Higher incidence of embryonic defects in mouse offspring conceived with assisted reproduction from fathers with sperm epimutations.

Assisted reproductive technologies (ART) account for 1-6% of births in developed countries. While most children conceived are healthy, increases in birth and genomic imprinting defects have been reported; such abnormal outcomes have been attributed to underlying parental infertility and/or the ART used. Here, we assessed whether paternal genetic and lifestyle factors, that are associated with male infertility and affect the sperm epigenome, can influence ART outcomes. We examined how paternal factors, haploinsufficiency for Dnmt3L, an important co-factor for DNA methylation reactions, and/or diet-induced obesity, in combination with ART (superovulation, in vitro fertilization, embryo culture and embryo transfer), could adversely influence embryo development and DNA methylation patterning in mice. While male mice fed high-fat diets (HFD) gained weight and showed perturbed metabolic health, their sperm DNA methylation was minimally affected by the diet. In contrast, Dnmt3L haploinsufficiency induced a marked loss of DNA methylation in sperm; notably, regions affected were associated with neurodevelopmental pathways and enriched in young retrotransposons, sequences that can have functional consequences in the next generation. Following ART, placental imprinted gene methylation and growth parameters were impacted by one or both paternal factors. For embryos conceived by natural conception, abnormality rates were similar for WT and Dnmt3L+/- fathers. In contrast, paternal Dnmt3L+/- genotype, as compared to WT fathers, resulted in a 3-fold increase in the incidence of morphological abnormalities in embryos generated by ART. Together, the results indicate that embryonic morphological and epigenetic defects associated with ART may be exacerbated in offspring conceived by fathers with sperm epimutations.

Methyltransferase-like 3 mediated RNA m6 A modifications in the reproductive system: Potentials for diagnosis and therapy.

Several studies have highlighted the functional indispensability of methyltransferase-like 3 (METTL3) in the reproductive system. However, a review that comprehensively interprets these studies and elucidates their relationships is lacking. Therefore, the present work aimed to review studies that have investigated the functions of METTL3 in the reproductive system (including spermatogenesis, follicle development, gametogenesis, reproductive cancer, asthenozoospermia and assisted reproduction failure). This review suggests that METTL3 functions not only essential for normal development, but also detrimental in the occurrence of disorders. In addition, promising applications of METTL3 as a diagnostic or prognostic biomarker and therapeutic target for reproductive disorders have been proposed. Collectively, this review provides comprehensive interpretations, novel insights, potential applications and future perspectives on the role of METTL3 in regulating the reproductive system, which may be a valuable reference for researchers and clinicians.

Assisted reproductive technology use and outcomes in childhood cancer survivors.

BACKGROUND: Treatment exposures for childhood cancer reduce ovarian reserve. However, the success of assisted reproductive technology (ART) among female survivors is not well established. METHODS: Five-year survivors of childhood cancer in the Childhood Cancer Survivor Study were linked to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System, which captures national ART outcomes. The authors assessed the live birth rate, the relative risk (RR) with 95% confidence intervals (95% CIs), and associations with treatment exposure using generalized estimating equations to account for multiple ovarian stimulations per individual. Siblings from a random sample of survivors were recruited to serve as a comparison group. RESULTS: Among 9885 female survivors, 137 (1.4%; median age at diagnosis, 10 years [range, 0-20 years]; median years of follow-up after age 18 years, 11 years [range, 2-11 years]) underwent 224 ovarian stimulations using autologous or donor eggs and/or gestational carriers (157 autologous ovarian stimulation cycles, 67 donor ovarian stimulation cycles). In siblings, 33 (1.4%) underwent 51 autologous or donor ovarian stimulations. Of those who used embryos from autologous eggs without using gestational carriers, 97 survivors underwent 155 stimulations, resulting in 49 live births, for a 31.6% chance of live birth per ovarian stimulation (vs. 38.3% for siblings; p = .39) and a 43.9% chance of live birth per transfer (vs. 50.0%; p = .33). Prior treatment with cranial radiation therapy (RR, 0.44; 95% CI, 0.20-0.97) and pelvic radiation therapy (RR, 0.33; 95% CI, 0.15-0.73) resulted in a reduced chance of live birth compared with siblings. The likelihood of live birth after ART treatment in survivors was not affected by alkylator exposure (cyclophosphamide-equivalent dose, ≥8000 mg/m2 vs. none; RR, 1.04; 95% CI, 0.52-2.05). CONCLUSIONS: Childhood cancer survivors are as likely to undergo treatment using ART as sibling controls. The success of ART treatment was not reduced after alkylator exposure. The results from the current study provide needed guidance on the use of ART in this population.

Cardiovascular autonomic nervous function in children conceived by assisted reproductive technology with frozen or fresh embryo transfer.

