Gestational hormone trajectories and early pregnancy failure: a reassessment

BaP/BPDE suppresses human trophoblast cell migration/invasion and induces unexplained miscarriage by up-regulating a novel lnc-HZ11 in extracellular vesicles: An intercellular study

Extracellular vesicles (EVs) mediate the intercellular crosstalk by transferring functional cargoes. Recently, we have discovered that BaP/BPDE exposure suppresses trophoblast cell migration/invasion and induces miscarriage, which are also regulate by lncRNAs at intracelluar levels. However, the EVs-mediated intercellular regulatory mechanisms are completely unexplored. Specifically, whether EVs might transfer BPDE-induced toxic lncRNA to fresh recipient trophoblast cells and suppress their migration/invasion to further induce miscarriage is completely unknown. In this study, we find that BPDE exposure up-regulates a novel lnc-HZ11, which suppresses EGR1/NF-κB/CXCL12 pathway and migration/invasion of trophoblast cells. Intercellular studies show that EV-HZ11 (lnc-HZ11 in EVs), which is highly expressed in BPDE-exposed donor cells, suppresses EGR1/NF-κB/CXCL12 pathway and migration/invasion in recipient cells by transferring lnc-HZ11 through EVs. Analysis of villous tissues collected from UM (unexplained miscarriage) patients and HC (healthy control) group shows that the levels of BPDE-DNA adducts, lnc-HZ11 or EV-lnc-HZ11, and EGR1/NF-κB/CXCL12 pathway are all associated with miscarriage. Mouse assays show that BaP exposure up-regulates the levels of lnc-Hz11 or EV-Hz11, suppresses Egr1/Nf-κb/Cxcl12 pathway, and eventually induces miscarriage. Knockdown of lnc-Hz11 by injecting EV-AS-Hz11 could effectively alleviate miscarriage in BaP-exposed mice. Furthermore, EV-HZ11 in serum samples could well predict the risk of miscarriage. Collectively, this study not only discovers EVs-HZ11-mediated intercellular mechanisms that BaP/BPDE suppresses trophoblast cell migration/invasion and induces miscarriage but also provides new approach for treatment against unexplained miscarriage through EV-HZ11.

The Relationship Between the Average Decreased Times of Estradiol and Early Miscarriage: An Observational Study

Decreased estradiol (E2) levels are associated with early miscarriage (EM), but the relationship between decreased times of E2 and EM has not been reported. We aimed to investigate the relationship between the average decreased times of E2 (ADTE) and EM. Women with a history of miscarriage were retrospectively recruited from the Reproductive Center of Lanzhou University Second Hospital (Lanzhou, China) between September 2019 and February 2022. Based on pregnancy outcome, they were divided into ongoing pregnancy group (n = 359) and EM group (n = 104). In addition, subgroup analyses were performed for the number of previous miscarriages and whether E2 levels decreased continuously. The exposure and outcome variables were ADTE and miscarriage before 12 weeks of gestation, respectively. Totally, 1171 patients were recruited and 463 patients were finally analyzed. ADTE was associated with EM (odds ratio [OR] = 1.346, 95% confidence interval [CI]1.154-1.571, P < 0.001). When ADTE ≥ 2.5, the EM risk increased 1.17-fold compared to patients with 0-1.249 times (OR = 2.170, 95% CI 1.144-4.117, P = 0.018). Moreover, a threshold effect existed in the ADTE and the risk of EM with a value of 4.9 times. When exceeding 4.9 times, the EM risk increased 4.713-fold for each increased unit (OR = 5.713, 95% CI 1.255-23.170, P = 0.024). Subgroup analysis showed that ADTE had a greater effect on the occurrence of EM in women with a history of 1-2 miscarriages than in women with 3 miscarriages. Decreased E2 was a risk factor for EM regardless of whether it dropped continuously or not. In conclusion, our study identifies a potential link between ADTE and early miscarriage risk in women with prior miscarriages, yet cautious interpretation is necessary due to inherent design limitations. Further research with prospective designs and large population samples is essential to validate ADTE's utility as a predictive indicator for early miscarriage in clinical settings.

