 patients who underwent a personalized frozen-thawed embryo transfer guided by the results of the endometrial receptivity analysis and 32 patients with recurrent implantation failure who performed a standardized frozen-thawed embryo transfer.
Results
The data analysis revealed a displaced endometrial receptivity in 73% (49/67) of all tested patients. Out of these patients, 24% (12/49) were early receptive, 74% (36/49) were pre-receptive, and 2% (1/49) were post-receptive. Comparison of pregnancy rate, clinical pregnancy rate, and live-birth rate between personalized (49%, 39%, 27%, respectively) and standardized embryo transfer (44%, 31%, 19%, respectively) reveals no statistically significant difference. In both groups, patients had an average of four unsuccessful embryo transfers.
Conclusion
In this cohort of patients with recurrent implantation failure, the endometrial receptivity analysis showed a high incidence of displaced endometrial receptivity. However, a personalized embryo transfer did not increase reproductive outcome. Displaced endometrial receptivity might not be the main cause for recurrent implantation failure in this cohort.
... Typical HR protocols use progesterone supplementation for the equivalent number of days before transfer as the stage of development of the embryo is transferred (ie. 5 days for a day 5 blastocyst) (6). Pregnancy rates are lower, and the risk of early pregnancy loss is higher when transfer and implantation occur after greater than 6 days of progesterone administration for a day 5 blastocyst transfer (7)(8)(9). Conversely, there is a paucity of evidence evaluating the shorter duration of progesterone exposure. Given the relative importance of the outcomes associated with differing durations of progesterone exposure, it is of critical importance that this factor should be taken into consideration (10,11). ...
Objective:
Timing of frozen embryo transfer (FET) within a purported window of implantation is of increasing interest, and there is a paucity of evidence surrounding the transfer of frozen embryos early within these frozen embryo transfer protocols. This study aimed to evaluate whether live birth rates were equivalent after FET of blastocysts 4 days after luteinizing hormone (LH) surge in a true natural cycle protocol, compared to a hormone replacement (HR) protocol.
Materials and methods:
Single-centre, retrospective cohort study involving patients undergoing autologous frozen blastocyst transfer from January 1st, 2013, to December 31st, 2016. Cycles were grouped according to their protocol: true natural cycle (hormonal detection of LH surge with FET scheduled four days later) versus HR cycle (luteal phase gonadotropin-releasing hormone agonist suppression, oral or vaginal estradiol and intramuscular progesterone starting five days before FET). A total of 850 cycles were included, 501 true natural cycles and 349 HR cycles. The primary outcome was the live birth rate, secondary outcomes included clinical pregnancy rate and miscarriage. Logbinomial regression models were performed adjusting for a priori selected variables.
Results:
Adjusted resulted in live birth rates of 38.7 and 40.4%, [adjusted risk ratio (aRR): 0.96, 95% confidence interval (CI): 0.76-1.22, P=0.729] in the natural cycle and HR groups, respectively. The secondary outcome analyses did not demonstrate any statistically significant difference in the rate of positive human chorionic gonadotropin (hCG), clinical intrauterine pregnancy rate, or miscarriage rate.
Conclusion:
The timing of the FET four days after LH surge in a true natural cycle protocol results in equivalent live birth rates compared to a HR protocol. Results of this study suggest that the window of implantation within the natural cycle may be less finite than currently believed and further prospective studies evaluating the timing of frozen embryo transfer are warranted.
... For fertilization to take place, the embryo at the appropriate stage of development must appear in the uterine cavity at a strictly defined, individually differentiated time called window of implantation (WOI), in which numerous hormonally controlled cellular, molecular and biochemical processes determine the proper development of the endometrium [4,5]. In natural cycle, this period occurs in mid-secretory phase, between days 6-10 after ovulation and is limited to approximately 48 hours [6]. The cause of endometrial receptivity disorders is believed to be disturbed expression of cytokines and endometrial surface proteins. ...
The continuous development of assisted reproductive techniques (ART) implies the search for solutions that could increase the effectiveness ofavailable methods. In the context of in vitro fertilization (IVF), a significant proportion of failures are due to unsuccessful embryo transfers. At this stage the most important issue is proper dialogue between implanting embryo and the maternal endometrium. Therefore, it seems justified to assess endometrial receptivity (ER), defined as the tissue's ability to accept an embryo to attach and invade into the mucosa. Window of implantation (WOI), is a certain period in which implantation of the properly developed embryo is possible. The cause of endometrial receptivity disorders is believed to be the disturbed expression of cytokines and endometrial surface proteins, the presence of which has been proven in commonly diagnosed diseases such as endometriosis or chronic endometritis. Despite many years of research on endometrial receptivity, the area of diagnostic methods enabling clinical monitoring of ER still remains undeveloped. The aim of this study is to review the utility of selected markers and the available methods of ER assessment, ranging from noninvasive ultrasound, through endometrial fluid analysis, to genomic studies based on endometrial biopsy, in order to increase the effectiveness of IVF. Such an approach could potentially be a significant step towards personalizing medical procedures especially in patients diagnosed with repeated implantation failure (RIF).
... Despite tremendous advances in the field of assisted reproduction technologies (ART), the success rate of embryo transfer remains less than 50%, mostly due to the embryo's inability to implant [2]. Deciphering the causes for this unique situation is a subject of vigorous scientific inquiry, given that the morphological quality of the embryo does not correlate completely with the rate of implantation or successful birth, even in cases where the uterine environment is optimal for implantation [3]. ...
One of the most critical steps in mammalian reproduction is implantation. Embryos with an impaired capacity for embryo–maternal crosstalk are thought to have a reduced potential for implantation. One agent of embryo–maternal communication is extracellular vesicles (EV). EVs are lipid bilayer-bound biological nanoparticles implicated in intercellular communication between many of the known cell types. In the current study, we isolated EVs from trophoblast analogue JAr spheroids and supplemented the EVs with receptive endometrium analogue RL95-2 cells to simulate pre-implantation embryo–maternal dialogue. The transcriptome of the endometrial cells was examined at 30 min, 4 h and 48 h intervals using Oxford Nanopore® technology. At the time points, 30 min, 4 h and 48 h, the endometrial cells showed a significantly altered transcriptome. It seems trophoblast EVs induce a swift and drastic effect on the endometrial transcriptome. The effect peaks at around 4 h of EV supplementation, indicating a generalized effect on cell physiology. Alterations are especially apparent in biological pathways critical to embryonic implantation, such as extracellular matrix–receptor interactions and cytokine–receptor interactions. These observations can be helpful in elucidating the dynamics of embryo–maternal communication in the pre-implantation period.
... Endometrial receptivity(ER) refers to the combined ability of the endometrium to allow embryo positioning, adhesion, invasion implantation, growth, differentiation, metaphase and immune regulation during the window of implantation (WOI) approximately day 20-24 of menstruation, influenced by various regulatory factors [3][4][5][6]. To better understand and describe endometrial receptivity, Noyes et al. [7] first presented histological assays in the 1950s. ...
Objective
To investigate the predictive value of three-dimensional ultrasound assessment of endometrial receptivity in PGD/PGS transplantation patients on pregnancy outcome.
Methods
280 patients undergoing PGD/PGS transplantation were enrolled and divided into group A and group B according to the patients’ pregnancy outcomes. The general conditions, endometrial receptivity indexes of the two groups were compared. Multifactorial logistic regression analysis was used to determine the factors influencing pregnancy outcome in PGD/PGS transplant patients. ROC curves were plotted to analyze the predictive value of 3D ultrasound parameters on pregnancy outcome. The results of the study were validated with patients who underwent FET transplantation, and the patients in the validation group were treated with the same 3D ultrasound examination method and treatment plan as the observation group.
Results
The differences in basic situations between two groups were not statistically significant (P > 0.05). The percentage of endometrial thickness, endometrial blood flow, and endometrial blood flow classification type II + II were higher in group A than in group B (P < 0.05). Multifactorial logistic regression analysis showed that endometrial thickness, endometrial blood flow and endometrial blood flow classification were influencing factors of pregnancy outcome in PGD/PGS patients. The sensitivity of predicting pregnancy outcome based on the results of transcatheter 3D ultrasound was 91.18%, the specificity was 82.35%, and the accuracy was 90.00%, which has a high predictive value.
Conclusion
3D ultrasound can predict pregnancy outcome by assessing the endometrial receptivity of PGD/PGS transplantation, in which endometrial thickness and endometrial blood flow have a good predictive value.
... As the volume of the blastocoel fluid increases, it exerts hydrostatic pressure to break the zona pellucida membrane and eventually lets the blastocyst attach to the endometrial lining near the uterine fundus ( Figure 7A). This process is known as hatching and occurs about 9 days after ovulation (Sathananthan, Menezes, and Gunasheela 2003;Wilcox, Baird, and Weinberg 1999). Since the blastula in placental mammals lacks a yolk, the embryo exchanges gases and other substances with the mother's blood through the placenta, which connects the embryo to the endometrium (Gude et al. 2004). ...
... In a natural cycle, the WOI is open during the mid-luteal phase, which is driven by the sequential actions of estradiol (E 2 ) and progesterone (P). Notably, different definitions of the time of implantation in terms of the time of human chorionic gonadotropin (hCG) appearance in maternal urine have been used, and they include 8 to 10 days after ovulation [1], days 7-9 after the urine luteinizing hormone (LH) surge (LH + 7-9) [2], and day 7 after the urine or serum LH peak (LH + 7) [3,4]. It appears that no consensus has been reached on the definition of WOI. ...
Background:
In an in vitro fertilization (IVF) cycle, the embryo ends its wandering time and begins the process of implantation into the uterine cavity on the seventh day after oocyte pick-up (OPU + 7), which is closer than OPU + 5 to the time of nidation. Therefore, measuring the oestradiol (E2)/progesterone (P) ratio on OPU + 7 may be helpful for predicting pregnancy outcomes.
