Retinal microvasculature and time to pregnancy in a multi-ethnic pre-conception cohort in Singapore

STUDY QUESTION Can abnormalities in retinal microvasculature representing adverse microcirculatory perfusion and inflammation shed light on the pathophysiology of female fecundability? SUMMARY ANSWER In our prospective study, abnormalities in retinal vascular geometric morphology (i.e. sparser arteriolar fractal and larger venular bifurcation) during pre-conception phase are temporarily associated with a prolonged time-to-pregnancy (TTP). WHAT IS KNOWN ALREADY Suboptimal retinal microcirculatory morphology has been associated with obesity, psychological stress and hypertension, all of which are known risk factors for reduced female fecundability. STUDY DESIGN, SIZE, DURATION A total of 652 women of Chinese, Malay or Indian ethnicity 18–45 years of age and planning to conceive spontaneously within the next 12 months were recruited during the pre-conception period into the Singapore PREconception Study of long-Term maternal and child Outcomes (S-PRESTO), from February 2015 to October 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS During recruitment, we collected information on socio-demographic factors, menstrual characteristics and lifestyle behaviors and made anthropometric measurements. We assessed the following retinal microvascular features: caliber, branching angle and fractal dimension. We conducted follow-up telephone surveys to track each participant’s pregnancy status at 6, 9 and 12 months after enrolment. We ascertained clinical pregnancies via ultrasonography, with TTP measured by the number of menstrual cycles required to achieve a clinical pregnancy over a 1-year follow-up. Then, we performed discrete-time proportional hazards models to estimate the fecundability odds ratio (FOR) and 95% CI for each retinal microvascular feature in association with TTP, after adjusting for major confounders, including body mass index and fasting glycemic level at study entry. MAIN RESULTS AND THE ROLE OF THE CHANCE Among 652 recruited women, 276 (42.3%) successfully conceived within 1 year of follow-up. The mean (and SD) was 1.24 (0.05) Df for retinal arteriolar dimension fraction and 78.45 (9.79) degrees for retinal venular branching angle, respectively. Non-linear relationship testing was performed before multiple adjustment in all associations and a non-monotonic association was detected between retinal venular branching angle and TTP. Compared with women in the highest tertile of retinal arteriolar fractal dimension, women in the second tertile had a prolonged TTP (FOR: 0.68; 95% CI: 0.51–0.92), as did women in the lowest tertile (FOR: 0.73; 95% CI: 0.55–0.98). Compared with women in the middle tertile of retinal venular branching angle, women in the highest tertile had a borderline prolonged TTP (FOR: 0.75; 95% CI: 0.56–1.02). No other retinal vascular features were significantly associated with TTP. LIMITATIONS, REASONS FOR CAUTION We were unable to adjust for other potential confounding factors such as female sexual function (e.g. frequency of sexual intercourse), which might introduce a residual bias. Moreover, even though this is a prospective cohort design, our findings can identify the temporal relationship but not necessarily infer a causal relationship between maternal microvasculature and TTP. Lastly, our study involving mainly Chinese, Malay and Indian ethnicities might not be generalizable to other races or ethnicities. WIDER IMPLICATIONS OF THE FINDINGS Suboptimal microcirculation may lead to reduced female fecundability. In the future, in addition to conventional ultrasonographic evaluation of ovarian and uterine physiological function, assessing the retinal microvasculature might be useful for assessment of ovarian age, fertility prediction and endometrial evaluation before assisted reproductive techniques for fertility treatments. STUDY FUNDING/COMPETING INTEREST(S) This research is supported by the Singapore National Research Foundation (NRF) under its Translational and Clinical Research (TCR) Flagship Programme and administered by the Singapore Ministry of Health’s National Medical Research Council (NMRC) (Singapore-NMRC/TCR/004-NUS/2008; NMRC/TCR/012-NUHS/2014) and Singapore National Medical Research Council Transition Award (NMRC TA/0027/2014). The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER ClinicalTrials.gov, NCT03531658.