As a result of epigenetic changes, children conceived by assisted reproduction may be at risk of premature cardiovascular aging with notably increased blood pressures. Their cardiovascular autonomic nervous function is unknown. Therefore, this study investigated the cardiovascular autonomic nervous function in 8-12-yr-old children (51% girls) conceived naturally (n = 33) or by assisted reproduction with frozen (n = 34) or fresh (n = 38) embryo transfer by evaluating heart rate variability, during rest; from provocation maneuvers; and from baroreflex function. Heart rate and blood pressure response to provocation maneuvers and baroreflex function were comparable between children conceived naturally or by assisted reproduction. The mean RR-interval and high-frequency component of heart rate variability were lower in children conceived by assisted reproduction than in children conceived naturally. Children conceived by fresh embryo transfer had ∼17% lower heart rate-corrected standard deviation of normal-to-normal R-R intervals; ∼22% lower heart rate-corrected square root of the mean of the squared difference between successive R-R intervals; and ∼37% higher low-frequency/high-frequency ratio than naturally conceived children. Children conceived by assisted reproduction still had lower heart rate variability and vagal modulation than naturally conceived children after adjustment for confounders. Thus, these results raise the possibility of sympathetic predominance in children conceived by assisted reproduction. Therefore, it is important to reproduce these results in larger and older cohorts as sympathetic predominance relates with cardiovascular and metabolic diseases.NEW & NOTEWORTHY We observed that children conceived by assisted reproductive technology (both frozen and fresh embryo transfer) had lowered heart rate variability during rest as compared with children conceived naturally. During physiological stress maneuvers, however, the cardiovascular autonomic nervous regulation was comparable between children conceived by assisted reproductive technologies and naturally. Our findings highlight the potential that lowered heart rate variability during rest in children conceived by assisted reproductive technologies may precede premature hypertension.

Magnetotactic Sperm Cells for Assisted Reproduction.

Biohybrid micromotors are active microscopic agents consisting of biological and synthetic components that are being developed as novel tools for biomedical applications. By capturing motile sperm cells within engineered microstructures, they can be controlled remotely while being propelled forward by the flagellar beat. This makes them an interesting tool for reproductive medicine that can enable minimally invasive sperm cell delivery to the oocyte in vivo, as a treatment for infertility. The generation of sperm-based micromotors in sufficiently large numbers, as they are required in biomedical applications has been challenging, either due to the employed fabrication techniques or the stability of the microstructure-sperm coupling. Here, biohybrid micromotors, which can be assembled in a fast and simple process using magnetic microparticles, are presented. These magnetotactic sperm cells show a high motility and swimming speed and can be transferred between different environments without large detrimental effects on sperm motility and membrane integrity. Furthermore, clusters of micromotors are assembled magnetically and visualized using dual ultrasound (US)/photoacoustic (PA) imaging. Finally, a protocol for the scaled-up assembly of micromotors and their purification for use in in vitro fertilization (IVF) is presented, bringing them closer to their biomedical implementation.

Pregnancy in antiphospholipid syndrome: what should a rheumatologist know?

This review focuses on the management of reproductive issues in women who have antiphospholipid syndrome (APS) or are carriers of antiphospholipid antibodies (aPL). The importance of aPL detection during preconception counselling relies on their pathogenic potential for placental insufficiency and related obstetric complications. The risk of adverse pregnancy outcomes can be minimized by individualized risk stratification and tailored treatment aimed at preventing placental insufficiency. Combination therapy of low-dose acetylsalicylic acid and heparin is the mainstay of prophylaxis during pregnancy; immunomodulation, especially with hydroxychloroquine, should be considered in refractory cases. Supplementary ultrasound surveillance is useful to detect fetal growth restriction and correctly tailor the time of delivery. The individual aPL profile must be considered in the stratification of thrombotic risk, such as during assisted reproduction techniques requiring hormonal ovarian stimulation or during the follow-up after pregnancy in order to prevent the first vascular event.

Estimating the impact of bias in causal epidemiological studies: the case of health outcomes following assisted reproduction.

Researchers interested in causal questions must deal with two sources of error: random error (random deviation from the true mean value of a distribution), and bias (systematic deviance from the true mean value due to extraneous factors). For some causal questions, randomization is not feasible, and observational studies are necessary. Bias poses a substantial threat to the validity of observational research and can have important consequences for health policy developed from the findings. The current piece describes bias and its sources, outlines proposed methods to estimate its impacts in an observational study, and demonstrates how these methods may be used to inform debate on the causal relationship between medically assisted reproduction (MAR) and health outcomes, using cancer as an example. In doing so, we aim to enlighten researchers who work with observational data, especially regarding the health effects of MAR and infertility, on the pitfalls of bias, and how to address them. We hope that, in combination with the provided example, we can convince readers that estimating the impact of bias in causal epidemiologic research is not only important but necessary to inform the development of robust health policy and clinical practice recommendations.

Gender inequality and utilization of ART: an international cross-sectional and longitudinal analysis.