Methods:
This is a retrospective cohort study of 2,257 women undergoing a follicular-phase depot gonadotropin-releasing hormone agonist (GnRH-a) protocol for in vitro fertilization /intracytoplasmic sperm injection (IVF/ICSI) treatment and fresh blastocyst embryo transfer cycles at a university-affiliated fertility center between January 2016 and April 2021. First, 2,257 women were split into two groups based on clinical pregnancy for analyzing the levels of E2 and P and the E2/P ratio on the day of OPU + 2, OPU + 5 and OPU + 7. And then 2,257 cycles were stratified into three groups based on E2/P ratio tertiles on OPU + 7: the low group (1.3-15.7 pg/ng), middle group (15.7-28.8 pg/ng), and high group (28.8-487.2 pg/ng). The threshold effect of the E2/P ratio on OPU + 7 on live birth was investigated using a two-piecewise linear regression model and a smoothing function curve.
Results:
The level of P in the clinical pregnancy group were lower than that in the nonclinical pregnancy group on both OPU + 2 and OPU + 7 (201.9 ± 71.6 ng/ml vs 213.1 ± 77.6 ng/ml, 89.5 ± 88.5 ng/ml vs 99.5 ± 94.9 ng/ml, P < 0.05). The E2/P ratio in the clinical pregnancy group were higher than that in the nonclinical pregnancy group on both OPU + 2 and OPU + 7 (8.4 ± 6.5 pg/ng vs 8.0 ± 6.8 pg/ng, 32.3 ± 38.5 pg/ng vs 25.2 ± 31.0 pg/ng, P < 0.01). The E2/P ratio on OPU + 7 was positively associated with positive hCG (adjusted OR = 1.01; 95% CI, 1.01-1.02; P < 0.0001), clinical pregnancy (adjusted OR = 1.01; 95% CI, 1.00-1.01; P = 0.0067) and live birth (adjusted OR = 1.01; 95% CI, 1.00-1.01; P < 0.001), and a nonlinear correlation was observed between the E2/P ratio and LBR on OPU + 7.
Conclusions:
A higher E2/P ratio is associated with a higher LBR, but the E2/P ratio should be maintained within a suitable range.
... Endometrial receptivity refers to the combined ability of the endometrium to allow embryo positioning, adhesion, invasion implantation, growth, differentiation, metaphase and immune regulation during the window of implantation(WOI) approximately day 20-24 of menstruation, in uenced by various regulatory factors [3][4][5][6]. To better understand and describe endometrial receptivity, Noyes et al. [7] rst presented histological assays in the 1950. ...
Objective: To investigate the predictive value of three-dimensional ultrasound assessment of endometrial receptivity in PGD/PGS transplantation patients on pregnancy outcome.
Methods: 280 patients undergoing PGD/PGS transplantation were selected and divided into group A and group B according to the patients' pregnancy outcomes. The general conditions, endometrial receptivity indexes of the two groups were compared. Multifactorial logistic regression analysis was used to determine the factors influencing pregnancy outcome in PGD/PGS transplant patients. ROC curves were plotted to analyze the predictive value of 3D ultrasound parameters on pregnancy outcome. The results of the study were validated with patients who underwent FET transplantation, and the patients in the validation group were treated with the same 3D ultrasound examination method and treatment plan as the observation group.
Results: The differences in basic situations between two groups were not statistically significant (P > 0.05). The percentage of endometrial thickness, number of blood flow branches, and blood flow typing type II+II were higher in group A than in group B (P < 0.05). Multifactorial logistic regression analysis showed that endometrial thickness, number of endometrial blood flow branches and endometrial blood flow typing were influencing factors of pregnancy outcome in PGD/PGS patients. The sensitivity of predicting pregnancy outcome based on the results of transcatheter 3D ultrasound was 91.18%, the specificity was 82.35%, and the accuracy was 90.00%, which has a high predictive value.
Conclusion: 3D ultrasound can predict pregnancy outcome by assessing the endometrial receptivity of PGD/PGS transplantation, in which endometrial thickness and endometrial blood flow branch number have a good predictive value.
... Non-conception pooled samples include two specimens from after the end of menses but before ovulation, and one specimen from after ovulation. Conception cycle pooled samples contain two specimens from after the end of menses and before ovulation, and one specimen from after ovulation/conception but before implantation, which typically occurs 8-10 days after ovulation (Wilcox et al., 1999). ...
STUDY QUESTION
Are urinary phenol concentrations of methylparaben, propylparaben, butylparaben, triclosan, benzophenone-3, 2,4-dichlorophenol or 2,5-dichlorophenol associated with fecundability and early pregnancy loss?
SUMMARY ANSWER
2,5-dichlorophenol concentrations were associated with an increased odds of early pregnancy loss, and higher concentrations of butylparaben and triclosan were associated with an increase in fecundability.
WHAT IS KNOWN ALREADY
Phenols are chemicals with endocrine-disrupting potential found in everyday products. Despite plausible mechanisms of phenol reproductive toxicity, there are inconsistent results across few epidemiologic studies examining phenol exposure and reproductive function in non-fertility treatment populations.
STUDY DESIGN, SIZE, DURATION
Specimens and data were from the North Carolina Early Pregnancy Study prospective cohort of 221 women attempting to conceive naturally from 1982 to 1986. This analysis includes data from 221 participants across 706 menstrual cycles, with 135 live births, 15 clinical miscarriages and 48 early pregnancy losses (before 42 days after the last menstrual period).
PARTICIPANTS/MATERIALS, SETTING, METHODS
Participants collected daily first-morning urine specimens. For each menstrual cycle, aliquots from three daily specimens across the cycle were pooled within individuals and analyzed for phenol concentrations. To assess sample repeatability, we calculated intraclass correlation coefficients (ICCs) for each phenol. We evaluated associations between phenol concentrations from pooled samples and time to pregnancy using discrete-time logistic regression and generalized estimating equations (GEE), and early pregnancy loss using multivariable logistic regression and GEE.
MAIN RESULTS AND THE ROLE OF CHANCE
ICCs for within-person variability across menstrual cycles in pooled phenol concentrations ranged from 0.42 to 0.75. There was an increased odds of early pregnancy loss with 2,5-dichlorophenol concentrations although the CIs were wide (5th vs 1st quintile odds ratio (OR): 4.79; 95% CI: 1.06, 21.59). There was an increased per-cycle odds of conception at higher concentrations of butylparaben (OR: 1.62; 95% CI: 1.08, 2.44) and triclosan (OR: 1.49; 95% CI: 0.99, 2.26) compared to non-detectable concentrations. No associations were observed between these endpoints and concentrations of other phenols examined.
LIMITATIONS, REASONS FOR CAUTION
Limitations include the absence of phenol measurements for male partners and a limited sample size, especially for the outcome of early pregnancy loss, which reduced our power to detect associations.
WIDER IMPLICATIONS OF THE FINDINGS
This study is the first to use repeated pooled measures to summarize phenol exposure and the first to investigate associations with fecundability and early pregnancy loss. Within-person phenol concentration variability underscores the importance of collecting repeated samples for future studies. Exposure misclassification could contribute to differences between the findings of this study and those of other studies, all of which used one urine sample to assess phenol exposure. This study also contributes to the limited literature probing potential associations between environmental exposures and early pregnancy loss, which is a challenging outcome to study as it typically occurs before a pregnancy is clinically recognized.
STUDY FUNDING/COMPETING INTEREST(S)
This research was supported by the National Institute of Environmental Health Sciences of the National Institutes of Health (award number F31ES030594), the Intramural Research Program of the National Institutes of Health, the National Institute of Environmental Health Sciences (project numbers ES103333 and ES103086) and a doctoral fellowship at the Yale School of Public Health. The authors declare they have no competing interests to disclose.
TRIAL REGISTRATION NUMBER
N/A.
... In endometriosis, mRNAs for ErbB-1 and ErbB-3 are upregulated in eutopic endometrium of women with endometriosis [20][21][22]. To our knowledge, there is a lack of knowledge regarding the association between endometriosis and the expression of ErbB receptor family proteins in human endometrium during the window of implantation (WOI), i.e., days 20-24 of a typical 28-day menstrual cycle [23,24]. The accrued information, as summarized in Table 1, generally fails to provide any useful understanding in this regard, because the reported studies mostly failed to adhere to the WERF EPHect guidelines [25,26] and did not address the specific issue of cellular expression of ErbB family proteins in implantation-stage endometrium [19][20][21][22]. ...
The strong association between endometriosis and infertility is of high clinical significance. High proliferative bias in eutopic endometrium during the secretory phase is a hallmark of endometriosis, which may result in high occurrence of implantation failure and resultant infertility in endometriosis. The ErbB family of proteins regulates the proliferation capacity in the endometrium, potentially causing endometrial hostility to the implantation process in endometriosis. However, our knowledge regarding the involvement of the ErbB family in human endometrium during the window of implantation (WOI) in endometriosis-associated infertility is scant. In the present study, the cellular profiles of immunopositive ErbBs-1 to -4 in the endometrium of endometriosis-free, infertile women (Group 1; n = 11) and in eutopic endometrium of infertile women diagnosed with stage IV ovarian endometriosis (Group 2; n = 13) during the mid-secretory phase were compared using standardized guidelines. Computer-aided standardized combinative analysis of immunoprecipitation in different compartments revealed an overexpression of ErbB-1 in the epithelial, stromal and vascular compartments, along with marginally higher ErbB-3 expression (p < 0.06) in the vascular compartment and ErbB-4 expression (p < 0.05) in the glandular epithelium and stroma in the endometrium during the WOI in women with primary infertility associated with stage IV ovarian endometriosis compared with disease-free endometrium of control infertile women. It appears that changes in ErbBs in the eutopic endometrium during WOI induce anomalous proliferative, inflammatory and angiogenic activities in it, which can antagonize endometrial preparation for embryo implantation in endometriosis. This knowledge appears usable in strategizing methods for the treatment of endometriosis-associated infertility, as well as preempting the oncogenic potential of endometriosis.
Background and objectives:
The 9-valent human papillomavirus (9vHPV) vaccine Phase III immunogenicity study in 9- to 15-year-old boys and girls was extended to assess immunogenicity and effectiveness through 10 years after the last vaccine dose (NCT00943722).