Exploring Progesterone Deficiency in First-Trimester Miscarriage and the Impact of Hormone Therapy on Foetal Development: A Scoping Review

Background and Objectives: Progesterone deficiency during pregnancy may lead to various complications, including first-trimester miscarriage, which is the most common pregnancy complication. However, progesterone therapy may play a role in pregnancy maintenance and foetal development. The aim of this scoping review is to present evidence on the link between progesterone deficiency and first-trimester miscarriage among pregnant women and assess the impact of progesterone therapy on foetal development. Methods: A comprehensive global systematic search of mainly primary research studies was conducted using several databases. Peer-reviewed studies published between 2010 and 2023 were included. The scoping review was conducted using the framework outlined by the Joanna Briggs Institute (JBI) and reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Extension for Scoping Reviews (PRISMA-ScR) statement. Results: Twenty-three articles (which included 35,862 participants) were included in the analysis. Most studies were conducted in mid- to high-income countries. All 23 articles reported a significant positive relationship between progesterone deficiency and first-trimester miscarriage. Furthermore, the majority of studies reported a higher risk of miscarriage when lower levels of progesterone are combined with other declined hormones. While most studies reported that progesterone therapy may reduce the rate of first-trimester miscarriage among pregnant women, no evidence of health-related harm to offspring development was reported. Conclusions: The findings from this systematic-scoping review indicate possible benefits of progesterone replacement therapy in maintaining a healthy pregnancy and foetal development. Rigorous studies that include large sample sizes and systematic reviews are required to confirm these findings further.

A Novel Approach to Predicting Early Pregnancy Outcomes Dynamically in a Prospective Cohort Using Repeated Ultrasound and Serum Biomarkers

This study aimed to develop a dynamic model for predicting outcome during the first trimester of pregnancy using baseline demographic data and serially collected blood samples and transvaginal sonographies. A prospective cohort of 203 unselected women with an assumed healthy pregnancy of < 8 weeks' gestation was followed fortnightly from 4-14 weeks' gestation until either miscarriage or confirmed first trimester viability. The main outcome was development of a model to predict outcome from gestational age-dependent hazard ratios using both baseline and updated serial data from each visit. Secondary outcomes were descriptions of risk factors for miscarriage. The results showed that 18% of the women experienced miscarriages. A fetal heart rate detected before 8 weeks' gestation indicated a 90% (95% CI 85-95%) chance of subsequent delivery. Maternal age (≥ 35 years), insufficient crown-rump-length (CRL) and mean gestational sac diameter (MSD) development, and presence of bleeding increased the risk of miscarriage. Serum biomarkers, including hCG, progesterone, and estradiol, were found to impact the risk of miscarriage with estradiol as the most important. The best model to predict miscarriage was a combination of maternal age, vaginal bleeding, CRL, and hCG. The second-best model was the sonography-absent model of maternal age, bleeding, hCG, and estradiol. This study suggests that combining maternal age, and evolving data from hCG, estradiol, CRL, and bleeding could be used to predict fetal outcome during the first trimester of pregnancy.Trial registration ClinicalTrials.gov identifier: NCT02761772.

The pathophysiological role of estrogens in the initial stages of pregnancy: molecular mechanisms and clinical implications for pregnancy outcome from the periconceptional period to end of the first trimester

BACKGROUND

Estrogens regulate disparate female physiological processes, thus ensuring reproduction. Altered estrogen levels and signaling have been associated with increased risks of pregnancy failure and complications, including hypertensive disorders and low birthweight babies. However, the role of estrogens in the periconceptional period and early pregnancy is still understudied.

OBJECTIVE AND RATIONALE

This review aims to summarize the current evidence on the role of maternal estrogens during the periconceptional period and the first trimester of pregnancies conceived naturally and following ART. Detailed molecular mechanisms and related clinical impacts are extensively described.

