Ernest Ng

• The University of Hong Kong

We present two cases of suspected intramural pregnancy after failed intervention for ‘miscarriage’ of an initially presumed normally sited pregnancy. The diagnosis of intramural pregnancy was assumed retrospectively after taking into consideration the whole clinical picture. These cases illustrate the difficulty in early diagnosis and further confi...

Background Manual counting for semen analysis is recommended by the World Health Organization. Technicians performing this usually record their results on a paper worksheet and then enter the data into an electronic laboratory information system. One disadvantage of this approach is the chance of post-analytical transcription errors, which can be r...

Background This study aims to investigate the association of pre-conception vitamin D levels on adverse pregnancy outcomes in women undergoing in vitro fertilization with fresh embryo transfer. Methods This was a retrospective cohort study using archived serum 25-hydroxyvitamin D measured in the pre-conception period before ovarian stimulation in...

Purpose To assess the association of serum vitamin D level and the live birth rate in women undergoing frozen embryo transfer (FET). Methods This is a retrospective cohort study involving 1489 infertile women who had frozen embryo transfer at two tertiary reproductive medicine centres from 2019 to 2021. Only the first frozen embryo transfer was in...

Background Levonorgestrel (LNG) acts as an emergency contraceptive mainly by inhibiting or postponing ovulation. We carried out this study to investigate whether LNG at concentration relevant for emergency contraception (EC) affect ciliary beat frequency and muscular contraction of the human Fallopian tube, which might contribute additional actions...

B cells constitute a diverse and adaptable immune cell population with functions that can vary according to the environment and circumstances. The involvement of B cells in pregnancy, as well as the associated molecular pathways, has yet to be investigated. This review consolidates current knowledge on B cell activities and regulation during pregna...

Background At menstruation, the functional layer of the human endometrium sheds off due to the trigger of the release of inflammatory factors, including interleukin 6 (IL-6), as a result of a sharp decline in progesterone levels, leading to tissue breakdown and bleeding. The endometrial mesenchymal stem-like cells (CD140b⁺CD146⁺ eMSC) located in th...

Introduction Low vitamin D status is prevalent among women with polycystic ovary syndrome (PCOS). The objective of the study is to assess the effect of vitamin D supplementation on (1) the ovulation rate to letrozole and (2) other reproductive, endocrine and metabolic outcomes after 1 year of supplementation in women with PCOS. Methods and analysi...

Introduction Chemotherapy is crucial in treating gestational trophoblastic neoplasia (GTN), but its impact on gonadotoxicity is unclear. Materials and Methods This case–control study included 57 GTN patients and 19 age‐matched patients with molar pregnancies (MP) in 2012–2018. Multiples of the median (MoM) of the serum AMH levels were compared bet...

Introduction Progestin can inhibit the pituitary luteinising hormone (LH) surge during ovarian stimulation for in vitro fertilisation (IVF) and studies show progestin-primed ovarian stimulation (PPOS) is effective in blocking the LH surge in IVF. More and more centres are using PPOS because this regimen appears simpler and cheaper. This study aims...

Background The monthly regeneration of human endometrial tissue is maintained by the presence of human endometrial mesenchymal stromal/stem cells (eMSC), a cell population co-expressing the perivascular markers CD140b and CD146. Endometrial regeneration is impaired in the presence of intrauterine adhesions, leading to infertility, recurrent pregnan...

Background and Aims: In the Rotterdam criteria (2003), polycystic ovary morphology for diagnosing polycystic ovary syndrome (PCOS) was defined as an antral follicle count (AFC) of 12 or more (or ovarian volume of 10 cc or more) in either ovary. In the international guideline (2018), the AFC threshold was increased to 20. We compared the metabolic r...

This study aimed to optimize the non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) in the laboratory by comparing two collection timing of the spent culture medium (SCM), two embryo rinsing protocols, and the use of conventional insemination instead of intracytoplasmic sperm injection (ICSI). Results of two embryo rinsing method...

Early-onset preeclampsia (EOPE) is a severe pregnancy complication associated with defective trophoblast differentiation and functions at implantation, but manifestation of its phenotypes is in late pregnancy. There is no reliable method for early prediction and treatment of EOPE. Adrenomedullin (ADM) is an abundant placental peptide in early pregn...