Methods:
Boys (n = 301) and girls (n = 971) who received three 9vHPV vaccine doses in the base study (day 1, months 2 and 6) enrolled in the extension. Serum was collected through month 126 for antibody assessments by competitive Luminex immunoassay and immunoglobulin G-Luminex immunoassay. For effectiveness analysis starting at age 16 years, genital swabs were collected (to assess HPV DNA by polymerase chain reaction) and external genital examinations conducted every 6 months. Primary analyses were conducted in per-protocol populations.
Results:
Geometric mean antibody titers peaked around month 7, decreased sharply between months 7 and 12, then gradually through month 126. Seropositivity rates remained ≥81% by competitive Luminex immunoassay and ≥95% by immunoglobin G-Luminex immunoassay at month 126 for each 9vHPV vaccine type. After up to 11.0 (median 10.0) years of follow-up postdose 3, there were no cases of HPV6/11/16/18/31/33/45/52/58-related high-grade intraepithelial neoplasia or condyloma in males or females. Incidence rates of HPV6/11/16/18/31/33/45/52/58-related 6-month persistent infection in males and females were low (54.6 and 52.4 per 10000 person-years, respectively) and within ranges expected in vaccinated cohorts, based on previous human papillomavirus vaccine efficacy trials.
Conclusions:
The 9vHPV vaccine demonstrated sustained immunogenicity and effectiveness through ∼10 years post 3 doses of 9vHPV vaccination of boys and girls aged 9 to 15 years.
Gestational trophoblastic disease (GTD) represents a spectrum of lesions characterised by an abnormal proliferation of trophoblast, including complete hydatidiform mole, partial hydatidiform mole, invasive hydatidiform mole, choriocarcinoma, placental site trophoblastic tumour, epithelioid trophoblastic tumour, placental site nodule and plaque, and exaggerated placental site reaction.[1] Complete mole is characterised by gross hydropic villous swelling with some degree of circumferential and haphazard trophoblast proliferation microscopically.[2] The incidence of pregnancy in perimenopausal women is extremely low. Most pregnancies that occur will end in spontaneous abortion. In the remaining pregnancies the incidence of GTD is greatly increased.[3] Benign gestational trophoblastic diseases generally occur in younger women of reproductive age and is extremely rare in peri and post menopausal women. Only isolated cases of hydatidiform mole in elderly women have been reported in the literature[3,4]. We report on a patient aged 47 years with a complete hydatidiform mole to emphasise that this diagnosis should still be considered at an older age.
This study evaluated β-hCG changes during the early period of pregnancy in an attempt to predict successful pregnancy outcomes in ART. It determined the median values of the β-hCG and the 2-day β-hCG increments of clinical vs. biochemical pregnancies. The results of fresh day 3 embryo, frozen day 3 embryo and frozen day 5 embryo transfers were evaluated. The cutoff values of β-hCG and the 2-day increments predicting clinical pregnancy and delivery were determined. All women who underwent embryo transfer and had a singleton pregnancy from January 2017-December 2019 were included. As expected, clinical pregnancies had higher initial median β-hCG values compared to biochemical pregnancies (fresh day 3 (400 vs. 73 mIU/ml), frozen day 3 (600 vs. 268.5 mIU/ml) and frozen day 5 (937 vs. 317 mIU/ml). Nonetheless, the abortion rate was significantly lower in the group with β-hCG above the cutoff values in fresh (141 mIU/ml), and frozen (354.5 mIU/ml) cleavage stage transfers (17.2% vs. 44%, P<0.001 and 18.5% vs. 38%, P=0.003, respectively). Blastocyst transfers resulted in higher median initial β-hCG compared to cleavage embryo transfers (937 vs. 600 mIU/ml), and the initial β-hCG values from frozen cleavage embryos were higher compared to fresh cleavage embryos (600 vs. 400 mIU/ml). Earlier implantation in frozen cycles may be caused by freezing-thawing procedures. Moreover, in fresh cycles, negative effects of the hormonal milieu of fresh cycles may delay implantation. Results indicate that high initial β-hCG and high 2-day β-hCG increments demonstrated better outcomes, including more clinical pregnancies and fewer abortions.
An outbreak of births of microcephalic patients in Brazil motivated multiple studies on this incident. The data left no doubt that infection by Zika virus (ZIKV) was the cause, and that this virus promotes reduction in neuron numbers and neuronal death. Analysis of patients' characteristics revealed additional aspects of the pathology alongside the decrease in neuronal number. Here, we review the data from human, molecular, cell and animal model studies attempting to build the natural history of ZIKV in the embryonic central nervous system (CNS). We discuss how identifying the timing of infection and the pathways through which ZIKV may infect and spread through the CNS can help explain the diversity of phenotypes found in congenital ZIKV syndrome (CZVS). We suggest that intraneuronal viral transport is the primary mechanism of ZIKV spread in the embryonic brain and is responsible for most cases of CZVS. According to this hypothesis, the viral transport through the blood-brain barrier and cerebrospinal fluid is responsible for more severe pathologies in which ZIKV-induced malformations occur along the entire anteroposterior CNS axis.
The precise control of endometrial receptivity is crucial for successful embryo implantation, which is strictly regulated by the ovarian steroid hormones estrogen and progesterone. Despite our improved understanding of the genetic regulation of implantation downstream of the action of hormones, we do not know much about the epigenetic regulation that occurs during early pregnancy. To investigate the role of the N6-methyladenosine (m6A) RNA modification in embryo implantation, we generated mice with conditional deletion of Mettl14, a core component of the m6A writer complex, in the uterus. These mice were infertile due to implantation failure. We showed that Mettl14-deficient uteri had aberrant upregulation of estrogen receptor α (ERα) signaling and ERα phosphorylation, but progesterone receptor (PGR) signaling was largely unaffected. Additionally, Mettl14 deletion led to abnormal activation of the innate immune pathway in Mettl14-deficient uteri. This effect was accompanied by the infiltration of immune cells, such as macrophages and dendritic cells, into the basal region of the endometrial epithelium. Methylated RNA immunoprecipitation sequencing (MeRIP-seq) showed that genes involved in the innate immune response had decreased m6A peaks in Mettl14-deficient mice. These results suggest that Mettl14 plays a crucial role in successful implantation by precisely regulating both ERα signaling and innate immunity in the uterus.
Endometriosis is a prevalent gynecological condition associated with pelvic pain and infertility. Despite more than a century of research, the etiology of endometriosis still eludes scientific consensus. This lack of clarity has resulted in suboptimal prevention, diagnosis, and treatment options. Evidence of genetic contributors to endometriosis is interesting but limited; however, significant progress has been made in recent years in identifying epigenetic role in the pathogenesis of endometriosis through clinical studies, in vitro cell culture experiments, and in vivo animal models. The predominant findings include endometriosis-related differential expression of DNA methyltransferases and demethylases, histone deacetylases, methyltransferases, and demethylases, and regulators of chromatin architecture. There is also an emerging role for miRNAs in the control of epigenetic regulators in the endometrium and endometriosis. Changes in these epigenetic regulators result in differential chromatin organization and DNA methylation with consequences for gene expression independent of a genetic sequence. Epigenetically altered expression of genes related to steroid hormone production and signaling, immune regulation, and endometrial cell identity and function have all been identified and appear to play into the pathophysiological mechanisms of endometriosis as well as resulting infertility. This review summarizes and critically discusses early seminal findings, the ever-growing recent evidence of epigenetic contributions to the pathophysiology of endometriosis, and implications for proposed epigenetically targeted therapeutics.
Objective: To explore the effect of low dose prednisone treatment during pregnancy on blood glucose levels in patients with spontaneous abortion.
Methods: In this single-center, prospective cohort study, patients with a history of spontaneous abortion were enrolled and were assigned to two groups according to whether they were exposed to low dose prednisone during pregnancy. All patients received oral glucose tolerance test (OGTT) at early pregnancy (before 12th week) and late pregnancy (24-28th week). Fasting serum C-peptide and plasma glycosylated hemoglobin (HbA1c) levels were measured at the same time. We compared the results of OGTT, fasting serum C-peptide levels and HbA1c levels between the two groups and analyzed the incidence of diabetes mellitus (DM), impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in early pregnancy and the incidence of gestational diabetes mellitus (GDM) in late pregnancy.
Result: A total of 355 patients were enrolled and analyzed. No significant difference in OGTT between the two groups were observed in the first trimester (P=0.142). However, patients in the prednisone group showed a significant increase in fasting serum C-peptide (P<0.001). Regarding late pregnancy, although there was no significant difference in OGTT between the two groups (P=0.070), patients in the prednisone group showed a significant increase in 2-h plasma glucose (P=0.010). Patients in the prednisone group also had a higher incidence of GDM compared with the control group (P=0.005). Furthermore, family history of DM and receiving low dose prednisone were significantly associated with higher risk of gestational glycometabolism abnormality and receiving HCQ reduced the risk of that in patients with spontaneous abortion.
Conclusion: Long-term exposure of low dose prednisone during pregnancy could impair postprandial blood glucose and increase the incidence of GDM. Routine monitor of blood glucose and C-peptide levels should be recommended in patients who received prednisone treatment during pregnancy. Family history of DM and exposure to low dose prednisone are both independent risk factors for gestational glycometabolism abnormality while receiving HCQ is a protective one in patients with spontaneous abortion.
Trial registration
Chinese Clinical Trials Registration: ChiCTR2100046455 (16/05/2021).