SEARCH METHODS

Data for this narrative review were independently identified by seven researchers on Pubmed and Embase databases. The following keywords were selected: 'estrogens' OR 'estrogen level(s)' OR 'serum estradiol' OR 'estradiol/estrogen concentration', AND 'early pregnancy' OR 'first trimester of pregnancy' OR 'preconceptional period' OR 'ART' OR 'In Vitro Fertilization (IVF)' OR 'Embryo Transfer' OR 'Frozen Embryo Transfer' OR 'oocyte donation' OR 'egg donation' OR 'miscarriage' OR 'pregnancy outcome' OR 'endometrium'.

OUTCOMES

During the periconceptional period (defined here as the critical time window starting 1 month before conception), estrogens play a crucial role in endometrial receptivity, through the activation of paracrine/autocrine signaling. A derailed estrogenic milieu within this period seems to be detrimental both in natural and ART-conceived pregnancies. Low estrogen levels are associated with non-conception cycles in natural pregnancies. On the other hand, excessive supraphysiologic estrogen concentrations at time of the LH peak correlate with lower live birth rates and higher risks of pregnancy complications. In early pregnancy, estrogen plays a massive role in placentation mainly by modulating angiogenic factor expression-and in the development of an immune-tolerant uterine micro-environment by remodeling the function of uterine natural killer and T-helper cells. Lower estrogen levels are thought to trigger abnormal placentation in naturally conceived pregnancies, whereas an estrogen excess seems to worsen pregnancy development and outcomes.

WIDER IMPLICATIONS

Most current evidence available endorses a relation between periconceptional and first trimester estrogen levels and pregnancy outcomes, further depicting an optimal concentration range to optimize pregnancy success. However, how estrogens co-operate with other factors in order to maintain a fine balance between local tolerance towards the developing fetus and immune responses to pathogens remains elusive. Further studies are highly warranted, also aiming to identify the determinants of estrogen response and biomarkers for personalized estrogen administration regimens in ART.

A Novel System for the Detection of Spontaneous Abortion-Causing Aneuploidy and Its Erroneous Chromosome Origins through the Combination of Low-Pass Copy Number Variation Sequencing and NGS-Based STR Tests

During the period of 2018-2020, we first combined reported low-pass whole genome sequencing and NGS-based STR tests for miscarriage samples analysis. Compared with G-banding karyotyping, the system increased the detection rate of chromosomal abnormalities in miscarriage samples to 56.4% in 500 unexplained recurrent spontaneous abortions. In this study, a total of 386 STR loci were developed on twenty-two autosomes and two sex chromosomes (X and Y chromosomes), which can help to distinguish triploidy, uniparental diploidy and maternal cell contamination and can trace the parental origin of erroneous chromosomes. It is not possible to accomplish this with existing methods of detection in miscarriage samples. Among the tested aneuploid errors, the most frequently detected error was trisomy (33.4% in total and 59.9% in the error chromosome group). In the trisomy samples, 94.7% extra chromosomes were of maternal origin and 5.31% were of paternal origin. This novel system improves the genetic analysis method of miscarriage samples and provides more reference information for clinical pregnancy guidance.

Performance of single serum progesterone in the evaluation of symptomatic first-trimester pregnant patients: a systematic review and meta-analysis

OBJECTIVES

Pain and bleeding complicate 30% of pregnancies, raising concerns for viability. The objective is to evaluate the diagnostic characteristics of a single serum progesterone level in assessing pregnancy viability among symptomatic patients.

METHODS

We conducted a predefined literature search in MEDLINE, Embase (OVID), CINAHL and Cochrane databases for studies that enrolled patients in first trimester with miscarriage symptoms, measured progesterone and reported pregnancy viability, from inception to July 2020. We extracted data for 2 × 2 tables, progesterone threshold levels and viability. We obtained summary estimates of sensitivity, specificity, Diagnostic Odds Ratio (DOR), and predictive values at given prevalence rates.