BACKGROUND The establishment of maternal–fetal crosstalk is vital to a successful pregnancy. Glycosylation is a post-translational modification in which glycans (monosaccharide chains) are attached to an organic molecule. Glycans are involved in many physiological and pathological processes. Human endometrial epithelium, endometrial gland secretion...

Severe endometrium damage causes pathological conditions such as thin endometrium and intrauterine adhesion, resulting in uterine factor infertility. Mesenchymal stem cell (MSC) therapy is a promising strategy in endometrial repair, yet exogenous MSCs still raise concerns for safety and ethical issues. Human adipose-derived mesenchymal stem cells (...

Introduction The success rate of in vitro fertilisation (IVF) treatment for couples with infertility remains low due to lack of a reliable tool in selecting euploid embryos for transfer. This study aims to compare the efficacy in embryo selection based on morphology alone compared with non-invasive preimplantation genetic testing for aneuploidy (ni...

Human fallopian tubes (FTs) play important roles in the whole reproductive process. FTs are the site for the final maturation of gametes, fertilization, transport of preimplantation embryos, and early embryonic development before entering the uterus. All these functions are critical in the establishment of a successful pregnancy. When the embryo is...

Study question What are the characteristics of leptin receptor (LepR) expressing cells within the endometrial mesenchymal stromal/stem cells (eMSCs) population? Summary answer LepR+ eMSCs display better stem-cell capacities as well as distinctively quiescent properties compared to eMSCs and LepR- eMSCs. What is known already Single-cell RNA seque...

Study question Are cell surface proteins on trophoblastic spheroid BAP-EB derived from hEPSC involved in the endometrial epithelial cell attachment? Summary answer E-cadherin (CDH1) and Neuropilin-1 (NRP1) are two potential embryonic surface molecules involved in the human implantation process. What is known already Study of the mechanisms of hum...

Background: An effective and safe treatment for nausea and vomiting of pregnancy (NVP) is lacking. Objective: To assess the efficacy and safety of acupuncture, doxylamine-pyridoxine, and a combination of both in women with moderate to severe NVP. Design: Multicenter, randomized, double-blind, placebo-controlled, 2 × 2 factorial trial. (Clinica...

Background: In IVF/ICSI treatment, the process of embryo implantation is the success rate-limiting step. Endometrial scratching has been suggested to improve this process, but it is unclear if this procedure increases the chance of implantation and live birth (LB) and, if so, for whom, and how the scratch should be performed. Objective and ration...

Breast cancer is the most common cancer in reproductive age women. The aim of this study is to assess the knowledge, attitude and intention on fertility preservation among women diagnosed to have breast cancer. This is a multi-centre cross-sectional questionnaire study. Reproductive age women diagnosed with breast cancer attending Oncology, Breast...

Abstract Background To evaluate the association of serum advanced glycation end-products (AGEs) and its soluble receptor of AGE (sRAGE) levels with dysglycaemia and metabolic syndrome in women with polycystic ovary syndrome (PCOS). Methods This was an analysis of a cohort of women with PCOS who were prospectively recruited for a longitudinal observ...

Human fertilization begins when a capacitated spermatozoon binds to the zona pellucida (ZP) surrounding a mature oocyte. Defective spermatozoa-ZP interaction contributes to male infertility and is a leading cause of reduced fertilization rates in assisted reproduction treatments (ARTs). Human ejaculate contains millions of spermatozoa with varying...

Despite advances in in vitro fertilization (IVF), there is still a lack of non-invasive and reliable biomarkers for selecting embryos with the highest developmental and implantation potential. Recently, small non-coding RNAs (sncRNAs) have been identified in biological fluids, and extracellular sncRNAs are explored as diagnostic biomarkers in the p...

Purpose To evaluate the effect of basal serum testosterone levels on the ovarian response and the cumulative live birth rate of infertile women undergoing in vitro fertilization (IVF). Methods It is a retrospective study in a university-affiliated assisted reproduction center in Hong Kong. Infertile women undergoing the first IVF cycle in the cent...