The remarkable potential of human endometrium to undergo spontaneous remodeling is shaped by controlled spatiotemporal gene expression patterns. Although hormone-driven transcription shown to govern these patterns, the post-transcriptional processing of these mRNA transcripts, including the mRNA splicing in the endometrium is not studied yet. Here, we report that the splicing factor, SF3B1 is central in driving alternative splicing (AS) events that are vital for physiological responses of the endometrium. We show that loss of SF3B1 splicing activity impairs stromal cell decidualization as well as embryo implantation. Transcriptomic analysis revealed that SF3B1 depletion decidualizing stromal cells led to differential mRNA splicing. Specifically, a significant upregulation in mutually exclusive AS events (MXEs) with SF3B1 loss resulted in the generation of aberrant transcripts. Further, we found that some of these candidate genes phenocopy SF3B1 function in decidualization. Importantly, we identify progesterone as a potential upstream regulator of SF3B1-mediated functions in endometrium possibly via maintaining its persistently high levels, in coordination with deubiquitinating enzymes. Collectively, our data suggest that SF3B1-driven alternative splicing plays a critical role in mediating the endometrial-specific transcriptional paradigms. Thus, the identification of novel mRNA variants associated with successful pregnancy establishment may help to develop new strategies to diagnose or prevent early pregnancy loss.
Selecting the best embryo to transfer to the uterus is key to successful in vitro fertilization (IVF). A huge amount of research has been devoted to this topic and there are numerous methods used, from simple morphological assessment to molecular biological techniques to assess the genome and metabolism of the newly fertilized embryo. For many of these techniques, an adequate evidence base is lacking, and expert opinion is valuable. Clinical imperatives require ranking all embryos in a cohort according to their viability, thereby enabling the selection of the best embryo to optimize live birth outcome: a key indicator used to measure and rate IVF Clinics worldwide. This clear and informative manual will provide embryologists and clinicians with an overview of the tools now available to assist in embryo selection, as well as evidence for their efficacy and safety and the broader considerations that must underlie these important clinical decisions.
Increasing progesterone (P4) during early conceptus development may be crucial for establishment of pregnancy in dairy cattle. The objective of this study was to determine if human chorionic gonadotropin (hCG) at various times after ovulation will increase serum P4 during elongation and increase the chances for, and reduce variability to, initial increase in pregnancy-specific protein B (PSPB) following artificial insemination (AI). Time to PSPB increase was defined as the first day of increase in concentrations of PSPB between d 18 and 28 after ovulation in cows with ≥12.5% increases for 3 consecutive days compared with baseline. Lactating cows (n = 368) synchronized to Double-Ovsynch (first service) or Ovsynch (second or greater service) received one of 4 treatments: no hCG (control), or 3,000 IU of hCG on d 2 (D2), 2 and 5 (D2+5), or 5 (D5) after ovulation. All cows were examined via ultrasound on d 5 and 10 postovulation to determine percentage of cows with hCG-induced accessory CL (aCL) and to quantify and measure all luteal structures. Samples for serum P4 were collected on d 0, 5, 19, and 20 postovulation. The P4 was increased in D2, D2+5, and D5 groups compared with control. The D2+5 and D5 treatments increased aCL and P4 compared with D2 and control. The D2 treatment increased P4 on d 5 after ovulation compared with control. Serum PSPB samples were collected daily from all cows on d 18 through 28 after ovulation for determination of d of PSPB increase. Pregnancy diagnoses were performed via ultrasound examination on d 35, 63, and 100 after ovulation and AI. The D5 treatment reduced percentage of cows with, and increased the time to, PSPB increase. Primiparous cows with ipsilateral aCL had reduced pregnancy loss before d 100 postovulation compared with cows with contralateral aCL. Cows that had PSPB increase >21 d postovulation had 4× greater chances of pregnancy loss compared with cows that had PSPB increase on d 20 or 21. The highest quartile of P4 on d 5, but not on d 19 and 20, was associated with reduced time to PSPB increase. Time to PSPB increase appears to be an important measurement to understand reasons for pregnancy loss in lactating dairy cows. Increasing P4 utilizing hCG after ovulation did not enhance early pregnancy or reduce pregnancy losses in lactating dairy cows.
Purpose of review:
Assisted reproductive technology treatment has seen a significant shift from fresh to frozen embryo transfers (FET). Endometrial receptivity in the FET cycle can be achieved through a hormonal replacement cycle or a natural cycle, and the preparation approach has important implications on the pregnancy itself. In the natural cycle approach, planning of the embryo transfer timing might be challenging due to the need to identify ovulation correctly.
Recent findings:
Ovulation in a natural cycle is characterized by a luteinizing hormone surge, followed by the rise in progesterone (P4) levels, inducing secretory transformation. However, the luteinizing hormone surge can vary widely in its pattern, amplitude and duration and might not even result in the formation of a corpus luteum and P4 production. Monitoring of the luteinizing hormone surge using urinary luteinizing hormone kits might be a convenient approach, however, it is deemed unreliable and should be considered inadequate for securing the best outcome of a FET cycle.
Summary:
Endometrial receptivity depends on the duration of progesterone exposure to the adequately estrogenized endometrium. In a natural cycle endometrial preparation approach, correct planning for the embryo transfer timing should include the measurement of luteinizing hormone, estradiol and P4.
Human early development sets the stage for embryonic and adult life but remains difficult to investigate. A solution came from the ability of stem cells to organize into structures resembling preimplantation embryos—blastocysts—that we termed blastoids. This embryo model is available in unlimited numbers and could thus support scientific and medical advances. However, its predictive power depends on how faithfully it recapitulates the blastocyst. Here, we describe how we formed human blastoids that (1) efficiently achieve the morphology of the blastocyst and (2) form lineages according to the pace and sequence of blastocyst development, (3) ultimately forming cells that transcriptionally reflect the blastocyst (preimplantation stage). We employ three different commercially available 96- and 24-well microwell plates with results similar to our custom-made ones, and show that blastoids form in clinical in vitro fertilization medium and can be cryopreserved for shipping. Finally, we explain how blastoids replicate the directional process of implantation into endometrial organoids, specifically when these are hormonally stimulated. It takes 4 d for human blastoids to form and 10 d to prepare the endometrial implantation assay, and we have cultured blastoids up to 6 d (time-equivalent of day 13). On the basis of our experience, we anticipate that a person with ~1 year of human pluripotent stem cell culture experience and of organoid culture should be able to perform the protocol. Altogether, blastoids offer an opportunity to establish scientific and biomedical discovery programs for early pregnancy, and an ethical alternative to the use of embryos. The authors present a protocol for the generation of human blastoids—structures morphologically and transcriptionally resembling complete blastocysts—from pluripotent stem cells and for their use in modeling implantation into hormonally stimulated endometrial cells.
Implantation success relies on intricate interplay between the developing embryo and the maternal endometrium. Extracellular vesicles (EVs) represent an important player of this intercellular signalling through delivery of functional cargo (proteins and RNAs) that reprogram the target cells protein and RNA landscape. Functionally, the signalling reciprocity of endometrial and embryo EVs regulates the site of implantation, preimplantation embryo development and hatching, antioxidative activity, embryo attachment, trophoblast invasion, arterial remodelling, and immune tolerance. Omics technologies including mass spectrometry have been instrumental in dissecting EV cargo that regulate these processes as well as molecular changes in embryo and endometrium to facilitate implantation. This has also led to discovery of potential cargo in EVs in human uterine fluid and embryo spent media of diagnostic and therapeutic value in implantation success, fertility, and pregnancy outcome. This review discusses the contribution of EVs in functional hallmarks of embryo implantation, and how the integration of various omics technologies is enabling design of EV‐based diagnostic and therapeutic platforms in reproductive medicine. This article is protected by copyright. All rights reserved
Abstract Men in couples that have experienced pregnancy loss have a higher risk of sexual dysfunction. Semen quality impairment is common in men of couples with pregnancy loss. The objective of this article is to evaluate the differences in the incidence of male sexual dysfunction in a cohort of pregnancy loss couples with different types of semen quality impairment. A cross-sectional analysis of 426 men who attended our outpatient clinic for couples’ pregnancy loss, those without genetic abnormalities were included in the final analysis covering June 2021 to October 2021. The patients were divided into 5 groups according to type of semen quality impairment: normozoospermia group (group normal; N = 161), high sperm DNA fragmentation group (group high-SDF; N = 87), isolated asthenozoospermia group (group iAstheno; N = 45), isolated teratozoopermia group (group iTerato; N = 44), and ≥ 2 abnormal sperm parameters group (group multiple; N = 89). All subjects underwent a complete physical inspection, including palpation of the male genitalia and semen analysis. Validated assessment tools for erectile dysfunction (the International Index of Erectile Function -IIEF-5) and anxiety (the seven-item Generalized Anxiety Disorder Scale- GAD-7) were also used. Men with high sperm DNA fragmentation and isolated teratozoopermia were associated with increased erectile dysfunction risk when compared with normozoospermic men, with an OR of 2.75 [1.49–5.09; p = 0.001] and 2.44 [1.22–5.31; p = 0.024], respectively. It is interesting to note that there was no difference in prevalence of erectile dysfunction between Group iAstheno and Group normal (20.0% vs. 18.0%; OR = 1.24 [0.52–2.97]; P = 0.625). More than half (50.6%) of the participants in Group high-SDF reported sexual intercourse less than once per week, much more than those in the normozoospermia group (23.2%, p
Purpose
: Implantation is a limiting factor for treatment success in assisted reproduction. Both embryonic and endometrial factors contribute to implantation. Embryonic factors have often been ignored in previous studies about the role of endometrium in implantation. In this study, we sought to identify the endometrial genes associated with negative pregnancy outcomes following the transfer of a single euploid blastocyst.
Methods
: Computational analyses of the transcriptomes of mid-secretory endometria from nine pregnant and seven non-pregnant patients in a cycle preceding the transfer of a single euploid blastocyst in a vitrified-warmed cycle were performed.
Results
: Principal component analysis of two reported endometrial receptivity gene sets showed close clustering of the pregnant and non-pregnant samples. Differential gene expression analysis and co-expression module analysis identified 131 genes associated with the pregnancy status. The endometrial signatures identified highlight the importance of immune and metabolic regulation in pregnancy outcome. Network analysis identified 20 hub genes that could predict pregnancy outcomes with 88.9% sensitivity and 85.7% specificity. Single-cell gene expression analysis highlighted the regulation of endometrial natural killer cells, T cells, and macrophages during embryo implantation. Immune cell abundance analysis supported the dysregulation of cytotoxic immune cells in the endometria of non-pregnant women.