STUDY QUESTION: What is the association between a country's level of gender equality and access to ART, as measured through ART utilization? SUMMARY ANSWER: ART utilization is associated with a country's level of gender equality even after controlling for the level of development. WHAT IS KNOWN ALREADY: Although gender equality is recognized as an important determinant of population health, its association with fertility care, a highly gendered condition, has not been explored. STUDY DESIGN, SIZE, DURATION: A longitudinal cross-national analysis of ART utilization in 69 countries during 2002-2014 was carried out. PARTICPANTS/MATERIALS, SETTING, METHODS: The Gender Inequality Index (GII), Human Development Index (HDI), and their component indicators were modelled against ART utilization using univariate regression models as well as mixed-effects regression methods (adjusted for country, time, and economic/human development) with multiple imputation to account for missing data. MAIN RESULTS AND THE ROLE OF CHANCE: ART utilization is associated with the GII. In an HDI-adjusted analysis, a one standard deviation decrease in the GII (towards greater equality) is associated with a 59% increase in ART utilization. Gross national income per capita, the maternal mortality ratio, and female parliamentary representation were the index components most predictive of ART utilization. LIMITATIONS, REASONS FOR CAUTION: Only ART was used rather than all infertility treatments (including less costly and non-invasive treatments such as ovulation induction). This was a country-level analysis and the results cannot be generalized to smaller groups. Not all modelled variables were available for each country across 2002-2014. WIDER IMPLICATIONS OF THE FINDINGS: Access to fertility care is central to women's sexual and reproductive health, to women's rights, and to human rights. As gender equality improves, so does access to ART. This relation is likely to be reinforcing and bi-directional, with progress towards global, equitable access to fertility care also improving women's status and participation in societies. STUDY FUNDING/COMPETING INTEREST(S): External funding was not provided for this study. G.D.A. declares consulting fees from Labcorp and CooperSurgical. G.D.A. is the founder and CEO of Advanced Reproductive Care, Inc., as well as the Chair of the International Committee for Monitoring Assisted Reproductive Technologies (ICMART) and the World Endometriosis Research Foundation, both of which are unpaid roles. G.M.C. is an ICMART Board Representative, which is an unpaid role, and no payments are received from ICMART to UNSW, Sydney, or to G.M.C. to undertake this study. O.F., S.D., F.Z.-H., and E.K. report no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

An ESHG-ESHRE survey on the current practice of expanded carrier screening in medically assisted reproduction.

STUDY QUESTION: What is the current practice and views on (expanded) carrier screening ((E)CS) among healthcare professionals in medically assisted reproductive (MAR) practices in Europe? SUMMARY ANSWER: The findings show a limited support for ECS with less than half of the respondents affiliated to centres offering ECS, and substantial variation in practice between centres in Europe. WHAT IS KNOWN ALREADY: The availability of next-generation sequencing, which enables testing for large groups of genes simultaneously, has facilitated the introduction and expansion of ECS strategies, currently offered particularly in the private sector in the context of assisted reproduction. STUDY DESIGN, SIZE, DURATION: A cross-sectional survey evaluating practice and current views among professionals working in MAR practice in different European countries was designed using the online SurveyMonkey tool. The web-based questionnaire included questions on general information regarding the current practice of (E)CS in MAR and questions on what is offered, to whom the test is offered, and how it is offered. It consisted mostly of multiple-choice questions with comment boxes, but also included open questions on the respondents' attitudes/concerns relevant to (E)CS practice, and room to upload requested files (e.g. guidelines and gene panels). In total, 338 responses were collected from 8 February 2022 to 11 April 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: The online survey was launched with an invitation email from the ESHRE central office (n = 4889 emails delivered) and the European Society of Human Genetics (ESHG) central office (n = 1790 emails delivered) sent to the ESHRE and ESHG members, and by social media posts. The survey was addressed to European MAR centres or gamete banks and to centres located in non-European countries participating in the European IVF-monitoring Consortium. Two reminder emails were sent. After exclusion of 39 incomplete responses received (e.g. only background information), 299 respondents from 40 different countries were included for analyses. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 42.5% (127/299) of respondents were affiliated to centres offering ECS. The perceived responsibility to enable prospective parents to make informed reproductive decisions and preventing suffering/burden for parents were the main reasons to offer ECS. A single ECS panel is offered by nearly 45% (39/87 received answers) of the centres offering ECS, 25.3% (22/87) of those centres offer a selection of ECS panels, and 29.9% (26/87) offer whole exome sequencing and a large in silico panel. Different ranges of panel sizes and conditions were included in the ECS panel(s) offered. Most of the respondents (81.8%; 72/88 received answers) indicated that the panels they offer are universal and target the entire population. Pathogenic variants (89.7%; 70/78 received answers), and to a lesser extent, likely pathogenic variants (64.1%%; 50/78 received answers), were included in the ECS report for individuals and couples undergoing MAR with their own gametes. According to 87.9% (80/91 received answers) of the respondents, patients have to pay to undergo an ECS test. Most respondents (76.2%; 61/80 received answers) reported that counselling is provided before and after the ECS test. Preimplantation genetic testing, the use of donor gametes, and prenatal diagnostic testing were the three main reproductive options discussed with identified carrier couples. The main reason, according to the respondents, for not offering ECS in their centre, was the lack of professional recommendations supporting ECS (52.5%; 73/139 received answers) and the high cost for couples or reimbursement not being available (49.6%; 69/139). The challenges and moral dilemmas encountered by the respondents revolved mainly around the content of the offer, including the variants classification and the heterogeneity of the panels, the counselling, and the cost of the test. LIMITATIONS, REASONS FOR CAUTION: Although the total number of respondents was acceptable, the completion rate of the survey was suboptimal. In addition, the heterogeneity of answers to open-ended questions and the ambiguity of some of the answers, along with incomplete responses, posed a challenge in interpreting survey results. It is also plausible that some questions were not easily understood by the respondents. For this reason, response and non-response bias are acknowledged as further limitations of the survey. WIDER IMPLICATIONS OF THE FINDINGS: The results of this survey could aid in identifying potential challenges or areas for improvement in the current practice of ECS in the MAR field and contribute to the discussion on how to address them. The results underline the need to stimulate a more knowledge-based debate on the complexity and the pros and cons of a possible implementation of ECS in MAR. STUDY FUNDING/COMPETING INTEREST(S): All costs relating to the development process were covered from European Society of Human Reproduction and Embryology and European Society of Human Genetics funds. There was no external funding of the development process or manuscript production. A.C. is full-time employee of Juno Genetics. L.H. declared receiving a research grant during the past 36 months from the Netherlands Organisation for Health Research and Development. She has also participated in a Health Council report of the Netherlands on preconception carrier screening and collaborated with the VSOP Dutch Genetic Alliance (patient umbrella organization on rare and genetic disorders). L.H. and C.v.E. are affiliated with Amsterdam University Medical Centre, a hospital that offers ECS in a non-commercial setting. R.V. received honoraria for presentations from Merck Academy and is unpaid board member of the executive committee of the Spanish Fertility Society. The other authors had nothing to disclose. TRIAL REGISTRATION NUMBER: N/A.