RESULTS

We identified 54 publications. There was a total of 15,878 patients enrolled, of whom 7864 patients (49.5%) were confirmed to have a viable pregnancy and 8014 patients (50.5%) were confirmed to have a non-viable pregnancy. The cut-off value of progesterone ranged from 3.2 to 25 ng/mL (20.034-79.5 nmol/L). We evaluated the performance of the following progesterone cut-off categories: < 6.3, 6.3-12.6, 12.7-19.9, and 20-25 ng/mL. To detect non-viable pregnancy, progesterone with cut-off < 6.3 ng/mL had sensitivity 73.1%, specificity 99.2% and DOR 322.0 (PPV 0.91, 0.97 and 0.99 at prevalences 0.1, 0.25, 0.5, respectively, indicating higher likelihood of non-viable pregnancy), and cut-off category 20-25 ng/mL had sensitivity 91.3%, specificity 75% and DOR 31.4 (NPV 0.99, 0.96 and 0.89 at the prevalences above indicating higher likelihood of viable pregnancy).

CONCLUSION

A single progesterone level provides a clinically useful prognostic information on pregnancy viability. More than nine out of ten patients with a level < 6.3 ng/mL (< 20.034 nmol/L) will be diagnosed with a non-viable pregnancy, and more than 90% of patients with a level ≥ 20-25 ng/mL (63.6-79.5 nmol/L) will have a viable pregnancy confirmed.

Case Report: TNF-Alpha Inhibitors to Rescue Pregnancy in Women With Potential Pregnancy Loss: A Report of Ten Cases

Miscarriage poses a significant threat to pregnant women globally. Recurrent miscarriages or potential poor embryonic development indicated by early drops in serum human chorionic gonadotrophin (hCG) are even more catastrophic for pregnant women. However, these patients receive either individualized medical intervention supported by limited evidence or no treatment at all. In this study, we report ten patients who shared at least one episode of an early decline of hCG in the first trimester and were treated with compassionate use of tumor necrosis factor-alpha inhibitor (TNFi). They were then followed up regularly with caution. Their hCG trajectory all resumed a normal pattern within one week and the obstetric outcomes were promising. No adverse fetal, neonatal, or maternal health issues have been observed. This case series supports current safety evidence of TNFi and provides new insight into its use in pregnancy when the embryo is in danger. Further well-designed clinical trials should be carried out to consolidate the evidence.

Proteome-defined changes in cellular pathways for decidua and trophoblast tissues associated with location and viability of early-stage pregnancy

BACKGROUND

In early pregnancy, differentiating between a normal intrauterine pregnancy (IUP) and abnormal gestations including early pregnancy loss (EPL) or ectopic pregnancy (EP) is a major clinical challenge when ultrasound is not yet diagnostic. Clinical treatments for these outcomes are drastically different making early, accurate diagnosis imperative. Hence, a greater understanding of the biological mechanisms involved in these early pregnancy complications could lead to new molecular diagnostics.

METHODS

Trophoblast and endometrial tissue was collected from consenting women having an IUP (n = 4), EPL (n = 4), or EP (n = 2). Samples were analyzed by LC-MS/MS followed by a label-free proteomics analysis in an exploratory study. For each tissue type, pairwise comparisons of different pregnancy outcomes (EPL vs. IUP and EP vs. IUP) were performed, and protein changes having a fold change ≥ 3 and a Student's t-test p-value ≤ 0.05 were defined as significant. Pathway and network classification tools were used to group significantly changing proteins based on their functional similarities.

RESULTS

A total of 4792 and 4757 proteins were identified in decidua and trophoblast proteomes. For decidua, 125 protein levels (2.6% of the proteome) were significantly different between EP and IUP, whereas EPL and IUP decidua were more similar with only 68 (1.4%) differences. For trophoblasts, there were 66 (1.4%) differences between EPL and IUP. However, the largest group of 344 differences (7.2%) was observed between EP and IUP trophoblasts. In both tissues, proteins associated with ECM remodeling, cell adhesion and metabolic pathways showed decreases in EP specimens compared with IUP and EPL. In trophoblasts, EP showed elevation of inflammatory and immune response pathways.