Conclusions
: We reported the first endometrial gene signature associated with pregnancy after elimination of embryo aneuploidy and highlighted the importance of the endometrial immune microenvironment and metabolic status in pregnancy outcomes.
This article is protected by copyright. All rights reserved
Embryo implantation is a key step in human reproduction, and the endometrium plays a key role in this process. Changes in the receptive state of the endometrium are one of the main reasons for embryo implantation failure. However, the mechanism underlying the altered endometrial receptivity remains unclear. In this study, we recruited 140 women undergoing assisted reproductive technology and divided them into a shifting group and a normal group based on their embryo implantation window results. Endometrial transcriptome data suggested that changes in the remodeling process of decidual spiral arterioles and changes in the immune environment might be important mechanisms of implantation window shift. The functional enrichment analysis results also suggested that the changes in microbiota had an important role in the changes in endometrial status. The endometrial functionally active microbial profiles were obtained based on previously validated metatranscriptomic analysis pipelines. Combining host gene expression information, immune cell abundance information and functionally active microbial abundance and activity information, we found that Treponema succinifaciens, Fusobacterium sp. oral taxon 203 and other potentially harmful species may over-activate Eicosapentaenoic acid (EPA) biosynthesis Thus, the balance of the immune environment of the endometrium is disrupted, resulting in the shift of the implantation window and the failure of embryo implantation.
Importance
Endometrial receptivity testing is purported to improve live birth following frozen embryo transfer by identifying the optimal embryo transfer time for an individual patient; however, data are conflicting.
Objective
To compare live birth from single euploid frozen embryo transfer according to endometrial receptivity testing vs standardized timing.
Design, Setting, and Participants
Double-blind, randomized clinical trial at 30 sites within a multicenter private fertility practice in the Eastern US. Enrollment was from May 2018 to September 2020; follow-up concluded in August 2021. Participants underwent in vitro fertilization, preimplantation genetic testing for aneuploidy, endometrial receptivity testing, and frozen embryo transfer. Those with euploid blastocyst(s) and an informative receptivity result were randomized. Exclusion criteria included recurrent pregnancy loss, recurrent implantation failure, surgically aspirated sperm, donor egg(s), and unmitigated anatomic uterine cavity defects.
Interventions
The intervention group (n = 381) underwent receptivity-timed frozen embryo transfer, with adjusted duration of progesterone exposure prior to transfer, if indicated by receptivity testing. The control group (n = 386) underwent transfer at standard timing, regardless of receptivity test results.
Main Outcomes and Measures
The primary outcome was live birth. There were 3 secondary outcomes, including biochemical pregnancy and clinical pregnancy.
Results
Among 767 participants who were randomized (mean age, 35 years), 755 (98%) completed the trial. All randomized participants were analyzed. The primary outcome of live birth occurred in 58.5% of transfers (223 of 381) in the intervention group vs 61.9% of transfers (239 of 386) in the control group (difference, −3.4% [95% CI, −10.3% to 3.5%]; rate ratio [RR], 0.95 [95% CI, 0.79 to 1.13]; P = .38). There were no significant differences in the intervention vs the control group for the prespecified secondary outcomes, including biochemical pregnancy rate (77.2% vs 79.5%, respectively; difference, −2.3% [95% CI, −8.2% to 3.5%]; RR, 0.97 [95% CI, 0.83 to 1.14]; P = .48) and clinical pregnancy rate (68.8% vs 72.8%, respectively; difference, −4.0% [95% CI, −10.4% to 2.4%]; RR, 0.94 [95% CI, 0.80 to 1.12]; P = .25). There were no reported adverse events.
Conclusions and Relevance
Among patients for whom in vitro fertilization yielded a euploid blastocyst, the use of receptivity testing to guide the timing of frozen embryo transfer, compared with standard timing for transfer, did not significantly improve the rate of live birth. The findings do not support routine use of receptivity testing to guide the timing of embryo transfer during in vitro fertilization.
Trial Registration
ClinicalTrials.gov Identifier: NCT03558399
In generally we can say that the loss of pregnancy during the first 20 to 23 week is called miscarriage. The objective of this study was to determine the effects of miscarriage, reproductive tract and parity and gravidity on women's sexual life and also to know the effects of miscarriage on fertility rate. The study was cross-sectional study, which was done by within six month at the Natun Vuqta Malithia of the Sailkupa Upazila under Jhenaidah District who were affected by miscarriage. The total number of 100 women with the history of miscarriage was included in this study. Data was collected from field through direct interview and the method of data collection was case study method by using a well-developed semi-structured questionnaire. The data analysis was perform through by using software's Microsoft Excel. Among the 100 respondents 74% respondents first delivery were happened between the age 13-20 years and 33% respondents faced the problem during intercourse and among them 41% suffered from abdomen pain, 91% respondents faced problems after miscarriage, 31% respondents faced problem at first conception and 48% respondents have alive children more than one conception. 26% respondents lost their every pregnancy for occurring miscarriage and 81% faced problem to continue pregnancy after miscarriage, 66% could not identify the causes of miscarriage, 72% faced long time physical problem after her miscarriage and the higher 18% were suffering from uterine problems, 48% were suffering from complication like infection after miscarriage. 80% respondents faced heavy bleeding, 67% were suffering from dysmenorrheal. 31% respondents faced problem to attend in social program without having children due to miscarriage which affects on respondents psychological condition.
This study aims to understand differences/similarities in the genetic profile of the endometrium at the start of window of implantation (WOI) in women with unexplained infertility (UI) and unexplained recurrent pregnancy loss (uRPL). Differentially expressed genes (DEGs) from the endometrium were evaluated using gene expression array and pathway enrichment analysis was performed to analyse gene expression pathways involved in both conditions. We found 2,171 genes arranged in 117 pathways and 730 genes arranged in 33 pathways differentially expressed in endometrium of patients in UI and uRPL, respectively. Complement-coagulation cascades, morphine addiction pathway, and PI3K-Akt signalling pathway were predominantly differentially expressed in UI. Cancer pathways, NF-κB signalling pathway, and actin cytoskeleton regulation pathway showed significant changes in uRPL. Forty-eight percent of DEGs and 84% of differentially expressed pathways in uRPL were found in the endometrium of UI patients. Unexpected close association in gene expression pathways between UI and uRPL is observed supporting the hypothesis ‘uRPL is a clinical subset of UI’. Yet 100% DEGs overlap wasn’t found suggesting the endometrium has still some different gene expression patterns at start of WOI in UI and uRPL. Lastly, diagnostic tools may be developed for uRPL because more specific genes-pathways are involved compared with UI, which shows broader genetic expression profile.
Originally published in 2006, this book provides an in-depth account of trophoblast: the tissue derived from the fertilised egg that nourishes and protects the developing fetus. The cells of the trophoblast have many unique qualities, and exhibit great variability across different species. It has a fascinating role in the development of the placenta and as a regulator during early growth of the embryo. These aspects are all fully covered as well as studies on why it is not rejected by the mother as 'foreign' tissue. Disorders of trophoblast during development also manifest themselves in several clinical conditions during pregnancy, including gestational trophoblastic disease and pre-eclampsia. From stem cells through to epigenetics, implantation and X-chromosome inactivation, there is a lot to be learned about trophoblast, this volume provides a detailed summary of knowledge regarding the subject.
Updated in light of recent research findings on fertilization, implantation and early pregnancy, this new edition combines the expertise of a wide range of internationally renowned authors to produce an authoritative, multidisciplinary approach to the management of first-trimester complications. Several international guidelines and consensus statements have been released since publication of the first edition and this has stimulated new focussed research questions that are addressed. The book's key recommendations provide clinicians with the tools to improve the patient's experience of the management of first-trimester complications. By combining essential elements of scientific research and clinical care, Early Pregnancy continues to set a benchmark for evidence-based management and will be essential reading for obstetricians, gynaecologists, neonatologists, ultrasonographers, and nurses seeking an understanding of the reproductive science of early pregnancy.
Genes for chorionic gonadotrophin (CG) are transcribed by the 16-cell embryo stage in humans, but there is no clear evidence of CG secretion as a bioactive dimer before attachment and trophoblast outgrowth stages of implantation. The studies summarized question the timing of CG expression and secretion, the possible roles of CG for intraembryonic differentiation and at the implantation site, and the recognition of this primate embryo-derived signal in support of the corpus luteum. The data suggest that the implantation window in primates may be broader than in non-primate species, where a closer synchrony between embryonic, tubal and uterine events appears to be necessary for embryonic survival. Some preliminary data concerning an association between peripheral thrombocytopenia, ovarian inhibin secretion and peri-implantation stages of embryo development indicate that an unknown embryonic signal may be secreted before bioactive CG can be detected.
Of 48 spare human pre-embryos achieving the expanded blastocyst stage, 22 (45.6%) secreted significant amounts of human chorionic gonadotrophin (HCG) (>5 IU/l/day). Of these, nine remained intrazonal, seven partially hatched and six fully hatched. Embryonic production of HCG in vitro appeared to be time-dependent, starting after a certain minimum time (∼160 h post-insemination) and rising exponentially, with maximal HCG production around day 10. Hatching was not a prerequisite for HCG secretion, since similar amounts were produced by intrazonal blastocysts. Blastocysts derived from abnormally fertilized oocytes also began secreting HCG exponentially but secretion was delayed and the upper limit of maximum HCG secretion rate was comparatively low. The actual amount of HCG is thought to reflect the number of viable trophectoderm cells producing the hormone. HCG doubling times for blastocysts in vitro were rapid when compared to implanting blastocysts of a similar age in vivo, with 19/22 (86.4%) blastocysts having a doubling time of < 10 h. Provided a pre-embryo can secrete HCG and maintain an adequate doubling time, sufficient HCG should be produced for initial stages of embryonic recognition in vivo. Since intrazonal blastocysts are capable of fulfilling both of these criteria, the limiting factor in realizing their full potential may be escaping from the zona pellucida.