Does recurrent implantation failure exist? Prevalence and outcomes of five consecutive euploid blastocyst transfers in 123 987 patients.

STUDY QUESTION: What are the clinical pregnancy and live birth rates in women who underwent up to two more euploid blastocyst transfers after three failures in the absence of another known factor that affects implantation? SUMMARY ANSWER: The fourth and fifth euploid blastocyst transfers resulted in similar live birth rates of 40% and 53.3%, respectively, culminating in a cumulative live birth rate of 98.1% (95% CI = 96.5-99.6%) after five euploid blastocyst transfers. WHAT IS KNOWN ALREADY: The first three euploid blastocysts have similar implantation and live birth rates and provide a cumulative live birth rate of 92.6%. STUDY DESIGN, SIZE, DURATION: An international multi-center retrospective study was conducted at 25 individual clinics. The study period spanned between January 2012 and December 2022. A total of 123 987 patients with a total of 64 572 euploid blastocyst transfers were screened for inclusion. PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients with a history of any embryo transfer at another clinic, history of any unscreened embryo transfer at participating clinics, parental karyotype abnormalities, the use of donor oocytes or a gestational carrier, untreated intracavitary uterine pathology (e.g. polyp, leiomyoma), congenital uterine anomalies, adenomyosis, communicating hydrosalpinx, endometrial thickness <6 mm prior to initiating of progesterone, use of testicular sperm due to non-obstructive azoospermia in the male partner, transfer of an embryo with a reported intermediate chromosome copy number (i.e. mosaic), preimplantation genetic testing cycles for monogenic disorders, or structural chromosome rearrangements were excluded. Ovarian stimulation protocols and embryology laboratory procedures including trophectoderm biopsy followed the usual practice of each center. The ploidy status of blastocysts was determined with comprehensive chromosome screening. Endometrial preparation protocols followed the usual practice of participating centers and included programmed cycles, natural or modified natural cycles. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 105 (0.085% of the total population) patients met the criteria and underwent at least one additional euploid blastocyst transfer after failing to achieve a positive pregnancy test with three consecutive euploid blastocyst transfers. Outcomes of the fourth and fifth euploid blastocyst transfers were similar across participating centers. Overall, the live birth rate was similar with the fourth and fifth euploid blastocysts (40% vs 53.3%, relative risk = 1.33, 95% CI = 0.93-1.9, P value = 0.14). Sensitivity analyses excluding blastocysts biopsied on Day 7 postfertilization, women with a BMI >30 kg/m2, cycles using non-ejaculate or donor sperm, double-embryo transfer cycles, and cycles in which the day of embryo transfer was modified due to endometrial receptivity assay test result yielded similar results. Where data were available, the fourth euploid blastocyst had similar live birth rate with the first one (relative risk = 0.84, 95% CI = 0.58-1.21, P = 0.29). The cumulative live birth rate after five euploid blastocyst transfers was 98.1% (95% CI = 96.5-99.6%). LIMITATIONS, REASONS FOR CAUTION: Retrospective design has its own inherent limitations. Patients continuing with a further euploid embryo transfer and patients dropping out from treatment after three failed euploid transfers can be systematically different, perhaps with regard to ovarian reserve or economic status. WIDER IMPLICATION OF THE FINDINGS: Implantation failure seems to be mainly due to embryonic factors. Given the stable and high live birth rates up to five euploid blastocysts, unexplained recurrent implantation failure should have a prevalence of <2%. Proceeding with another embryo transfer can be the best next step once a known etiology for implantation failure is ruled out. STUDY FUNDING/COMPETING INTEREST(S): None. TRIAL REGISTRATION NUMBER: N/A.

