Miscarriage is a common, complex trait affecting ~15% of clinically confirmed pregnancies. Here we present the results of large-scale genetic association analyses with 69,054 cases from five different ancestries for sporadic miscarriage, 750 cases of European ancestry for multiple (≥3) consecutive miscarriage, and up to 359,469 female controls. We identify one genome-wide significant association (rs146350366, minor allele frequency (MAF) 1.2%, P = 3.2 × 10−8, odds ratio (OR) = 1.4) for sporadic miscarriage in our European ancestry meta-analysis and three genome-wide significant associations for multiple consecutive miscarriage (rs7859844, MAF = 6.4%, P = 1.3 × 10−8, OR = 1.7; rs143445068, MAF = 0.8%, P = 5.2 × 10−9, OR = 3.4; rs183453668, MAF = 0.5%, P = 2.8 × 10−8, OR = 3.8). We further investigate the genetic architecture of miscarriage with biobank-scale Mendelian randomization, heritability, and genetic correlation analyses. Our results show that miscarriage etiopathogenesis is partly driven by genetic variation potentially related to placental biology, and illustrate the utility of large-scale biobank data for understanding this pregnancy complication.

SummaryMaternal systemic inflammation is a feature of pre-eclampsia, a condition in pregnancy characterized by hypertension and proteinuria. Pre-eclampsia is caused by the placenta; many placental factors contribute to the syndrome's progression, and proinflammatory cytokines have been identified previously as one such mediator. The interleukin (IL)-1 family of cytokines are key regulators of the inflammatory network, and two naturally occurring regulatory molecules for IL-1 family cytokines, IL-1RA and sST2, have been found previously to be elevated in maternal blood from women with preeclampsia. Here we investigate more recently identified IL-1 family cytokines and regulatory molecules, IL-1RAcP, IL-37, IL-18BP, IL-36a/b/g/ Ra and IL-38 in pre-eclampsia. Pregnant women have more circulating IL-18BP and IL-36Ra than non-pregnant women, and sIL-1RAcP is elevated from women with pre-eclampsia compared to normal pregnancies. The placenta expresses all the molecules, and IL-37 and IL-18BP are upregulated significantly in pre-eclampsia placentas compared to those from normal pregnancies. Together, these changes contribute to the required inhibition of maternal systemic cytotoxic immunity in normal pregnancy; however, in pre-eclampsia the same profile is not seen. Interestingly, the increased circulating levels of sIL-1RAcP and increased placental IL-18BP and IL-37, the latter of which we show to be induced by hypoxic damage to the placenta, are all factors which are anti-inflammatory. While the placenta is often held responsible for the damage and clinical symptoms of preeclampsia by the research community, here we show that the pre-eclampsia placenta is also trying to prevent inflammatory damage to the mother.

Long-term GnRH agonist therapy before in vitro fertilisation (IVF) for improving fertility outcomes in women with endometriosis.

Extracellular vesicles are highly abundant in seminal fluids and have a known role enhancing sperm function. Clinical pregnancy rates after IVF treatment are improved after female exposure to seminal fluid. Seminal fluid extracellular vesicles (SF-EVs) are candidate enhancers, however, whether SF-EVs interact with cells from the endometrium and modulate the implantation processes is unknown. Here, we investigated whether SF-EVs interact with endometrial stromal cells (ESCs) and enhance decidualisation, a requisite for implantation. SF-EVs, isolated from human seminal fluid (n = 11) by ultracentrifugation, were characterised by nanoparticle tracking analysis and Western blotting, and purified using size exclusion chromatography. Non-decidualised and decidualised primary ESCs (n = 5) were then treated with SF-EVs. Binding of bio-maleimide-labelled SF-EVs was detected by flow cytometry and fluorescence microscopy. Prolactin and IGFBP-1 protein levels in culture media were also analysed after single and multiple SF-EV exposure. SF-EVs size ranged from 50 to 300 nm, and they expressed exosomal markers (ALIX, SYNTENIN-1, CD9 and CD81). SF-EVs bound to non-decidualised and decidualised ESCs at similar levels. ESCs prolactin secretion was increased after single (p = 0.0044) and multiple (p = 0.0021) SF-EV exposure. No differences were found in IGFBP-1 protein levels. In conclusion, SF-EVs enhance in vitro ESC decidualisation and increase secretion of prolactin, an essential hormone in implantation. This elucidates a novel role of SF-EVs on endometrial receptivity. Abbreviations: ECACC: European Collection of Authenticated Cell Cultures; ESCs: endometrial stromal cells; EVs: extracellular vesicles; FCS: foetal calf serum; HRP: horse-radish peroxidase; IFNγ: interferon-gamma; IGF: insulin-like growth factor; IGFBP-1: insulin-like growth factor binding protein 1; IVF: in vitro fertilisation; MVB: multivesicular bodies; NTA: nanoparticle tracking analysis; PRLR−/−: homozygous prolactin receptor knockout; RT: room temperature; SF-EVs: seminal fluid extracellular vesicles; STR: short tandem repeat; TGFβ: transforming growth factor β; uNK: uterine natural killer