Pregnancy rates vary considerably with the type of ovarian stimulation used for in vitro fertilization and embryo transfer (IVF-ET). The window of implantation may represent one of the rate-limiting steps in IVF success. We therefore investigated estimated implantation times of 10 consecutive IVF singleton pregnancies, achieved using pituitary suppression with gonadotropin-releasing hormone agonist (GnRH-a) before and during ovarian stimulation with human menopausal gonadotropins (hMG), and compared those with 9 consecutive IVF pregnancies achieved by hMG stimulation only. Estimated implantation times were calculated by regression analysis of serial human chorionic gonadotropin (hCG) measurements between days 7 and 16 after ET. The GnRH-a/hMG pregnancies implanted between days 7 and 11, whereas hMG pregnancies implanted between days 7 and 9 after ET. The hCG regression curve for the GnRH-a/hMG pregnancies revealed a delay of 1.5 days in estimated implantation time compared with the hMG only group. There were no significant differences in pretransfer in vitro embryos development between the two groups. Thus, the delay in hCG rise probably reflects a delay in embryo implantation. We therefore conclude that a GnRH-a/hMG stimulation protocol appears to widen the implantation window in comparison with a hMG only protocol. This observation may at least in part explain the improved IVF pregnancy success with GnRH-a/hMG stimulation protocols.
We intensively studied 30 women attempting pregnancy in order to lay groundwork for larger studies of early pregnancy loss. These women collected first morning urine specimens for up to 6 months after discontinuing use of birth control. Urine specimens were successfully collected for 98% of the woman-days in the study. Three assays for human chorionic gonadotropin (hCG) were performed on each urine specimen. An immunoradiometric assay (IRMA) specific to the carboxy terminal peptide of the hCG β -chain proved to be more sensitive and more specific than two radioimmunoassays (RIAs). Using the IRMA, we found four cases in which hCG rose and fell over successive days, consistent with early pregnancy loss. For three of these four cases, the level of hCG was too low to be detectable with the RIAs. Among the control group of five women with tubal ligations, there was no detectable hCG above threshold with the IRMA. Thus, the enhanced sensitivity and specificity of the IRMA allows very early pregnancy losses to be identified that would otherwise be undetectable. Furthermore, its effectiveness with small quantities of first morning urine makes the IRMA a useful tool for epidemiologic studies.
We have developed a method of estimating day of ovulation using urinary ovarian hormone data. The method identifies a day of luteal transition that occurs at the shift from production of follicular oestrogen to luteal progesterone. The algorithm for identifying this shift was evaluated and judged better than specified alternatives in that it resulted in (1) a high concordance between the day of luteal transition and peaks in urinary luteinizing hormone (LH) for cycles with well-defined peaks, (2) a low variance in the length of the luteal phase of the menstrual cycle, which presumably reflects a low measurement error in estimating day of ovulation, and (3) a high proportion of cycles for which an approximate day of ovulation could be determined. To validate the new algorithm, it was applied to an independent data set. The algorithm identified a day of luteal transition in 88 percent of these cycles, and the identified day occurred within two days of the urinary LH peak for all of the cycles with clear LH peaks. Determination of the day of luteal transition to estimate ovulation requires only first-morning urine specimens, requires no correction for day-to-day variations in urine concentration, and can be applied to a mid-ycle window of data.
Human in vitro fertilization is characterized by a low of ficiency of implantation. Possible mechanisms for pregnancy loss are discussed. Embryo viability or quality, abnormal implantation, and delayed or absent corpus luteum rescue may all play a role in pregnancy wastage. Defining the possible mechanism for these losses may allow hormonal treatment to correct specific abnormalities.
4th Ed Bibliogr. na konci kapitol
Direct radioimmunoassay are described for the measurement of each of three specific estrogen glucosiduronates: estrone glucosiduronate, 17 beta-estradiol-17-glucosiduronate and estriol-16 alpha-glucosiduronate in urine. Each assay utilizes a specific antiserum prepared by complexing the carboxylic acid group of the appropriate glucosiduronate to the epsilon-amino group of lysine in bovine serum albumin or bovine thyroglobulin. The antisera showed little or no cross reactivity toward other estrogens that might be present in significant amounts in urine. These antisera were used for the direct assay of the conjugates in urine from normal men and nonpregnant women without prior extraction or chromatography. The values were similar to those obtained after extraction, chromatographic purification on DEAE-Sephadex and subsequent immunoassay; The following mean values +/- SE (microgram/g creatinine) were obtained: estrone glucosiduronate, male 10.1 +/- 0.6, follicular phase female 17.3+/- 1.6, luteal phase female 31.8 +/- 2.5; 17 beta-estradiol-17-glucosiduronate, male 1.7 +/- 0.3, follicular phase female 2.4 +/- 0.1, luteal phase female 4.2 +/- 0.4; estriol-16 alpha-glucosiduronate, male 1.8 +/- 0.2, follicular phase female 4.7 +/- 0.9, luteal phase female 10.0 +/- 1.6.
An antibody was prepared against pregnanediol-3α-glucuronide-BSA. The hapten (5β-pregnane-20α-ol-3α-yl-glucuronide) used for the preparation of the immunogen and as ‘cold’ standard for RIA was synthesized by an unambiguous chemical synthesis. The corresponding [6,7-3H]-labelled conjugate was prepared and the cross-reactions of the antiserum against other glucuronides and free steroids were examined. Application of RIA to menstrual cycle urines and pregnancy urine is discussed. The results of our own studies carried out throughout the menstrual cycle from seven women showed the mean and range for the follicular phase were 3.8 ± 0.67 (3.0 – 5.4) μmol/24 h and for the luteal phase 17.7 ± 6.9 (6.9 – 29.0) μmol/24h.
The WHO Expert Committee on Biological Standardization has established CR119 HCG, CR119 HCGα, and CR119 HCGβ3 as reference preparations for the immunoassay of human chorionic gonadotrophin (HCG) and its subunits. CR119 HCG has interstitial cell stimulating activities of 13 450 IU/mg (bioassay, Second International Standard for HCG) and proportional thyroid stimulating and follicle stimulating activities when tested in vivo. In the subunit preparations, the potencies of these activities are uniformly less than 0.02 relative to the undissociated hormone, and approximately 75% of the activity of each is recovered after recombination. The chemical, physical, and antigenic properties of each preparation are consistent with those reported for preparations of equivalent purity.
Human CG (hCG) was administered to three groups of four normally cycling women in the early luteal phase (LH +4 to +5, group I), the midluteal phase (LH +8 to +9, group II), and the late luteal phase (LH +11 to +12, group III). Two hundred and fifty IU hCG were given im followed in half of the subjects by 750 IU hCG 24 h later. Serial blood samples were then taken at 15- or 30-min intervals following either the first or second hCG injection and continued for 12 or 24 h. The samples were stored frozen at -20 C until assayed for LH, progesterone, estradiol, and hCG concentrations. Treatment with 250 IU hCG at each stage of the luteal phase did not result in any marked change in hormone concentrations. Further hCG administration (750 IU 24 h later) in both the early and the midluteal phases elicited a clear increase in progesterone concentrations. Further hCG treatment in the late luteal phase did not evoke any rise in progesterone levels. Further hCG administration in the midluteal phase resulted in a sharp decline in LH concentrations, brought about mainly by a decrease in LH pulse frequency, this response was not apparent at any other stage of the luteal phase. Despite the lack of any pulsatile steroidogenic stimulus at this time, progesterone was clearly secreted in a pulsatile manner. The decline in LH levels following hCG administration in the midluteal phase resembled that seen in spontaneous conception cycles following implantation. The restriction of this response to the time of normal implantation may suggest a role for the pituitary in the establishment of the "implantation window." The importance of this pituitary response and the mechanisms involved are currently unknown. Its absence in the early luteal phase would suggest that it cannot be directly attributed to either progesterone or hCG. It is possible that some other luteal factor may be responsible for the midluteal decline in LH concentrations.
Excerpt
Sheffield Fertility Centre, 26 Glen Road, Sheffield, S7 1RA, UK and University Department of Obstetrics and Gynaecology, Jessop Hospital for Women, Leavygreave Road, Sheffield, S3 7RE, UK
Keywords: implantation; in-vitro fertilization; pregnancy; pregnancy loss; human chorionic gonadotrophin; human
Introduction The endocrine characteristics of normal human pregnancy have been difficult to establish, chiefly because spontaneous pregnancies occur unpredictably. More reliable sources of early pregnancy data are conceptions following various assisted reproductive technologies although, unfortunately, many of these may not be useful for determining normal physiology, firstly, because there is multiple follicle development resulting from the use of exogenous gonadotrophins and, secondly, because human chorionic gonadotrophin (hCG) given to induce luteinization masks hCG from the implanting embryo. Furthermore, the practice, at least for in-vitro fertilization (IVF), of replacing up to 3 embryos renders assessment of the number of implantation sites uncertain.
In-vitro fertilization in the natural or spontaneous cycle may provide
Loss of a conceptus early in development can be detected by very sensitive assays specific for hCG. We examined 20 menstrual cycles ending in early loss of a conceptus in order to identify hormonal correlates of loss. Each loss cycle was compared to a successful conception cycle in the same woman, using daily concentration of urinary estrone-3-glucuronide and pregnanediol-3-glucuronide (PdG). The estrone-3-glucuronide and PdG profiles in cycles of early pregnancy loss were very similar to those in successful conception cycles until late in the luteal phase. Early pregnancy loss was not related to a midluteal deficiency in PdG. hCG tended to be detected later in cycles of early pregnancy loss than in successful conception cycles, presumably indicating later implantation. Ten of the early pregnancy losses implanted after luteal-day-10; only one of the successful pregnancies implanted that late. The corpus luteum responded to the conception in only 2 of the 10 loss cycles with late implantation. In contrast, the corpus luteum responded in 8 of 10 loss cycles with normally timed implantation. The similarity of preimplantation hormonal profiles in cycles of early pregnancy loss and in cycles with successful conceptions suggests that most early losses in reproductively normal women do not result directly from deficiencies in ovarian steroid production.
Human in vitro fertilization is characterized by a low efficiency of implantation. Possible mechanisms for pregnancy loss are discussed. Embryo viability or quality, abnormal implantation, and delayed or absent corpus luteum rescue may all play a role in pregnancy wastage. Defining the possible mechanism for these losses may allow hormonal treatment to correct specific abnormalities.