Using the theory of planned behavior to predict parents' disclosure of donor conception to their children: a longitudinal study.

STUDY QUESTION: Can the application of the theory of planned behavior (TPB) help predict heterosexual parents' disclosure of donor conception to their children? SUMMARY ANSWER: Parents with a stronger will to act in accordance with social norms favoring disclosure were more likely to start the disclosure process within the next 5-9 years. WHAT IS KNOWN ALREADY: In contrast to single mothers by choice and same-sex couples, heterosexual couples need to make an active decision to disclose their use of donor conception to their child. While disclosure at an early age is encouraged by international guidelines, many heterosexual-couple parents struggle with this. A previous study has found an association between parental scores of TPB factors and disclosure intention, but so far, no study has applied the TPB to predict parents' disclosure behavior. STUDY DESIGN, SIZE, DURATION: The present study is based on the fourth and fifth waves of data collection (T4 and T5) in a nation-wide longitudinal study. Participating parents had conceived through identity-release oocyte donation (n = 68, response rate 65%) and sperm donation (n = 62, response rate 56%) as part of a heterosexual couple. PARTICIPANTS/MATERIALS, SETTING, METHODS: The present study is part of the prospective longitudinal Swedish Study on Gamete Donation (SSGD). Consecutive recruitment of couples starting oocyte or sperm donation treatment was conducted at all seven fertility clinics providing gamete donation in Sweden during a 3-year period (2005-2008). Participants were requested to complete postal surveys at five time points. The present study includes heterosexual-couple parents following oocyte or sperm donation who participated at the two latest time points when their children were 7-8 years old (T4), and 13-17 years old (T5). At T4, participants completed the study-specific TPB Disclosure Questionnaire (TPB-DQ) measuring attitudes and intentions to disclose the donor conception to the child, and disclosure behavior was assessed at both T4 and T5. Data from those participants who had not yet disclosed at T4 were analyzed using survival analysis with Cox regressions. MAIN RESULTS AND THE ROLE OF CHANCE: Forty participants had not disclosed the donor conception to their children at T4 and, out of these, 13 had still not disclosed at T5. We found a significant association between scores of the TPB factor Subjective norms at T4 and their subsequent disclosure behavior at T5 (HR = 2.019; 95% CI: 1.36-3.01). None of the other factors were significantly associated with disclosure behavior. LIMITATIONS, REASONS FOR CAUTION: The present study concerns heterosexual-couple parents with children conceived following treatment with gametes from open-identity donors, which limits the generalizability of our findings to other groups and contexts. Other limitations include the risk of systematic attrition due to the longitudinal study design and decreased statistical power due to few participants. WIDER IMPLICATIONS OF THE FINDINGS: Our findings highlight the importance of perceived subjective norms for parents' disclosure behavior and indicate that the co-parent's opinion about disclosure is of particular relevance in this regard. Counselors should focus on supporting prospective parents to initiate and maintain a healthy and open dialogue about concerns around building a family with donor conception. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by the Swedish Research Council. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: N/A.

Differences in medically assisted reproduction use by sexual identity and partnership: a prospective cohort of cisgender women.