When trying to conceive 1% of couples have recurrent miscarriages, defined as three or more consecutive pregnancy losses. This is not accounted for by the known incidence of chromosomal aneuploidy in miscarriage, and it has been suggested that there is an immunological aetiology. The endometrial mucosa is populated by a variety of immune cells which in addition to providing host pathogen immunity must facilitate pregnancy. Here we characterise the endometrial CD8-T cell population during the embryonic window of implantation and find that the majority of cells are tissue resident memory T cells with high levels of CD69 and CD103 expression, proteins that prevent cells egress. We demonstrate that unexplained recurrent miscarriage is associated with significantly decreased expression of the T-cell co-receptor CD8 and tissue residency marker CD69. These cells differ from those found in control women, with less expression of CD127 indicating a lack of homeostatic cell control through IL-7 signalling. Nevertheless this population is resident in the endometrium of women who have RM, more than three months after the last miscarriage, indicating that the memory CD8-T cell population is altered in RM patients. This is the first evidence of a differing pre-pregnancy phenotype in endometrial immune cells in RM.

Background Obesity is observationally associated with altered risk of many female reproductive conditions. These include polycystic ovary syndrome (PCOS), abnormal uterine bleeding, endometriosis, infertility, and pregnancy-related disorders. However, the roles and mechanisms of obesity in the aetiology of reproductive disorders remain unclear. Thus, we aimed to estimate observational and genetically predicted causal associations between obesity, metabolic hormones, and female reproductive disorders. Methods and findings Logistic regression, generalised additive models, and Mendelian randomisation (MR) (2-sample, non-linear, and multivariable) were applied to obesity and reproductive disease data on up to 257,193 women of European ancestry in UK Biobank and publicly available genome-wide association studies (GWASs). Body mass index (BMI), waist-to-hip ratio (WHR), and WHR adjusted for BMI were observationally (odds ratios [ORs] = 1.02–1.87 per 1-SD increase in obesity trait) and genetically (ORs = 1.06–2.09) associated with uterine fibroids (UF), PCOS, heavy menstrual bleeding (HMB), and pre-eclampsia. Genetically predicted visceral adipose tissue (VAT) mass was associated with the development of HMB (OR [95% CI] per 1-kg increase in predicted VAT mass = 1.32 [1.06–1.64], P = 0.0130), PCOS (OR [95% CI] = 1.15 [1.08–1.23], P = 3.24 × 10−05), and pre-eclampsia (OR [95% CI] = 3.08 [1.98–4.79], P = 6.65 × 10−07). Increased waist circumference posed a higher genetic risk (ORs = 1.16–1.93) for the development of these disorders and UF than did increased hip circumference (ORs = 1.06–1.10). Leptin, fasting insulin, and insulin resistance each mediated between 20% and 50% of the total genetically predicted association of obesity with pre-eclampsia. Reproductive conditions clustered based on shared genetic components of their aetiological relationships with obesity. This study was limited in power by the low prevalence of female reproductive conditions among women in the UK Biobank, with little information on pre-diagnostic anthropometric traits, and by the susceptibility of MR estimates to genetic pleiotropy. Conclusions We found that common indices of overall and central obesity were associated with increased risks of reproductive disorders to heterogenous extents in a systematic, large-scale genetics-based analysis of the aetiological relationships between obesity and female reproductive conditions. Our results suggest the utility of exploring the mechanisms mediating the causal associations of overweight and obesity with gynaecological health to identify targets for disease prevention and treatment.