We looked at risk of early pregnancy loss among 171 women who conceived while participating in study. Twenty-five percent of biochemically detected pregnancies ended within six weeks of the last menstrual period; all but two of these losses were clinically unrecognized. While our sample is small, it is the first to allow description of possible associations between risk of early pregnancy loss and maternal characteristics or exposures. We looked at risk in relation to a woman's age, pregnancy history, weight, education, prenatal DES exposure, cigarette smoking, use of caffeinated and alcoholic beverages, marijuana, cigarette smoking by baby's father, and other variables. None of these factors was definitely associated with early pregnancy loss. Still, the possibility of real effects cannot be excluded and deserves further study.
Pregnancy rates vary considerably with the type of ovarian stimulation used for in vitro fertilization and embryo transfer (IVF-ET). The window of implantation may represent one of the rate-limiting steps in IVF success. We therefore investigated estimated implantation times of 10 consecutive IVF singleton pregnancies, achieved using pituitary suppression with gonadotropin-releasing hormone agonist (GnRH-a) before and during ovarian stimulation with human menopausal gonadotropins (hMG), and compared those with 9 consecutive IVF pregnancies achieved by hMG stimulation only. Estimated implantation times were calculated by regression analysis of serial human chorionic gonadotropin (hCG) measurements between days 7 and 16 after ET. The GnRH-a/hMG pregnancies implanted between days 7 and 11, whereas hMG pregnancies implanted between days 7 and 9 after ET. The hCG regression curve for the GnRH-a/hMG pregnancies revealed a delay of 1.5 days in estimated implantation time compared with the hMG only group. There were no significant differences in pretransfer in vitro embryos development between the two groups. Thus, the delay in hCG rise probably reflects a delay in embryo implantation. We therefore conclude that a GnRH-a/hMG stimulation protocol appears to widen the implantation window in comparison with a hMG only protocol. This observation may at least in part explain the improved IVF pregnancy success with GnRH-a/hMG stimulation protocols.
Paired blood and urine samples were obtained from patients between the sixth and 14th weeks of normal pregnancy. The levels of intact human chorionic gonadotropin (hCG), and of the free alpha and beta subunits, were measured by specific immunoassays. There was a close association between blood and urine levels of intact hCG and of the alpha subunit of hCG, but no relation between the levels of beta subunit in these sites. These findings suggest that the use of "beta subunit" assays may give discrepant results according to the fluid examined. By contrast, measurement of intact hCG appears to give similar results in blood and urine.
Human chorionic gonadotrophin beta (HCG-beta) is a trophoblast marker. Its expression is normally limited to syncytiotrophoblast cells of chorionic villi, although it is known to be secreted from the human embryo as early as 7 days post-fertilization. To examine the onset of embryonic transcriptional activity of the gene encoding this polypeptide we have performed in-situ hybridization to cellular RNAs of human tripronucleate preimplantation embryos. We see expression of HCG-beta RNA at the 6-8-cell stage, before morphological differentiation between trophectoderm and inner cell mass is apparent. We believe that this RNA is the product of de novo transcription from the embryonic genome, since transcripts are only observed in embryos of at least 2 days post-fertilization in age.
Following in vitro fertilization, the criteria commonly used to select human embryos for transfer are the cleavage rate and gross morphology, the contention being that those embryos which divide more rapidly and have regular, spherical blastomeres are more likely to lead to a pregnancy. In order to assess the validity of this assumption, the development in vitro of spare embryos was investigated. Eggs and embryos were cultured in Earle's balanced salt solution containing 10% heat-inactivated patient's serum, and insemination was performed at 40 hr post human chorionic gonadotropin (hCG). At 82-90 hr post hCG, up to four embryos were transferred. Any spare embryos were cultured in the same medium for up to 6 days and scored daily for cell number and morphology using a "quality" scale of 4-1 according to degree of fragmentation and shape of the blastomeres. Of 317 fertilized eggs, 55 (17%) developed to the fully expanded blastocyst stage. The remaining embryos ceased development at the one-cell (6; 2%), two-cell (49; 15%), four-cell (110; 35%), eight-cell (61; 19%), and cavitating morula (36; 11%) stages. The relationship between developmental arrest and gross morphology is discussed.
The receptivity for blastocyst implantation is controlled by progesterone and in some species by the synergistic action of progesterone and estrogen. The duration of the receptive phase, the so-called "window," is short in rodents (less than 24 hours) and may be three days in the primate. Once the uterus becomes receptive, it automatically becomes refractory at the end of the receptive phase. The uterus in the refractory phase can be toxic to the blastocyst in small laboratory animals. The endometrium of the receptive uterus may be characterized by the following parameters: (1) Formation of bulbous protrusions on the apical surface of the luminal epithelium; (2) Secretion of the stage-specific glycoproteins by the luminal epithelium; (3) Readiness of stromal cells to decidualize when appropriate stimulation is applied; and (4) Reorganization and changes of stromal extracellular matrix components so that stromal cells are conditioned for decidualization, and after decidualization the appearance of basement membrane components in the matrix.
We studied the risk of early loss of pregnancy by collecting daily urine specimens from 221 healthy women who were attempting to conceive. Urinary concentrations of human chorionic gonadotropin (hCG) were measured for a total of 707 menstrual cycles with use of an immunoradiometric assay that is able to detect hCG levels as low as 0.01 ng per milliliter, with virtually 100 percent specificity for hCG in the presence of luteinizing hormone. Our criterion for early pregnancy--an hCG level above 0.025 ng per milliliter on three consecutive days--was determined after we compared the hCG levels in the study group with the levels in a comparable group of 28 women who had undergone sterilization by tubal ligation. We identified 198 pregnancies by an increase in the hCG level near the expected time of implantation. Of these, 22 percent ended before pregnancy was detected clinically. Most of these early pregnancy losses would not have been detectable by the less sensitive assays for hCG used in earlier studies. The total rate of pregnancy loss after implantation, including clinically recognized spontaneous abortions, was 31 percent. Most of the 40 women with unrecognized early pregnancy losses had normal fertility, since 95 percent of them subsequently became clinically pregnant within two years.
We intensively studied 30 women attempting pregnancy in order to lay groundwork for larger studies of early pregnancy loss. These women collected first morning urine specimens for up to 6 months after discontinuing use of birth control. Urine specimens were successfully collected for 98% of the woman-days in the study. Three assays for human chorionic gonadotropin (hCG) were performed on each urine specimen. An immunoradiometric assay (IRMA) specific to the carboxyterminal peptide of the hCG beta-chain proved to be more sensitive and more specific than two radioimmunoassays (RIAs). Using the IRMA, we found four cases in which hCG rose and fell over successive days, consistent with early pregnancy loss. For three of these four cases, the level of hCG was too low to be detectable with the RIAs. Among the control group of five women with tubal ligations, there was no detectable hCG above threshold with the IRMA. Thus, the enhanced sensitivity and specificity of the IRMA allows very early pregnancy losses to be identified that would otherwise be undetectable. Furthermore, its effectiveness with small quantities of first morning urine makes the IRMA a useful tool for epidemiologic studies.
A highly sensitive and specific two-site immunoradiometric assay (IRMA) for hCG has been developed and applied to the detection of the hormone in the urine of normal nonpregnant and pregnant individuals. The IRMA uses a solid phase coupled monoclonal antibody to the hCG beta-subunit for extraction of hormone from urine. The hCG extracted is then directly quantified by the binding of an affinity purified and radiolabeled rabbit antibody that reacts with the unique COOH-terminal peptide region of the hCG beta-subunit. The assay is capable of reliably and accurately measuring as little as 0.01 ng hCG/ml urine without interference from hLH. Assays of urine from normal men and nonpregnant women of reproductive age indicated that most individuals did not have detectable levels of hCG immunoreactivity, although a minority had minute amounts, with a mean value of approximately 0.01 ng hCG/mg creatinine. In contrast, all normal menopausal women studied had easily detectable levels of hCG immunoreactivity in their urine, with a mean value of 0.123 ng hCG/mg creatinine. A study of the excretion of hCG from three men injected with hormone for treatment of infertility indicated that after the first 24 h, hCG was cleared with a single exponential rate and was detectable to a level of 0.01 ng/ml. Application of the IRMA to measurements of hCG in the urine of two artificially inseminated patients indicated that the method was capable of detecting pregnancy as early as 9 days postovulation. The extreme sensitivity and specificity of the IRMA for urinary hCG in conjunction with the simplicity of assay performance and specimen collection should provide a substantial advantage over currently available methods for detection of early pregnancy and tumor monitoring.
The preimplantation effects of progesterone antagonists on the cell biology of the endometrium, corpus luteum function and interactions between these two organs have been studied. The antagon ists lilopristone (ZK 98.734) and onapristone (ZK 98.299) were initially given per os to rabbits early or late in pseudopregnancy in combination with human chorionic gonadotrophin (HCG). These protocols were then modified to include hysterectomy or luteotrophic support with 17β-oestradiol. Given alone, the antagonists gave rise to endometrial regression (inhibition of epithelial proliferation and differentiation, increase of apoptosis). The simultaneous addition of oestradiol did not alter these findings. A rapid luteolysis occurred when the antagonists were given in late pseudopregnancy, but not if combined with oestradiol or hysterectomy. The endometrium was capable of renewal and of sustaining implantation if the corpora lutea survived or oestradiol was administered, and transferred blastocysts displayed normal implantation and normal embryonic development. These events did not occur when the antagonists were given during late pseudopregnancy without any steroid supplement.
Progesterone antagonists can evidently exert a direct inhibitory effect on the endometrium, possibly with a later indirect luteolytic effect via endometrial mediators. Simultaneous addition of a proper luteotrophic signal results in corpora lutea which are refractory to lysis, so revealing a potential functional dissociation between endometrium and corpus luteum. The endometrium has the capacity to differentiate normally after an interrupted transformation and becomes receptive and sustains normal pregnancy, due to an expanded lifespan of the corpora lutea and a transposition of the implantation window. Uterine secretions from patients undergoing in-vitro fertilization, collected at the onset of the luteal phase, were evaluated by SDS-PAGE densitometry. The protein profiles gave indications of an adequate luteal phase pattern and of a receptive preimplantation phase. These results open the prospect of manipulating the human implantation window.