STUDY QUESTION: Does medically assisted reproduction (MAR) use among cisgender women differ among those with same-sex partners or lesbian/bisexual identities compared to peers with different-sex partners or heterosexual identities? SUMMARY ANSWER: Women with same-sex partners or lesbian/bisexual identities are more likely to utilize any MAR but are no more likely to use ART (i.e. IVF, reciprocal IVF, embryo transfer, unspecified ART, ICSI, and gamete or zygote intrafallopian transfer) compared to non-ART MAR (i.e. IUI, ovulation induction, and intravaginal or intracervical insemination) than their different-sex partnered and completely heterosexual peers. WHAT IS KNOWN ALREADY: Sexual minority women (SMW) form families in myriad ways, including through fostering, adoption, genetic, and/or biological routes. Emerging evidence suggests this population increasingly wants to form genetic and/or biological families, yet little is known about their family formation processes and conception needs. STUDY DESIGN, SIZE, DURATION: The Growing Up Today Study is a US-based prospective cohort (n = 27 805). Participants were 9-17 years of age at enrollment (1996 and 2004). Biennial follow-up is ongoing, with data collected through 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cisgender women who met the following criteria were included in this sample: endorsed ever being pregnant; attempted a pregnancy in 2019 or 2021; and endorsed either a male- or female-sex partner OR responded to questions regarding their sexual identity during their conception window. The main outcome was any MAR use including ART (i.e. procedures involving micromanipulation of gametes) and non-ART MAR (i.e. nonmanipulation of gametes). Secondary outcomes included specific MAR procedures, time to conception, and trends across time. We assessed differences in any MAR use using weighted modified Poisson generalized estimating equations. MAIN RESULTS AND THE ROLE OF CHANCE: Among 3519 participants, there were 6935 pregnancies/pregnancy attempts and 19.4% involved MAR. A total of 47 pregnancies or pregnancy attempts were among the same-sex partnered participants, while 91 were among bisexual participants and 37 among lesbian participants. Participants with same-sex, compared to different-sex partners were almost five times as likely to use MAR (risk ratio [95% CI]: 4.78 [4.06, 5.61]). Compared to completely heterosexual participants, there was greater MAR use among lesbian (4.00 [3.10, 5.16]) and bisexual (2.22 [1.60, 3.07]) participants compared to no MAR use; mostly heterosexual participants were also more likely to use ART (1.42 [1.11, 1.82]) compared to non-ART MAR. Among first pregnancies conceived using MAR, conception pathways differed by partnership and sexual identity groups; differences were largest for IUI, intravaginal insemination, and timed intercourse with ovulation induction. From 2002 to 2021, MAR use increased proportionally to total pregnancies/pregnancy attempts; ART use was increasingly common in later years among same-sex partnered and lesbian participants. LIMITATIONS, REASONS FOR CAUTION: Our results are limited by the small number of SMW, the homogenous sample of mostly White, educated participants, the potential misclassification of MAR use when creating conception pathways unique to SMW, and the questionnaire's skip logic, which excluded certain participants from receiving MAR questions. WIDER IMPLICATIONS OF THE FINDINGS: Previous studies on SMW family formation have primarily focused on clinical outcomes from ART procedures and perinatal outcomes by conception method, and have been almost exclusively limited to European, clinical samples that relied on partnership data only. Despite the small sample of SMW within a nonrepresentative study, this is the first study to our knowledge to use a nonclinical sample of cisgender women from across the USA to elucidate family formation pathways by partnership as well as sexual identity, including pathways that may be unique to SMW. This was made possible by our innovative approach to MAR categorization within a large, prospective dataset that collected detailed sexual orientation data. Specifically, lesbian, bisexual, and same-sex partnered participants used both ART and non-ART MAR at similar frequencies compared to heterosexual and different-sex partnered participants. This may signal differential access to conception pathways owing to structural barriers, emerging conception trends as family formation among SMW has increased, and a need for conception support beyond specialized providers and fertility clinics. STUDY FUNDING/COMPETING INTEREST(S): The research reported in this publication was supported by the National Institute on Minority Health and Health Disparities of the National Institutes of Health (NIH), under award number R01MD015256. Additionally, KRSS is supported by NCI grant T32CA009001, AKH by the NCI T32CA057711, PC by the NHLBI T32HL098048, BM by the Stanford Maternal Child Health Research Institute Clinical Trainee Support Grant and the Diversity Fellowship from the American Society for Reproductive Medicine Research Institute, BGE by NICHD R01HD091405, and SM by the Thomas O. Pyle Fellowship through the Harvard Pilgrim Health Care Foundation and Harvard University, NHLBI T32HL098048, NIMH R01MH112384, and the William T. Grant Foundation grant number 187958. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The first author recently had a leadership role in the not-for-profit program, The Lesbian Health Fund, a research fund focused on improving the health and wellbeing of LGBTQ+ women and girls. The fund did not have any role in this study and the author's relationship with the fund did not bias the findings of this manuscript. TRIAL REGISTRATION NUMBER: N/A.

Identification of two hidden clinical subgroups among men with idiopathic cryptozoospermia.