In brief: Implantation failure can occur even after the transfer of good-quality embryos. This study showed that the migration of human endometrial stromal cells towards embryonic trophoblasts is higher in women with live births in the first in vitro fertilization cycle than those with repeated implantation failure, suggesting that the chemotactic...

Importance: Reducing maternal mortality is a global objective. The maternal mortality ratio (MMR) is low in Hong Kong, China, but there has been no local confidential enquiry into maternal death, and underreporting is likely. Objective: To determine the causes and timing of maternal death in Hong Kong and identify deaths and their causes that we...

Objective: To compare the inter-cycle variation of serum anti-Mullerian hormone (AMH) and antral follicle count (AFC) measurements over four consecutive menstrual cycles. Design: Observational study with secondary analysis using data from 2 previous randomised controlled trial PARTICIPANTS: 78 women from two previous randomised trials on the eff...

Ovulation induction is a first-line medical treatment for infertility in polycystic ovary syndrome (PCOS). Poor ovulation responses are assumed to be due to insulin resistance and hyperandrogenism. In a prospective cohort (PCOSAct) of 1000 infertile patients with PCOS, whole-exome plus targeted single-nucleotide polymorphism (SNP) sequencing and co...

During implantation, a symphony of interaction between the trophoblast originated from the trophectoderm of the implanting blastocyst and the endometrium leads to a successful pregnancy. Defective interaction between the trophoblast and endometrium often results in implantation failure, pregnancy loss, and a number of pregnancy complications. Owing...

In vitro fertilization is an effective treatment for various causes of infertility. However, management of women with poor ovarian response or premature ovarian insufficiency remains challenging because these women have under-developed small ovarian follicles that do not respond to hormone treatment. In vitro activation of small follicles has been...

Background: Reducing maternal and perinatal mortality is a global objective. Hong Kong is a city with low maternal and perinatal mortality but little is known about the trend and causes of these deaths in this high-income city. We analyzed the maternal death, stillbirth and neonatal death since 1946 in Hong Kong. Methods: Data were extracted fro...

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters cells via receptor angiotensin-converting enzyme 2 (ACE2) and co-receptor transmembrane serine protease 2 (TMPRSS2). However, patients with SARS-CoV-2 infection receiving ACE1 inhibitors had higher ACE2 expression and were prone to poorer prognostic outcomes. Until now, informa...

The original article [1] noted two erroneous grant numbers which have both since been corrected.

Human endometrium is an incredibly dynamic tissue undergoing cyclic regeneration and shedding during a woman’s reproductive life. Endometrial mesenchymal stromal/stem-like cells (eMSC) contribute to this process. A hypoxic niche with low oxygen levels has been reported in multiple somatic stem cell types. However, the knowledge of hypoxia on eMSC r...

Introduction In vitro fertilisation (IVF) is an effective infertility treatment but the live birth rate remains unsatisfactory. Ovarian stimulation by follicle-stimulating hormone (FSH) is routinely used in IVF and the resulting high serum estradiol levels may impair oocyte/embryo quality and endometrial receptivity. Letrozole, an aromatase inhibit...

Background: The maternal immune system needs to tolerate the semi-allogeneic fetus in pregnancy. The adaptation occurs locally at the maternal-fetal interface as well as systemically through the maternal circulation. Failure to tolerate the paternal antigens may result in pregnancy complications, such as pregnancy loss and pre-eclampsia. However,...

Endometrial mesenchymal stem-like cells (eMSC) reside in the basal layer of the endometrium and are responsible for cyclic regeneration during the reproductive lives of women. Myometrial cells act as a component of the niche and regulate the stem cell fate through the activation of WNT/β-catenin signaling via WNT5A. Since WNT5A-responsive mechanism...

Background: Human endometrium undergoes cycles of regeneration in reproductive women and endometrial mesenchymal stromal/stem like cells (eMSC) contribute to this process. Notch signaling is essential for the homeostasis of somatic stem cells, however its role in eMSC remains largely unknown. Methods: RT-qPCR was used to compare the activity of Not...

Objective: Vitamin D receptors are present in the female reproductive tract. Studies on the association between serum vitamin D level and pregnancy rate of in vitro fertilization (IVF) showed inconsistent results and focused on a single fresh or frozen embryo transfer cycle. The objective of our study was to evaluate if serum vitamin D level before...