Drinking Water Arsenic and Adverse Reproductive Outcomes in Men and Women: A Systematic PRISMA Review

Infertility is a worldwide health issue, but mechanisms of both male and female reproductive toxicity remain to be elucidated. So far, a limited focus has been on potentially harmful environmental factors such as arsenic, which is naturally occurring in groundwater. The objective of this review was to systematically investigate the association between arsenic in drinking water and adverse reproductive outcomes in men and women of fertile age. We conducted a systematic literature search and included case-control studies and cohort studies reporting on decreased semen quality characteristics, increased time to pregnancy, infertility, or spontaneous abortion. In total, 433 articles were screened and ultimately, eight studies were included. Included literature was quality assessed with the Newcastle-Ottawa Scale. Findings were reported in a narrative synthesis. Only one study investigated male fertility. An association between increasing arsenic exposure and decreasing semen quality characteristics was found, as well as an indication of arsenic accumulation in seminal plasma. These findings are, however, at high arsenic levels (>1000 µg/L). No consistent evidence was found to support the hypothesis that arsenic exposure from drinking water is a cause of longer waiting time to pregnancy or spontaneous abortion, being the only endpoints investigated in the included literature. In conclusion; the evidence is sparse and of varying quality, however, it does warrant attention, as it conflicts with existing evidence, mainly from cross-sectional or ecologic studies.

P–787 Impact of delaying ART to promote weight loss: a large multicentre study accounting for the combined effect of female/male age and body mass index (BMI)

Study question Is postponing the start of ART (to promote a reduction in female BMI) beneficial for cumulative live birth rates (CLBR) when accounting for the female/male ageing this delay will cause? Summary answer Postponing ART treatment in one year to promote female weight loss could be detrimental in women of advanced maternal age (AMA, >35 years-old). What is known already Overweight/obese couples are frequently encouraged to lose weight prior to infertility treatment to enhance ART outcomes. However, a meaningful weight loss is often difficult to achieve for these couples, frequently taking at least one year to accomplish. Given that both female and male ageing are also important for ART success, we were interested in understanding the combined impact on CLBR of BMI reduction and ageing following a one-year delay. Study design, size, duration A retrospective study including patients performing their first ART cycle using autologous gametes between 2013–2018 in one of 39 participating ART centres. Only GnRH antagonist cycles were included (n = 14260). CLBR was the primary outcome. Secondary outcomes included time-to-pregnancy, birthweight and gestational age. Participants/materials, setting, methods Patients were subdivided according to female BMI (Kg/m2) in either underweight (<18.5), normal-weight (18.5–24.9), overweight (BMI 25.0–29.9 kg/m2) and obese (≥30 kg/m2). Meaningful and extreme weight loss were defined as a reduction from obesity to either overweight or normal-weight, respectively. We performed multivariable regression analysis to account for potential confounding. Main results and the role of chance Overweight (36.8%) and obese (33.0%) women had significantly lower CLBR when compared to the underweight (42.6%) and normal-weight (41.4%). When assessing the confounder-adjusted net-effect of male/female age and BMI, the predicted benefit of promoting a meaningful BMI reduction was lower than the estimated hindrance due to male/female ageing as soon as women reached AMA (n = 8365, 58.6%). This absence of benefit was especially important in women >38 years-old, in which even extreme weight-loss did not compensate for the age-related reduction in CLBR caused by the one-year delay. Moreover, male weight-loss failed to provide any additional benefit when accounted for in the regression models. Finally, obesity was also associated with a modest but statistically significant one-month delay in time-to-pregnancy and a 96.1 g (95% confidence interval: 39.9–152.4) increase in birth weight. The diagram of predicted outcomes presented in this study may serve as a useful tool to counsel patients before treatment, namely when recommending treatment postponement to promote short-term (i.e. 3–6 months) or long-term (i.e. 1 year) weight loss. Limitations, reasons for caution Caution is recommended when extrapolating these results into everyday practice owing to the retrospective nature of the study and the fact that only GnRH antagonist cycles were included. Wider implications of the findings: Patients are frequently confronted with the dilemma to either postpone treatment (and promote weight loss) or start treatment immediately (to avoid further ageing). Our results seem to show that women in AMA may have hindered CLBR if recommended to delay treatment even if the desired weight loss is ultimately achieved. Trial registration number Not applicable