STUDY QUESTION: Are there subgroups among patients with cryptozoospermia pointing to distinct etiologies? SUMMARY ANSWER: We reveal two distinct subgroups of cryptozoospermic (Crypto) patients based on testicular tissue composition, testicular volume, and FSH levels. WHAT IS KNOWN ALREADY: Cryptozoospermic patients present with a sperm concentration below 0.1 million/ml. While the etiology of the severely impaired spermatogenesis remains largely unknown, alterations of the spermatogonial compartment have been reported including a reduction of the reserve stem cells in these patients. STUDY DESIGN, SIZE, DURATION: To assess whether there are distinct subgroups among cryptozoospermic patients, we applied the statistical method of cluster analysis. For this, we retrospectively selected 132 cryptozoospermic patients from a clinical database who underwent a testicular biopsy in the frame of fertility treatment at a university hospital. As controls (Control), we selected 160 patients with obstructive azoospermia and full spermatogenesis. All 292 patients underwent routine evaluation for endocrine, semen, and histological parameters (i.e. the percentage of tubules with elongated spermatids). Moreover, outcome of medically assisted reproduction (MAR) was assessed for cryptozoospermic (n = 73) and Control patients (n = 87), respectively. For in-depth immunohistochemical and histomorphometrical analyses, representative tissue samples from cryptozoospermic (n = 27) and Control patients (n = 12) were selected based on cluster analysis results and histological parameters. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study included two parts: firstly using clinical parameters of the entire cohort of 292 patients, we performed principal component analysis (PCA) followed by hierarchical clustering on principal components (i.e. considering hormonal values, ejaculate parameters, and histological information). Secondly, for histological analyses seminiferous tubules were categorized according to the most advanced germ cell type present in sections stained with Periodic acid Schif. On the selected cohort of 39 patients (12 Control, 27 cryptozoospermic), we performed immunohistochemistry for spermatogonial markers melanoma-associated antigen 4 (MAGEA4) and piwi like RNA-mediated gene silencing 4 (PIWIL4) followed by quantitative analyses. Moreover, the morphologically defined Adark spermatogonia, which are considered to be the reserve stem cells, were quantified. MAIN RESULTS AND THE ROLE OF CHANCE: The PCA and hierarchical clustering revealed three different clusters, one of them containing all Control samples. The main factors driving the sorting of patients to the clusters were the percentage of tubules with elongated spermatids (Cluster 1, all Control patients and two cryptozoospermic patients), the percentage of tubules with spermatocytes (Cluster 2, cryptozoospermic patients), and tubules showing a Sertoli cells only phenotype (Cluster 3, cryptozoospermic patients). Importantly, the percentage of tubules containing elongated spermatids was comparable between Clusters 2 and 3. Additional differences were higher FSH levels (P < 0.001) and lower testicular volumes (P < 0.001) in Cluster 3 compared to Cluster 2. In the spermatogonial compartment of both cryptozoospermic Clusters, we found lower numbers of MAGEA4+ and Adark spermatogonia but higher proportions of PIWIL4+ spermatogonia, which were significantly correlated with a lower percentage of tubules containing elongated spermatids. In line with this common alteration, the outcome of MAR was comparable between Controls as well as both cryptozoospermic Clusters. LIMITATIONS, REASONS FOR CAUTION: While we have uncovered the existence of subgroups within the cohort of cryptozoospermic patients, comprehensive genetic analyses remain to be performed to unravel potentially distinct etiologies. WIDER IMPLICATIONS OF THE FINDINGS: The novel insight that cryptozoospermic patients can be divided into two subgroups will facilitate the strategic search for underlying genetic etiologies. Moreover, the shared alterations of the spermatogonial stem cell compartment between the two cryptozoospermic subgroups could represent a general response mechanism to the reduced output of sperm, which may be associated with a progressive phenotype. This study therefore offers novel approaches towards the understanding of the etiology underlying the reduced sperm formation in cryptozoospermic patients. STUDY FUNDING/COMPETING INTEREST(S): German research foundation CRU 326 (grants to: SDP, NN). Moreover, we thank the Faculty of Medicine of the University of Münster for the financial support of Lena Charlotte Schülke through the MedK-program. We acknowledge support from the Open Access Publication Fund of the University of Münster. The authors have no potential conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Moonshots and last miles: what it may take to treat infertility for all.

Innovation in medically assisted reproduction (MAR) is at an all-time high, with new technologies being developed for the laboratory and around the patient experience, and deployed quickly and effectively. Nevertheless, substantial improvements in the success of infertility care seem to elude the field. This article presents the view that MAR is missing the key innovation motor of mechanistic knowledge, which historically relates to a lack of public resources of the kind afforded to other diseases. It is posited that unless and until we raise infertility at the level of an urgent unmet medical need in the eyes of government and national funding body, innovation will be limited in scope and impact, and be incremental in nature.

Endometrial preparation protocols prior to frozen embryo transfer - convenience or safety?

The number of frozen embryo transfer (FET) cycles is increasing rapidly worldwide. Different endometrial preparations for FET result in comparable live birth rates. However, several recent publications have reported higher maternal risks for hypertensive disorders of pregnancy (HDP), pre-eclampsia and postpartum haemorrhage (PPH) in programmed cycles (PC-FET) compared with natural cycles and modified natural cycles with an intact corpus luteum. Nevertheless, PC-FET is frequently used in ovulatory women despite the increased risks for HDP, pre-eclampsia and PPH. Although randomized controlled studies have been suggested, PC-FET raises several methodological problems. Large study populations would be required to investigate the outcomes in question, and the inclusion of ovulatory women, where the intervention may increase the risk of a negative outcome, is ethically troublesome. In the authors' opinion, the existing evidence from large observational studies and systematic reviews is sufficiently strong to recommend an endometrial preparation strategy that aims to maintain or stimulate the corpus luteum to minimize the risk of HDP and pre-eclampsia after FET cycles.

Mother, father, son and the Italian Law 40/2004. No 'delete' key.

Assisted reproductive technology (ART) has emerged in recent years as a point of significant innovation in the medical field but is also controversial from a bioethical and legal standpoint. In the Italian context, this matter is regulated by Law 40/2004, which specifically requires that informed consent should be obtained from both members of a couple before proceeding with any ART procedure. This consent is deemed irrevocable at the moment of egg fertilization. Recently, a ruling by the Italian Constitutional Court on this matter elicited controversy. The decision permitted embryo transfer even in a case of parental separation, notwithstanding the father's explicit opposition. The Court emphasized the priority of the woman's psychophysical health over the man's, highlighting the traumatic consequences of interrupting the undertaken path. As a result, both the man's right to self-determination regarding the decision to become a father and the need for informed consent at every stage of medical procedures have been downplayed. Moreover, the extensive utilization of procedures like embryo cryopreservation, with associated parental implications, particularly concerning the time frame and the actuality of informed consent, is posing challenges to the initial application framework of Law 40/2004. The objective of this Commentary is to scrutinize and discuss the issues mentioned above.

The impacts of telemedicine on assisted reproduction: a systematic review and meta-analysis.