Objective With the surge of confirmed cases of coronavirus disease 2019 (COVID-19) and its associated morbidities and mortalities, continuous companion support during labour was halted in all public hospitals in Hong Kong to prevent the spread of the virus in hospitals. The purpose of this retrospective study was to evaluate the effect of not havin...

STUDY QUESTION Does acupuncture improve insulin sensitivity more effectively than metformin or sham acupuncture in women with polycystic ovary syndrome (PCOS) and insulin resistance (IR)? SUMMARY ANSWER Among women with PCOS and IR, acupuncture was not more effective than metformin or sham acupuncture in improving insulin sensitivity. WHAT IS KNO...

Background Acupuncture reduces pain levels in many painful conditions. This study compared pain levels during surgical termination of first trimester pregnancy by suction evacuation (SE) under local analgesia with and without the use of acupuncture. Methods In all, 60 nulliparous women undergoing SE before 10 weeks of gestation were randomly assig...

Background In vitro fertilization (IVF) is a well-established method to treat various causes of infertility. Some previous retrospective studies suggested a lower ovarian response in Asian women compared to Caucasian women. However, the ovarian stimulation regimens were not standardized, potentially confounding the findings. The objective of this s...

Background The mechanism of action of a contraceptive method is an importantg consideration in a woman’s choice of contraception. For the development of new methods of contraception it is important to understand the acceptability of different contraceptive mechanisms within a population. Methods We recruited women attending contraceptive, terminat...

Sperm selection in the female reproductive tract (FRT) is sophisticated. Only about 1,000 sperm out of millions in an ejaculate reach the fallopian tube and thus have a chance of fertilizing an oocyte. In assisted reproduction techniques, sperm are usually selected using their density or motility, characteristics that do not reflect their fertiliza...

Bisphenol A (BPA) is a well-known endocrine disruptor, widely used in various consumer products and ubiquitously found in air, water, food, dust, and sewage leachates. Recently, several countries have restricted the use of BPA and replaced them with bisphenol S (BPS) and bisphenol F (BPF), which have a similar chemical structure to BPA. Compared to...

Increasing evidence shows that polycystic ovary syndrome (PCOS) patients are particularly vulnerable to anxiety/depression-like behaviors. This study sought to determine the prevalence of anxiety/depression-like behaviors among women with PCOS and to identify factors associated with these behaviors. This study was a secondary analysis of three stud...

Non-obstructive azoospermia (NOA) and diminished ovarian reserve (DOR) are two disorders that can lead to infertility in male and female. Genetic factors have been identified to contribute to NOA and DOR. However, the same genetic factor that can cause both NOA and DOR remains largely unknown. To explore the candidate pathogenic gene that cause bot...

Lack of awareness regarding the risk of hepatitis B virus (HBV) infection and the interventions available during pregnancy among the pregnant carriers may influence their willingness and adherence to the management. This study assessed the knowledge, perception and expectation of HBV infection among pregnant HBV carriers in Hong Kong. A prospective...

In this study, we used a network meta-analysis (NMA) to compare the effectiveness of medicines and supplements for idiopathic male infertility and to identify the best treatment. Medline, Excerpta Medica Database (EMBASE), Ovid, and China National Knowledge Infrastructure (CNKI), were searched for the period from January 1990 to June 2021 using the...

Study question: Is there any difference in the ongoing pregnancy rate after immediate versus delayed frozen embryo transfer (FET) following a stimulated IVF cycle? Summary answer: Immediate FET following a stimulated IVF cycle produced significantly higher ongoing pregnancy and live birth rate than did delayed FET. What is known already: Embry...

Objective To compare the effects of hyaluronic acid (HA)–enriched transfer medium versus standard medium on live birth rate after frozen embryo transfer (FET). Design Randomized, double-blind, controlled trial. Setting Two tertiary fertility centers. Patient(s) Infertile women aged <43 years at the time of in vitro fertilization undergoing FET....