P–751 Immediate versus postponed frozen-thawed embryo transfer after IVF/ICSI: a systematic review and meta-analysis

Study question Can frozen embryo transfer (FET) be offered immediately after a stimulated IVF/ICSI cycle without compromising live birth rate (LBR)? Summary answer FET in the menstrual cycle immediately following the stimulated IVF/ICSI cycle was associated with a slightly higher LBR compared to standard postponed FET. What is known already It is standard clinical practice to postpone FET for at least one menstrual cycle following a failed fresh transfer or a freeze-all cycle. This practice is thought to minimize any possible residual negative effect of ovarian stimulation, with excessive steroid levels and multiple corpora lutea, on the resumption of a normal ovulatory cycle and receptivity of the endometrium. Even so, elective deferral of FET is an empirical strategy based on suggestions rather than solid scientific evidence and may unnecessarily delay time to pregnancy, causing frustration and decreased quality of life to couples. Study design, size, duration Systematic review and meta-analysis according to PRISMA guidelines. Original studies on subfertile women aged 18–46 with any indication for treatment with IVF/ICSI investigating the timing of FET after IVF/ICSI were included. Intervention was defined as FET in the menstrual cycle immediately following the stimulated IVF/ICSI cycle. Comparator was defined as FET in the second or subsequent menstrual cycle following IVF/ICSI. Risk of bias was assessed using Robins-I and quality of evidence using GRADE. Participants/materials, setting, methods PubMed (MEDLINE) and EMBASE databases were searched for MeSH and Emtree terms, as well as text words related to timing of FET, up to March 2020. There were no limitations regarding year of publication or duration of follow-up but to English language. The primary outcome was LBR. Secondary outcomes were implantation rate, pregnancy rate, clinical pregnancy rate (CPR), time-to-pregnancy, miscarriage rate (MR), cycle cancellation rate and patient wellbeing. Main results and the role of chance Out of 4124 search results, 15 studies were included in the review. Studies reporting adjusted odds ratios (aOR) for LBR, CPR and MR were included in meta-analyses. All studies (n = 15) were retrospective cohort studies involving a total of 6,304 immediate FET cycles and 13,851 postponed FET cycles including 8,019 matched controls. Twelve studies of very low to moderate quality reported no difference in LBR with immediate versus postponed FET. Two studies of moderate quality reported a statistically significant increase in LBR with immediate FET and one small study of very low quality reported better LBR with postponed FET. Trends in rates of secondary outcomes followed trends in LBR regarding timing of FET. The meta-analyses showed a significant advantage of immediate FET (n = 2,076) compared to postponed FET (n = 3,833), with a pooled aOR of 1.20 (95% CI 1.01–1.44) for LBR and a pooled aOR of 1.22 (95% CI 1.07–1.39) for CPR. Limitations, reasons for caution: Limitations include the retrospective design and heterogeneity of studies included, limiting comparison and pooling of data. With little transparency regarding cancellation rates, the risk of selection bias is apparent. Further, confounding by embryo quality is a limitation. Small sample sizes are a limitation to subgroup meta-analyses. Wider implications of the findings: The standard clinical practice of postponing FET for at least one menstrual cycle following a failed fresh transfer or a freeze-all cycle may not be best clinical practice. Randomized controlled trials including data on cancellation rates are highly needed to provide high grade evidence regarding clinical practice and patient counseling. Trial registration number Not applicable

P–668 We aim for one baby, not one embryo: a personalized ET strategy based on embryo score and woman age maximizes LB and minimizes twins

