The association of maternal factors with delayed implantation and the initial rise of human chorionic gonadotrophin

Epidemiology Branch, National Institute of Environmental Health Sciences, PO Box 12233, MD A3-05, Durham, NC 27709, USA.
Human Reproduction (Impact Factor: 4.57). 02/2011; 26(4):920-6. DOI: 10.1093/humrep/der009
Source: PubMed


BACKGROUND Late implantation and the pattern of early rise in hCG have been associated with early pregnancy loss. We explored factors
that might be predictive of these markers of poor embryonic health in spontaneously conceived pregnancies.

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    • "The literature on fetal loss suggests that selection against less fit male fetuses may extend later in gestation than that against females. An estimated 25% of implanted (i.e., hCG-producing) gestations end within 6 weeks of implantation (Wilcox et al. 1999; Jukic et al. 2011). Female fetuses with chromosomal abnormalities predominate among these early abortuses (Evdokimova et al. 2000; Boklage 2005). "
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    ABSTRACT: Evolutionary theory, when coupled with research from epidemiology, demography, and population endocrinology, suggests that contracting economies affect the fitness and health of human populations via natural selection in utero. We know, for example, that fetal death increases more among males than females when the economy unexpectedly contracts; that unexpected economic contraction predicts low secondary sex ratios; and that males from low sex ratio birth cohorts live, on average, longer than those from high sex ratio cohorts. We also know that low levels of human chorionic gonadotropin (i.e., hCG) measured in the serum of pregnant women predict fetal death. We do not, however, know whether male survivors of conception cohorts subjected to contracting economies exhibit, as theory predicts, higher hCG than those from other cohorts. We show, in 71 monthly conception cohorts including nearly two million California births, that they do. We thereby add to the literature suggesting that the economy, a phenomenon over which we collectively exercise at least some control, affects population health. Our findings imply that the effect arises via natural selection - a mechanism we largely ignore when attempting to explain, or alter, how collective choice affects our biology.
    Full-text · Article · Dec 2012 · Evolutionary Applications
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    ABSTRACT: In oocyte donation cycles where hormone replacement is given to recipients, progesterone administration is necessary to induce the luteal phase and synchronize the endometrium with the embryo stage. Most studies suggest that 5-7days of progesterone are needed to prepare the endometrium for a day-5 embryo transfer and provide optimal implantation rate. This paper reports a case where an agonadal oocyte recipient received only 2days of progesterone prior to the embryo transfer of a day-5 embryo. She subsequently had a clinical pregnancy and a live birth.
    No preview · Article · Jun 2012 · Reproductive biomedicine online
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    ABSTRACT: How variable is the length of human pregnancy, and are early hormonal events related to gestational length? Among natural conceptions where the date of conception (ovulation) is known, the variation in pregnancy length spanned 37 days, even after excluding women with complications or preterm births. Previous studies of length of gestation have either estimated gestational age by last menstrual period (LMP) or ultrasound (both imperfect measures) or included pregnancies conceived through assisted reproductive technology. The Early Pregnancy Study was a prospective cohort study (1982-85) that followed 130 singleton pregnancies from unassisted conception to birth, with detailed hormonal measurements through the conception cycle; 125 of these pregnancies were included in this analysis. We calculated the length of gestation beginning at conception (ovulation) in 125 naturally conceived, singleton live births. Ovulation, implantation and corpus luteum (CL) rescue pattern were identified with urinary hormone measurements. We accounted for events that artificially shorten the natural length of gestation (Cesarean delivery or labor induction, i.e. 'censoring') using Kaplan-Meier curves and proportional hazards models. We examined hormonal and other factors in relation to length of gestation. We did not have ultrasound information to compare with our gold standard measure. The median time from ovulation to birth was 268 days (38 weeks, 2 days). Even after excluding six preterm births, the gestational length range was 37 days. The coefficient of variation was higher when measured by LMP (4.9%) than by ovulation (3.7%), reflecting the variability of time of ovulation. Conceptions that took longer to implant also took longer from implantation to delivery (P = 0.02). CL rescue pattern (reflecting ovarian response to implantation) was predictive (P = 0.006): pregnancies with a rapid progesterone rise were longer than those with delayed rise (a 12-day difference in the median gestational length). Mothers with longer gestations were older (P = 0.02), had longer pregnancies in other births (P < 0.0001) and were heavier at birth (P = 0.01). We did not see an association between the length of gestation and several factors that have been associated with gestational length in previous studies: body mass index, alcohol intake, parity or offspring sex. The sample size was small and some exposures were rare, reducing power to detect weak associations. Human gestational length varies considerably even when measured exactly (from ovulation). An individual woman's deliveries tend to occur at similar gestational ages. Events in the first 2 weeks after conception are predictive of subsequent pregnancy length, and may suggest pathways underlying the timing of delivery. This research was supported by the Intramural Research Program of the NIH, National Institute of Environmental Health Sciences. None of the authors has any conflict of interest to declare.
    Preview · Article · Aug 2013 · Human Reproduction
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