CONCLUSIONS

Overall, differences between an EP and IUP are greater than the changes observed when comparing ongoing IUP and nonviable intrauterine pregnancies (EPL) in both decidua and trophoblast proteomes. Furthermore, differences between EP and IUP were much higher in the trophoblast than in the decidua. This observation is true for the total number of protein changes as well as the extent of changes in upstream regulators and related pathways. This suggests that biomarkers and mechanisms of trophoblast function may be the best predictors of early pregnancy location and viability.

Sexual dimorphism in placental development and its contribution to health and diseases

According to the Developmental Origin of Health and Disease (DOHaD), intrauterine exposure to adverse environments can affect fetus and birth outcomes and lead to long-term disease susceptibility. Evidence has shown that neonatal outcomes and the timing and severity of adult diseases are sexually dimorphic. As the link between mother and fetus, the placenta is an essential regulator of fetal development programming. It is found that the physiological development trajectory of the placenta has sexual dimorphism. Furthermore, under pathological conditions, the placental function undergoes sex-specific adaptation to ensure fetal survival. Therefore, the placenta may be an important mediator of sexual dimorphism in neonatal outcomes and adult disease susceptibility. Few systematic reviews have been conducted on sexual dimorphism in placental development and its underlying mechanisms. In this review, sex chromosomes and sex hormones, as the main reasons for sexual differentiation of the placenta, will be discussed. Besides, in the etiology of fetal-originated adult diseases, overexposure to glucocorticoids is closely related to adverse neonatal outcomes and long-term disease susceptibility. Studies have found that prenatal glucocorticoid overexposure leads to sexually dimorphic expression of placental glucocorticoid receptor isoforms, resulting in different sensitivity of the placenta to glucocorticoids, and may further affect fetal development. The present review examines what is currently known about sex differences in placental development and the underlying regulatory mechanisms of this sex bias. This review highlights the importance of placental contributions to the origins of sexual dimorphism in health and diseases. It may help develop personalized diagnosis and treatment strategies for fetal development in pathological pregnancies.

Changes in the level of fetoplacental complex hormones in pregnant women with miscarriage

The purpose of the study was TO analyze the fetoplacental complex hormone levels and changes in their dynamics in pregnant women with miscarriage and the impact of these features on the subsequent course of pregnancy. Hormone levels were determined at different stages of gestation in 50 healthy women with a physiological course of pregnancy (control group) and 50 pregnant women with a history of miscarriage (main group). The women of the main group had a significantly slower rate of increase in hormones and a lag in quantitative indicators than the control group. The estradiol level indicators were 4.1 times (76.0%) and 2.89 times (65.5%) lower in women with miscarriage in the embryonic and late fetal period, respectively, compared to healthy women. Indicators of the level of placental lactogen and chorionic gonadotropin in the embryonic period in women with miscarriage were lower by 39.1% and 50.9%, respectively, compared to healthy women. In the late fetal period, the level of these hormones was lower by 72.9% and 35.4%, respectively. In the embryonic and late fetal periods, progesterone levels were lower by 67.4% and 68.4%, respectively, compared to the control group. The data obtained are evidence of a pronounced hormonal abnormality of the placenta, and hence a marker of fetoplacental dysfunction, which on the background of miscarriage develops at the early stages and continues to progress with the course of pregnancy.

Initial data on the safety of metopimazine during pregnancy and the risk of major birth defects and pregnancy loss - An observational study using the EFEMERIS database

INTRODUCTION

Metopimazine is an anti-emetic drug used to treat nausea and vomiting of pregnancy. However, no animal or clinical data are available regarding its safety in pregnant women. The aim of this study was, therefore, to assess the risk of birth defects and pregnancy loss associated with the use of metopimazine during pregnancy in a population-based cohort study.