Telemedicine is being applied in assisted reproduction technology (ART) to provide remote consultations, monitoring and support for patients. This study aimed to evaluate the potential advantages of telemedicine in ART treatment in the form of virtual consultations. Studies in which patients were using telemedicine during ART treatment were identified from four scientific databases (PudMed, EMBASE, Scopus, Web of Science). The success of fertility treatments was compared between telemedicine and in-office care, and patient satisfaction with ART through telemedicine was assessed. Eleven studies, comprising 4697 patients, were identified. Quality assessment (Joanna Briggs Institute Critical Appraisal and revised Cochrane risk-of-bias tools) revealed an acceptable risk of bias for both randomized controlled trials and observational studies. Using a fixed-effects model, telemedicine was comparable to in-person care regarding the pregnancy rate achieved (odds ratio 1.02, 95% confidence intervals 0.83-1.26, P = 0.83). A Q-test suggested that all the included studies were homogeneous. Patients who received telemedicine during fertility treatment reported a high level of satisfaction (91%, 95% confidence intervals 80-96%). Egger's test confirmed that no publication bias was found. Telemedicine could serve as a complementary tool during fertility treatment to facilitate patients' satisfaction and overcome some practical problems without compromising treatment outcomes. Future studies should continue exploring the potential applications of telemedicine in assisted reproduction.

A compact, high-throughput semi-automated embryo vitrification system based on hydrogel.

RESEARCH QUESTION: What is the efficiency and efficacy of the novel Biorocks semi-automated vitrification system, which is based on a hydrogel? DESIGN: This comparative experimental laboratory study used mouse model and human day 6 blastocysts. Mouse oocytes and embryos were quality assessed post-vitrification. RESULTS: The Biorocks system successfully automated the solution exchanges during the vitrification process, achieving a significantly improved throughput of up to 36 embryos/oocytes per hour. Using hydrogel for cryoprotective agent delivery, 12 vessels could be processed simultaneously, fitting comfortably within an assisted reproductive technology (ART) workstation. In tests involving the cryopreservation of oocytes and embryos, the system yielded outcomes equivalent to the manual Cryotop method. For example, the survival rate for mouse oocytes was 98% with the Biorocks vitrification system (n = 46) and 95% for the manual Cryotop method (n = 39), of which 46% and 41%, respectively, progressed to blastocysts on day 5 after IVF. CC-grade day 6 human blastocysts processed with the Biorocks system (n = 39) were associated with a 92% 2 h re-expansion rate, equivalent to the 90% with Cryotop (n = 30). The cooling/warming rates achieved by the Biorocks system were 31,900°C/minute and 24,700°C/minute, respectively. Oocyte quality was comparable or better post-vitrification for Biorocks than Cryotop. CONCLUSIONS: The Biorocks semi-automated vitrification system offers enhanced throughput without compromising the survival and developmental potential of oocytes and embryos. This innovative system may help to increase the efficiency and standardization of vitrification in ART clinics. Further investigations are needed to confirm its efficacy in a broader clinical context.

Vertical transmission of microbiomes into embryo culture media and its association with assisted reproductive outcomes.

RESEARCH QUESTION: Can microbes vertically transmit from semen and follicular fluid to embryo culture media during assisted reproductive technology (ART) treatment? DESIGN: Spent embryo culture media (SECM), seminal fluid and follicular fluid samples were collected from 61 couples with infertility undergoing ART treatment at the Prince of Wales Hospital, Hong Kong SAR, China. Metagenomic analysis was conducted using 16s rRNA sequencing to identify the source of microbes in SECM, correlation between the semen microbiome and male infertility, and correlation between the follicular fluid microbiome and female infertility. RESULTS: Microbial vertical transmission into SECM was reported in 82.5% of cases, and semen was the main source of contamination in conventional IVF cases. The increased abundances of Staphylococcus spp. and Streptococcus anginosus in semen had negative impacts on total motility and sperm count, respectively (P < 0.001). Significant increases in abundance of the genera Prophyromonas, Neisseria and Facklamia were observed in follicular fluid in women with anovulation, uterine factor infertility and unexplained infertility, respectively (P < 0.01). No significant correlation was found between the bacteria identified in all sample types and ART outcomes, including fertilization rate, embryo development, number of available embryos, and clinical pregnancy rate. CONCLUSION: Embryo culture media can be contaminated during ART treatment, not only by seminal microbes but also by follicular fluid and other sources of microbes. Strong correlations were found between specific microbial taxa in semen and sperm quality, and between the follicular fluid microbiome and the aetiology of female infertility. However, no significant association was found between the microbiomes of SECM, semen and follicular fluid and ART outcomes.

ASEBIR Quality Special Interest Group guidance for quality in assisted reproduction technology.

Assisted human reproduction has undergone rapid advances since its inception 45 years ago. To keep pace with these advances, assisted reproduction laboratories should adhere to a quality management system that addresses staffing and training, physical space and air quality, equipment maintenance and other operational matters, and ensures gamete and embryo handling in accordance with the latest quality and safety standards. Accordingly, this review aims to provide a reference document that highlights the critical aspects to consider when establishing and operating an ART laboratory. The review collates and expands upon published national and international guidelines and consensus documents, providing easier access to this large body of important information.