To examine whether opening of the zona pellucida (i.e., assisted hatching) accelerates implantation.
In a controlled, randomized trial, patients were assigned to control and assisted hatching groups.
All patients studied were of the Center for Reproductive Medicine at Cornell University Medical College.
All patients underwent stimulation with gonadotropins after luteal phase GnRH down regulation. Assisted hatching with zona drilling using acidic Tyrode's solution was performed on the assigned embryos.
Luteal E2, P, and hCG on days +5, +6, +7, +8, +9, +11, +13, and +15 were measured. The implantation time, peak midluteal E2 and intervals between these two values were studied.
Implantation occurred significantly earlier in the assisted hatching group. The interval between implantation and peak midluteal E2 was also significantly shorter in the assisted hatching group than in the controls. However, there was no significant difference in the day of the peak midluteal E2 between the assisted hatching and control groups.
Assisted hatching may enhance embryo implantation not only by mechanically facilitating the hatching process but also by allowing earlier embryo-endometrium contact. Such early contact may enhance embryonic development potential and may optimize synchronization between embryo and endometrium, resulting in improved implantation efficiency.
Of 48 spare human pre-embryos achieving the expanded blastocyst stage, 22 (45.6%) secreted significant amounts of human chorionic gonadotrophin (HCG) (> 5 IU/l/day). Of these, nine remained intrazonal, seven partially hatched and six fully hatched. Embryonic production of HCG in vitro appeared to be time-dependent, starting after a certain minimum time (approximately 160 h post-insemination) and rising exponentially, with maximal HCG production around day 10. Hatching was not a prerequisite for HCG secretion, since similar amounts were produced by intrazonal blastocysts. Blastocysts derived from abnormally fertilized oocytes also began secreting HCG exponentially but secretion was delayed and the upper limit of maximum HCG secretion rate was comparatively low. The actual amount of HCG is thought to reflect the number of viable trophectoderm cells producing the hormone. HCG doubling times for blastocysts in vitro were rapid when compared to implanting blastocysts of a similar age in vivo, with 19/22 (86.4%) blastocysts having a doubling time of < 10 h. Provided a pre-embryo can secrete HCG and maintain an adequate doubling time, sufficient HCG should be produced for initial stages of embryonic recognition in vivo. Since intrazonal blastocysts are capable of fulfilling both of these criteria, the limiting factor in realizing their full potential may be escaping from the zona pellucida.
Objective:
We determined the ovarian response to human chorionic gonadotrophin (hCG) in terms of relaxin and progesterone secretion during the peri-implantation period of normal and failing pregnancies. We wished to test the hypotheses that relaxin production in failing pregnancies is different from that in normal pregnancies, that relaxin is a reliable, quantitative indicator of the biological activity of endogenous hCG, and that relaxin is a useful predictor of peri-implantation spontaneous abortions.
Design:
Daily blood samples were collected in a prospective longitudinal study from insemination patients.
Patients:
Women undergoing artificial insemination in natural cycles with non-frozen donor semen at a University clinic.
Measurements:
Serum LH, hCG, relaxin and progesterone were measured and the relationship between hCG and the ovarian hormones was evaluated in the peri-implantation period of normal pregnancies and spontaneous abortions.
Results:
Nine of 23 conceptive cycles resulted in a spontaneous abortion between 16 and 70 days after the LH peak. In all normal and failing pregnancies there was a close qualitative relationship between hCG secretion and relaxin production. Six of nine failing pregnancies were associated with abnormally low hCG secretion. Six of the spontaneous abortions were associated with rates of relaxin secretion which were higher than the mean of 14 normal pregnancies. No such alterations in progesterone concentrations were observed. In cases where hCG was extremely low, the quantitative relationship between hCG and relaxin was different from that in cases of normal hCG concentrations.
Conclusions:
There is a close temporal relationship between the secretion of trophoblastic hCG and ovarian secretion of relaxin in the peri-implantation period of normal and failing pregnancies. In failing pregnancies there is substantial variability in the quantitative relationship between relaxin and hCG, indicating that relaxin is not a reliable quantitative indicator of hCG bioactivity. Contrary to previous reports, relaxin concentrations in failing pregnancies tended to be higher than or equal to concentrations in normal pregnancies until the loss was imminent. Because of this relaxin is not a useful predictor of peri-implantation spontaneous abortions.
Longitudinal epidemiologic studies of menstrual and reproductive function are more informative if one can identify day of ovulation. We previously developed a method for estimating day of ovulation that is feasible for epidemiologic studies. The method relies on the relative concentrations of estrogen and progesterone metabolites in daily first-morning urine specimens and does not require creatinine adjustment. This paper describes results of applying this method to a large study with 724 menstrual cycles from 217 women. The method estimated a credible day of ovulation in 88% of cycles. Missing data accounted for most of the failures. When we excluded anovulatory cycles (1%) and cycles with missing data, the method estimated a day of ovulation in 97% of cycles. Variance in luteal phase length was small for our sample, suggesting that this method of identifying a day of ovulation introduces no more measurement error than when day of ovulation is determined by plasma luteinizing hormone (LH), the standard clinical method.
Embryo implantation involves a series of complex interactions between the developing embryo and the maternal endometrium. Results of studies with animal models suggest that the uterus must undergo a series of morphological and biochemical changes, mediated primarily by oestrogen and progesterone, before it becomes receptive for successful implantation. At present there is little understanding of the endometrial changes required to achieve endometrial receptivity for implantation in the human. It appears that control of receptivity is not as stringent in the human as in some other species, with IVF data suggesting that the duration of receptivity is at least 4 days, and that successful implantation can occur under a relatively wide range of morphological and ultrastructural conditions. Research on the later stages of implantation, including embryo positioning within the uterus, attachment and invasions, has been almost non-existent in the human. Further studies are critical for a better understanding of this complex process, although human studies will always be limited by ethical constraints.
To gain insight into the physiology of human endometrial development after artificial preparation with estrogen (E) and P, before oocyte donation.
Review and analysis of relevant studies published in the last decade, identified through the literature and Medline searches.
Oocyte donation represents a unique in vivo experimental model in the human that permits the study of endometrial development under controlled variable conditions. Early studies have shown that adequate endometrial preparation can be achieved by sequential E and P only. The successful implementation of the simplified approach to oocyte donation demonstrated that satisfactory endometrial receptivity is not dependent on incremental administration of E and P and similarly can be achieved by fixed dosages of these steroids. Moreover, numerous clinical oocyte donation studies have shown that both physiologic and supraphysiologic levels of E and P have resulted in good endometrial development and pregnancy rates, underlining the relative insensitivity of the endometrium to extreme hormonal conditions. In addition, it has been clarified that the endometrium is tolerant of some manipulations during the follicular phase. Contrary to morphological studies that demonstrated preservation of endometrial preparation after luteal E depletion, preliminary evidence suggests that the functional capacity of the endometrium could be affected adversely.
In contrast to early oocyte donation studies, which indicated a correlation between morphologic integrity and functional capacity of the endometrium, some evidence presented in this review demonstrates that adequate endometrial morphology does not always imply normal endometrial receptivity.
Integrins belong to a family of cell adhesion molecules that are present on virtually all cells. The temporal and spatial expression of these important proteins on the human endometrium suggests that certain integrins may participate in the cascade of molecular events leading to successful implantation.
Using immunohistochemistry, we studied the expression of 12 different integrins in up to 600 samples of human endometrium throughout the menstrual cycle. Intensity and distribution of staining was determined using the semiquantitative HSCORE, with specific focus on the differences between glandular and luminal expression.
We noted that the glandular and luminal epithelium undergo independent alterations in integrin expression throughout the menstrual cycle. Specifically, glandular epithelium express certain integrins only during the window of implantation, while luminal epithelium down-regulate certain integrins during this time. The expression of one integrin (the alpha v beta 3 vitronectin receptor) on both luminal and glandular epithelium coincides with the time of embryo attachment; aberrant expression of this integrin is associated with infertility.
It appears that the endometrium is a unique tissue with regard to the number of integrins that undergo temporal and spatial changes during the menstrual cycle. These data may offer new directions for the development of a novel contraceptive approach targeted to the endometrium as well as a better understanding of occult causes of infertility in women.
As implantation approaches the different endometrial components demonstrate certain anatomical and molecular changes. Molecules with an effect on uterine receptivity for blastocyst implantation include integrins, leukaemia inhibitory factor (LIF), interleukin-1 (IL-1) and colony stimulating factor-1 (CSF-1). Although over the past 5 years our understanding of the implantation process has improved dramatically, there are still many unanswered questions. Undisputed morphological, biochemical and molecular markers of uterine receptivity that permit quantification of the human implantation window are still unknown. The factors which regulate the expression of integrins, LIF, CSF-1 and IL-1, the mode of action of these molecules and their role in human implantation remain unclear. Only when these questions are answered shall we be able to apply the molecular aspects of implantation to clinical practice.
From a study of 34 early human ova (24 normal and 10 abnormal) recovered from a series of 107 patients known to be fertile whose conditions for conception were optimal it appears that the maximum fertility rate at implantation is 58%; the maximum normal fertility rate after the twelfth day of ovular development is 42%; the probable maximum fertility rate during the preimplantation stages is from 80 to 90%; the greatest ovular loss is in the preimplantation stage; the next greatest loss is during the week after implantation; the ovular loss after the first missed period may be as great as 28.6%, either with or without clinical signs and is therefore comparable to the clinical abortion rate; these defective human fertilized ova rise because of intrinsic defects rather than from defects of the local or endocrine environment, and, finally, the fertility rates and fate of fertilzed ova are roughly comparable in man and other mammals.
Endometrial preparation: lessons from oocyte donation Klentzeris LD. The role of endometrium in implantation
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