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STUDY QUESTION Does the method of fertilisation improve reproductive outcomes in poor ovarian response (POR) cycles when compared to all other ovarian response categories in the absence of male factor subfertility? SUMMARY ANSWER ICSI does not confer any benefit in improving the clinical pregnancy or live birth (LB) outcome in autologous ovarian response cycles in the absence of male factor subfertility when compared to IVF. WHAT IS KNOWN ALREADY ICSI is associated with an improved outcome when compared to IVF in patients with severe male factor subfertility. STUDY DESIGN, SIZE, DURATION A retrospective study involving 1 376 454 ART cycles, of which 569 605 (41.4%) cycles fulfilled the inclusion and exclusion criteria for all autologous ovarian response categories: 272 433 (47.8%) IVF cycles and 297 172 (52.2%) ICSI cycles. Of these, the POR cohort represented 62 641 stimulated fresh cycles (11.0%): 33 436 (53.4%) IVF cycles and 29 205 (46.6%) ICSI cycles. PARTICIPANTS/MATERIALS, SETTING, METHOD All cycles recorded on the anonymised Human Fertilisation and Embryology Authority (HFEA) registry database between 1991 and 2016 were analysed. All fresh cycles with normal sperm parameters, performed after 1998 were included: frozen cycles, donor oocyte and sperm usage, intrauterine insemination cycles, preimplantation genetic testing (PGT) for aneuploidies (PGT-A), PGT for monogenic/single gene defects (PGT-M), PGT for chromosomal structural arrangements (PGT-SR) cycles, where the reason for stimulation was for storage and unstimulated cycles were excluded. MAIN RESULTS AND THE ROLE OF CHANCE ICSI did not confer any benefit in improving the LB outcome when compared to conventional IVF per treatment cycle (PTC), when adjusted for female age, number of previous ART treatment cycles, number of previous live births through ART, oocyte yield, stage of transfer, method of fertilisation and number of embryos transferred in the POR cohort (adjusted odds ratio [a OR] 1.03, 99.5% confidence interval [CI] 0.96–1.11, P = 0.261) and all autologous ovarian response categories (aOR 1.00, 99.5% CI 0.98–1.02, P = 0.900). The mean fertilisation rate was statistically lower for IVF treatment cycles (64.7%) when compared to ICSI treatment cycles (67.2%) in the POR cohort (mean difference −2.5%, 99.5% CI −3.3 to −1.6, P < 0.001). The failed fertilisation rate was marginally higher in IVF treatment cycles (17.3%, 95% binomial exact 16.9 to 17.7%) when compared to ICSI treatment cycles (17.0%, 95% binomial exact 16.6 to 17.4%); however, this did not reach statistical significance (P = 0.199). The results followed a similar trend when analysed for all autologous ovarian response categories with a higher rate of failed fertilisation in IVF treatment cycles (4.8%, 95% binomial exact 4.7 to 4.9%) when compared to ICSI treatment cycles (3.2%, 95% binomial exact 3.1 to 3.3%) (P < 0.001). LIMITATIONS, REASONS FOR CAUTION The quality of data is reliant on the reporting system. Furthermore, success rates through ART have improved since 1991, with an increased number of blastocyst-stage embryo transfers. The inability to link the treatment cycle to the individual patient meant that we were unable to calculate the cumulative LB outcome per patient. WIDER IMPLICATIONS OF THE FINDINGS This is the largest study to date which evaluates the impact of method of fertilisation in the POR patient and compares this to all autologous ovarian response categories. The results demonstrate that ICSI does not confer any benefit in improving reproductive outcomes in the absence of male factor subfertility, with no improvement seen in the clinical pregnancy or LB outcomes following a fresh treatment cycle. STUDY FUNDING/COMPETING INTEREST(S) The study received no funding. C.M.B. is a member of the independent data monitoring group for a clinical endometriosis trial by ObsEva. He is on the scientific advisory board for Myovant and medical advisory board for Flo Health. He has received research grants from Bayer AG, MDNA Life Sciences, Volition Rx and Roche Diagnostics as well as from Wellbeing of Women, Medical Research Council UK, the NIH, the UK National Institute for Health Research and the European Union. He is the current Chair of the Endometriosis Guideline Development Group for ESHRE and was a co-opted member of the Endometriosis Guideline Group by the UK National Institute for Health and Care Excellence (NICE). I.G. has received research grants from Bayer AG, Wellbeing of Women, the European Union and Finox. TRIAL REGISTRATION NUMBER Not applicable.