Study question Is it possible to define a personalized ET model to maximize the chance of live birth (LB) while minimizing the risk of twin pregnancy? Summary answer A model including age and embryo morphological score can inform a personalized ET strategy to maximize LB while minimizing the risk of twin pregnancy. What is known already The morphological score of the transferred embryos affects pregnancy (PR) and LB rates in IVF cycles. Although SET is mainly recommended to avoid multiple pregnancies, DET is still being performed extensively, especially in patients with poor prognosis, with the aim to improve PR per transfer and shorten time to pregnancy. While twin pregnancies are associated with an increased risk of maternal and fetal complications, very low PR may increase patient drop-off, extend time to pregnancy, and increase the cost per successful transfer. A personalized transfer strategy balancing high LB per transfer with low twin pregnancy rates should be defined. Study design, size, duration Retrospective study including 2,470 fresh and frozen embryo transfers (ET) of either one or two embryos at D3 from January 2016 to August 2019 in a single IVF clinic. Biochemical, clinical, multiple pregnancy and live birth rates after SET and DET were analyzed according to the morphological score of the embryos transferred. ETs were divided into 9 groups according to the combinations of their embryo morphological scores. Participants/materials, setting, methods Embryos were assessed on D3 following a national recommended morphological scale. Morphology was categorized as High (H) if A or B+, medium (M) if B or C+, and Low (L) if C or D. The likelihood of biochemical, clinical pregnancy and live birth, and the risk of multiple pregnancy, after SET and DET of embryos of different scores was analyzed. A logistic regression analysis adjusted by age of the woman was ran for each outcome. Main results and the role of chance The distribution of ETs among the 9 groups for SET was: 510 H, 715 M, 346 L; for DET: 142 HH, 148 HM, 29 HL, 268 MM, 164 ML, 148 LL. Mean woman age was similar among groups: 38.7±4.01. Live birth and twin rates increased with embryo score. Considering a SET of category M as reference, the OR of live birth in DET were: 2.76 [1.82, 4.19 95%CI] for HH, and 2.32 [1.51, 3.55 95%CI] for HM, and 1.69 [1.19, 2.40 95%CI] for MM, and in SET: 1.52 [1.12, 2.04 95%CI] for H. Considering a DET of category MM as reference, the OR of twin birth in DET were: 2.8 [1.14, 6.99 95%CI] for HH, 2.5 [0.98, 6.46 95%CI] for HM, and 0.92 [0.11, 7.84 95%CI] for HL. According to this model, a 38y.o. woman with a SET of category M would have a 16% chance of live birth, and no twins. The addition of an M (DET: MM) increases her chance of live birth to 24% with a 2.9% risk of twins. The addition of a H (DET:MH) would increase further her chance of live birth to 30.8%, however, the increase would be due almost exclusively to twins (7%). Limitations, reasons for caution The limitations of this study are its retrospective nature and the small size of some categories. Embryos were classified using a national morphological scale; other morphological classifications could influence the results. The development and validation of site-specific models, using local patients’ data, is recommended before their use in clinical practice. Wider implications of the findings: A personalized assessment of embryo quality and woman age, at a minimum, are necessary to identify the best ET strategy for each patient; this strategy allows to maximize live birth rates while keeping the risk of twin birth as low as possibl. Trial registration number Not applicable