STUDY QUESTION Will use of oral progestogen in women with threatened miscarriage in the first trimester reduce the miscarriage rate when compared with placebo? SUMMARY ANSWER Use of oral progestogen in women with threatened miscarriage in the first trimester did not reduce miscarriage before 20 weeks when compared with placebo. WHAT IS KNOWN ALRE...

The objective of this study was to evaluate the performance of ovarian response prediction index (ORPI) in predicting ovarian response and livebirth of women undergoing their first in-vitro fertilisation (IVF) cycle. This is a retrospective analysis of 285 women from 2013 to 2016. The outcome measures were area (AUC) under the receiver-operator cha...

Objective This study investigated the role of women’s age, serum anti-Müllerian hormone (AMH) level and semen parameters in predicting fecundability. Methods This was a prospective cohort study on couples attending for preconceptional health check. Occurrence of conception at 1 year after ceasing contraception and time to pregnancy were noted by t...

Serum anti-Mullerian hormone (AMH) levels are significantly higher in women with polycystic ovary syndrome (PCOS) than in normal ovulatory women. Different diagnostic cut-off values of AMH for discriminating women with PCOS from normal controls have been proposed. This is attributed partly to the different assay methods used with different calibrat...

Objective To study the use of human embryonic stem cell–derived trophoblastic spheroids (BAP-EB) as human blastocyst surrogates for studying early implantation and trophoblast development. Design Laboratory study. Setting University research laboratory. Patient(s) Infertile in vitro fertilization patients donating endometrial aspirates and human...

Objective To test the hypothesis that acupuncture improves insulin sensitivity in women with polycystic ovary syndrome (PCOS) and insulin resistance (IR). Design Prospective pilot study. Setting Guangzhou, China, 2014–2016. Participants Eighty women with PCOS aged 18–40 years with body mass index (BMI) above 18.5 kg/m ² and with homeostatic mode...

Research question Is fentanyl and midazolam non-inferior to pethidine and diazepam in pain relief during oocyte retrieval under conscious sedation? Design A randomized double-blinded non-inferiority trial of 170 infertile women undergoing oocyte retrieval under conscious sedation in an assisted reproduction centre. The women were randomized to rec...

Background: Preterm birth accounts for 75% of perinatal deaths and more than 50% of long-term neurological disabilities. For a singleton pregnancy, progesterone treatment is effective in prevention of preterm birth in women with an asymptomatic short cervix or a history of preterm birth. However, a large proportion of preterm births still is not c...

Long-read nanopore sequencing enables direct high-resolution breakpoint mapping on balanced carriers of reciprocal translocation. The mean sequencing depth on the translocated chromosomes to achieve accurate mapping of breakpoints ranged from 2.5-fold to 6.2-fold. To speed up determination of the breakpoints from long-read sequencing data, alignmen...

We appreciate the comments from Vyas et al. (1) Although our study demonstrated that prediction of infants' immunoprophylaxis failure (IF) is possible in early pregnancy, whether women with extremely high viral load require earlier antiviral treatment for prevention of IF remains unknown.(2) Two randomized controlled trials showed no cases of IF (0...

Human endometrium undergoes cycles of proliferation and differentiation throughout the reproductive years of women. The endometrial stem/progenitor cells contribute to this regenerative process. They lie in the basalis layer of the endometrium next to the myometrium. We hypothesized that human myometrial cells provide niche signals regulating the a...

Background: The management of the pregnancy after delivery of the first fetus during a second-trimester miscarriage or very early preterm birth has not been well defined. Objective: The objective of the study was to evaluate whether delayed interval delivery of the remaining fetus(es) in twins/triplets is associated with improved survival, when...

Introduction Balanced reciprocal translocation is one of the most common chromosomal abnormalities in humans. Carriers are usually phenotypically normal but are at an increased risk of infertility, recurrent miscarriage or having affected children. Preimplantation genetic testing for chromosomal structural rearrangement (PGT-SR) offers a way to scr...

Ultrasound examination of the endometrium is a noninvasive method to evaluate the endometrium during in vitro fertilization (IVF). A good blood supply towards the endometrium is usually considered to be an essential requirement for implantation, and assessment of endometrial blood flow may therefore predict the IVF outcomes. Doppler flow of uterine...