METHODS

The study focused on the EFEMERIS database including the prescription and dispensation of drugs for pregnant women in Haute-Garonne, France, between July 2004 and December 2017. This was an observational, retrospective, comparative study. Pregnancy loss and major birth defects were compared between women exposed to metopimazine during pregnancy and those with no exposure using multivariate logistic regression and Cox proportional risk models.

RESULTS

Among 135,574 pregnant women, 11,402 (8.2%) were exposed to metopimazine during pregnancy, mostly in the first trimester (more than 70% of women). No association was found between major birth defects and exposure to metopimazine in the first trimester of pregnancy (OR_a=[95% CI]=1.06 [0.92-1.23]). Pregnancy loss was negatively associated with metopimazine use during pregnancy (HR_a [95% CI]=0.80 [0.72-0.88]), taking into account major potential confounders. Comparable rates were recorded between women exposed to metopimazine and those unexposed to the drug in terms of prematurity (6.7% vs. 6.4%), low birth weight (6.2% vs. 6.2%) and small for gestational age (1.2% vs. 1.4%).

CONCLUSION

This study illustrates the wide use of metopimazine during pregnancy in France although no studies on efficacy or safety in pregnant women are available. The results of this study do not indicate any teratogenic effect or an increased risk of pregnancy loss of metopimazine.

Oestradiol promotes the intrahepatic bile duct development of C57BL/6CrSlc mice during embryonic period via Notch signalling pathway

Oestradiol (E2) is a critical factor for multiple systems' development during the embryonic period. Here, we aimed to investigate the effects of oestradiol on intrahepatic bile duct development, which may allow a better understanding of congenital bile duct dysplasia. DLK⁺ hepatoblasts were extracted from the C57BL/6CrSlc foetal mice and randomly divided into control group, oestradiol groups (1, 10, 100 nM) and oestradiol (10 nM) + DAPT (inhibitor of Notch signalling; 40 µM) group for in vitro experiments. For in vivo analysis, pregnant mice were divided into control group, oestradiol (intraperitoneal injection of 0.6 mg/kg/day) ± DAPT (subcutaneous injection of 10 mg/kg/day) groups and tamoxifen (gavage administration of 0.4 mg/kg/day) group. The results showed that oestradiol promoted hepatoblast differentiation into cholangiocytes and intrahepatic bile duct development during the embryonic period. Tamoxifen, an antioestrogenic drug, inhibited the above processes. Moreover, oestradiol promoted the expression of Notch signalling pathway‐associated proteins and genes both in vitro and in vivo. Notably, DAPT addition inhibited the oestradiol‐mediated effects. In conclusion, oestradiol can promote hepatoblast differentiation into cholangiocytes and intrahepatic bile duct development of C57BL/6CrSlc mice during embryonic period via the Notch signalling pathway.

Risk of Pregnancy Termination and Congenital Anomalies After Domperidone Exposure: A Study in the EFEMERIS Database

INTRODUCTION

Domperidone is widely used during pregnancy, although the risks associated with pregnant women have not been adequately evaluated.

OBJECTIVE

The objective of this study was to compare the rate of pregnancy outcomes and congenital anomalies between pregnant women exposed and unexposed to domperidone during pregnancy.

METHODS

We conducted a retrospective cohort study comparing pregnant women exposed and unexposed to domperidone during pregnancy. We used the EFEMERIS database containing the prescriptions and dispensing of drugs to pregnant women in Haute-Garonne, who had a pregnancy outcome between July 2004 and December 2017. We compared pregnant women who were exposed to domperidone at least once during pregnancy to unexposed pregnant women. Logistic regression and Cox proportional risk models were applied.