O-057 The impact of diagnosis endometriosis as part of the fertility workup

Abstract text The impact of diagnosis endometriosis as part of the Fertility workup Endometriosis is a multifaceted disease that may go from completely asymptomatic to a debilitating condition with severe pelvic pain complicated infertility. In the last few years, how we approach fertility in women with endometriosis has clearly changed, postponing definitive/radical surgery till the patient has completed her family. As a clear association exists with endometriosis and infertility, during the fertility workup it is one of the diseases to investigate, as it may have been missed in previous annual gynecologic checkups. Here we may face two problems: a) the stigma of diagnosis a young women with the label “endometriosis”, as she may be under the pressure of a progressive disease that may or may not affect her quality of life, and b) if the diagnosis of endometriosis is positive, how this may affect the decision making process during the fertility journey. In this lecture we will discuss the difficulties of early diagnosis of endometriosis, why most of the previous test have failed, and the new opportunity that miRNAs seem to offer. Once endometriosis is diagnosed –early or late stages- how this may affect spontaneous chances of pregnancy, ovarian reserve, oocyte and embryo quality, endometrial receptivity, and last but not least, time to pregnancy. Obviously, the prognosis changes over time, and women’s age will be conditioning most of our decisions. We will try to identify whom to treat, to increase the absolute pregnancy rate, and when to treat, to reduce the time to pregnancy. Finally, we will discuss the opportunity of fertility preservation in this particular subgroup of women. Being aware of the potential damage that endometriosis by itself, or the associated ovarian surgery, may inflict on ovarian reserve make these women more proactive for fertility preservation.

P–636 Anti-Müllerian-Hormone levels are not correlated to the probability of obtaining an ongoing pregnancy and time to pregnancy in women undergoing intra-uterine inseminations with donor sperm

Study question Is Anti-Müllerian hormone (AMH) level associated with the probability of obtaining an ongoing pregnancy (OP) and with time to pregnancy (TTP) in women undergoing d-IUI? Summary answer AMH is neither associated with the probability of obtaining an OP nor with time to pregnancy (TTP) in women undergoing d-IUI What is known already Anti-Müllerian hormone (AMH) is a glycoprotein produced by the granulosa cells of preantral and antral follicles. While AMH has been widely recognized as a quantitative marker of ovarian reserve used to predict ovarian responsiveness to ovarian stimulation in IVF, its relationship with fecundability in spontaneous conceptions is still a matter of debate. There is currently no consensus on the role of AMH on time to pregnancy in unassisted conceptions. The question of whether AMH is a qualitative marker of oocyte quality is therefore still unanswered. Study design, size, duration This prospective cohort study was carried out between 9/1/2017 and 12/30/2020 on 592 women aged 19 to 44, who underwent d-IUI in a natural cycle (n = 1788) the day after LH peak. Patients were single, homosexual, or heterosexual with an infertile partner and underwent 1 to maximum 6 d-IUI. All patients had regular ovulatory cycles and bilateral tubal patency confirmed before starting d-IUI. AMH evaluation was performed within the previous 3 months of the first d-IUI. Participants/materials, setting, methods The primary outcomes were the likelihood of obtaining an OP (>14 weeks) and TTP calculated as the number of d-IIU up to an OP. Multivariate logistic regression was used to compare the probability of obtaining an OP according to age and AMH levels. Kaplan-Meier curves with log-rank test were used to assess the TTP stratified by age groups (≤35, >35 to ≤ 39, and > 39 years old) and AMH groups (< 1ng/mL and ≥ 1ng/mL). Main results and the role of chance AMH levels were negatively correlated with age (p < 0.001). OP were significantly lower with increasing age (OR 0.92 (0.89–0.95) p < 0.001) but did not differ according to AMH levels (OR 1.07 (0.97–1.18) p = 0.18). When adjusting for AMH, the association between age and OP remained significant (OR 0.91 (0.88–0.95)). TTP was significantly different between age groups: ≤35 years old (n = 338), >35 to ≤ 39 years old (n = 136) and > 39 years old (n = 118) (p < 0.001), but did not differ significantly according to AMH levels < 1ng/mL (n = 130) and ≥1ng/mL (n = 462)(p = 0.55). Limitations, reasons for caution Our results concern d-IUI and can therefore not be extrapolated to natural conception. However, the study model is close to natural fecundity as there was no history of female infertility and as all IUI were performed on the day of ovulation with donor sperm proven to be fertile. Wider implications of the findings: While measuring AMH seems necessary for gonadotropin dose adjustment in ART, our data suggest that it cannot qualitatively assess fertility outcome and should therefore not be used routinely for preconception counseling in the absence of infertility history. Trial registration number P2017/396