Objectives: To compare the proportion of women having a desired ovarian response following ovarian stimulation with gonadotrophin dosing determined based on AFC versus serum AMH level in women undergoing IVF using the GnRH antagonist protocol. Methods: This was a randomised double-blinded trial carried out in a university-affiliated assisted rep...

Introduction: Authorities publish recommendations on the hepatitis B virus (HBV) viral load threshold to initiate antiviral treatment but the timing of quantification during pregnancy is not well defined. HBV DNA levels in pregnancy women at 28-30 weeks predict the risk of immunoprophylaxis failure. This study compared and evaluated the correlatio...

Background Transvaginal oocytes retrieval is an essential step in in-vitro fertilization treatment. There are different pain relief methods, but none has been shown to be superior than the others. Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological and non-invasive pain relief method. This study aims to compare the pain leve...

Balanced reciprocal translocation carriers are usually phenotypically normal but are at an increased risk of infertility, recurrent miscarriage or having affected children. Preimplantation genetic testing on chromosomal structural rearrangement (PGT-SR) offers a way to screen against unbalanced embryos. Here, we demonstrated a new method to disting...

Introduction Robertsonian translocations are among the most common balanced structural rearrangements seen in general population with a frequency in newborn surveys of about 1 in 1000. Rob (13q14q) accounts for around 75% of all Robertsonian translocations. Because of the trivalent formations during meiosis, phenotypically normal carriers of Robert...

Aim: Increasing preimplantation genetic testing (PGT) cycles are being performed in Hong Kong. This study aims to evaluate the knowledge, attitude and ethical consideration of Chinese couples toward PGT. Methods: Couples requesting PGT between June 2013 and March 2014 were invited to complete a questionnaire. Results: Total 49 couples (49 wome...

Study question: Does glycodelin-A (GdA) induce conversion of human peripheral blood CD16-CD56bright natural killer (NK) cells to decidual NK (dNK) cells to facilitate placentation? Summary answer: GdA binds to blood CD16-CD56bright NK cells via its sialylated glycans and converts them to a dNK-like cells, which in turn regulate endothelial cell...

Purpose: To evaluate the effect of 12-month DHEA supplementation on menstrual pattern and ovarian reserve markers in women with premature ovarian insufficiency (POI) METHODS: This is a prospective observational study. Women with POI were given DHEA supplements (25 mg three times daily) for 12 months. Sonographic assessment for ovarian volume and a...

Study question: Can anti-Müllerian hormone (AMH) automated immunoassays (Elecsys® and Access) be used interchangeably as a companion diagnostic for individualisation of follitropin delta dosing? Summary answer: The Access assay gives systematically higher AMH values than the Elecsys® assay which results in over 29% of women being misclassified t...

Human varicella zoster virus (VZV) is a member of the herpes virus family and affects humans only. Information about the presence of the virus in the semen samples of men affected by chickenpox is rather limited in the literature. Here, we reported a husband was affected by VZV during in vitro fertilisation treatment of his wife treated in our cent...

Exposure to maternal diabetes during fetal growth is a risk factor for the development of type II diabetes (T2D) in later life. Discovery of the mechanisms involved in this association should provide valuable background for therapeutic treatments. Early embryogenesis involves epigenetic changes including histone modifications. The bivalent histone...

STUDY QUESTION Does the use of hCG as luteal phase support in natural cycle frozen embryo transfer (FET) increase the ongoing pregnancy rate? STUDY ANSWER The use of hCG in natural cycle FET did not improve the ongoing pregnancy rate. WHAT IS KNOWN ALREADY The use of luteal phase support in stimulated cycles has been associated with higher live-b...

STUDY QUESTION How do the three new anti-Müllerian hormone (AMH) assay methods, manufactured by Beckman Coulter, Roche and Ansh Labs compare with each other and with the Gen II assay? SUMMARY ANSWER The three new AMH assays are well correlated among themselves and with the Gen II assay, although differences in calibration do exist. WHAT IS KNOWN...

Background Miscarriage is a common complication of pregnancy occurring in 15–20 % of all clinically recognized pregnancies. Currently, there is still no good scientific evidence to support the routine use of progestogens for the treatment of threatened miscarriage because the existing studies were not large enough to show a significant difference a...