RESULTS

Overall, 13,964 pregnancies (10.3% of pregnancies) were given domperidone. A reduction in the number of pregnant women exposed to domperidone (2004: 17.1% to 2017: 1.2%) was noted. More than 75% of pregnancies were exposed to domperidone in the first trimester of pregnancy. The rate of natural pregnancy termination in pregnant women exposed to domperidone was lower than that in unexposed pregnant women (adjusted hazard ratio = 0.78 [0.71-0.87]). The malformation rate in fetuses/newborns exposed in utero (first trimester) to domperidone is comparable to that of unexposed fetuses/newborns (adjusted odd ratio = 0.89 [0.77-1.03]).

CONCLUSIONS

This is the first comparative study to enrol a large number of pregnant women exposed to domperidone. Data regarding the malformation rate following exposure to domperidone during the first trimester of pregnancy are reassuring. Women exposed to domperidone during pregnancy have a decreased risk for natural pregnancy termination, probably owing to an indication bias.

GnRHa for trigger and luteal phase support in natural cycle frozen embryo transfer - A proof of concept study

We aimed to explore whether ovulation induced by a GnRH analogue (GnRHa), followed by daily GnRHa luteal support provides an efficient platform for natural cycle frozen embryo transfer (NC-FET). In this cohort study, included were normo-ovulatory women who underwent NC-FET cycles, under the age of 40, with an antral follicle count > eight. Ovulation was triggered with triptorelin (0.2 mg Decapeptyl; Ferring), and luteal support was initiated two days later, using a Nafarelin inhaler (Synarel, Pfizer), 200 μg twice daily. Main outcome measures were luteal estradiol and progesterone levels (three to five days following ovulation), implantation rate, ongoing pregnancy rate, early pregnancy loss rate, and live birth rate. Fifty-one patients treated between 2017 and 2018 were included. Mid luteal progesterone levels among study patients, were non-significantly different between patients who achieved pregnancy and those who did not, but differed significantly on day 14 following ovulation (86.0 ± 31.3 vs. 9.8 ± 9.5 nmol/L, respectively, p < 0.001). Twenty-three patients achieved a clinical pregnancy (45.1 %); interestingly, there were no chemical pregnancies. Three pregnancies ended in an early abortion at 6-7 weeks gestation, and 20 pregnancies continued as ongoing pregnancies (39.2 %). One patient had a late abortion at 16 weeks gestation, and 14 had a live birth. In conclusion, in this proof of concept study, inducing ovulation with a bolus of GnRHa in NC-FET, followed by repeated daily GnRHa administration, resulted in satisfactory luteal phase steroid levels and high ongoing pregnancy and live birth rates.

Pregnancy duration and endometrial cancer risk: nationwide cohort study

OBJECTIVE

To explore the association between pregnancy duration and risk of endometrial cancer.

DESIGN

Nationwide register based cohort study.

SETTING

Denmark.

PARTICIPANTS

All Danish women born from 1935 to 2002.

MAIN OUTCOME MEASURES

Relative risk (incidence rate ratio) of endometrial cancer by pregnancy number, type, and duration, estimated using log-linear Poisson regression.

RESULTS

Among 2 311 332 Danish women with 3 947 650 pregnancies, 6743 women developed endometrial cancer during 57 347 622 person years of follow-up. After adjustment for age, period, and socioeconomic factors, a first pregnancy was associated with a noticeably reduced risk of endometrial cancer, whether it ended in induced abortion (adjusted relative risk 0.53 (95% confidence interval 0.45 to 0.64) or childbirth (0.66, 0.61 to 0.72). Each subsequent pregnancy was associated with an additional reduction in risk, whether it ended in induced abortion (0.81, 0.77 to 0.86) or childbirth (0.86, 0.84 to 0.89). Duration of pregnancy, age at pregnancy, spontaneous abortions, obesity, maternal birth cohort, fecundity, and socioeconomic factors did not modify the results.

CONCLUSIONS

The risk of endometrial cancer is reduced regardless of whether a pregnancy ends shortly after conception or at 40 weeks of gestation. This reduction in risk could be explained by a biological process occurring within the first weeks of pregnancy, as pregnancies ending in induced abortions were associated with similar reductions in risk as pregnancies ending in childbirth.