Maternal-Fetal Compatibility in Recurrent Pregnancy Loss.

Nowadays, recurrent pregnancy loss (RPL) is an undesirable condition suffered by many patients of reproductive age. In this scenario, certain immune cell populations and molecules, involved in maternal-fetal compatibility, have emerged as factors related with the pathogenesis of RPL. Among them, uterine Natural Killer cells (uNKs) appear to be of great relevance. These cells are involved in numerous processes during pregnancy, such as the remodeling of uterine spiral arteries or the control of trophoblast invasion. These functions are regulated by the interactions that these cells establish with the extravillous trophoblast, mainly through their Killer Immunoglobulin-like Receptors (KIRs) and the Human Leukocyte Antigen-C (HLA-C) molecules expressed by the embryo. A high level of polymorphism has been reported for both molecules involved in this interaction, with some of the possible KIR-HLA-C combinations being associated with an increased risk of RPL. However, the complexity of the maternal-fetal interface goes beyond this, as other HLA molecules also appear to be related to this reproductive pathology. In this review, we will discuss the role of uNKs in pregnancy, as well as the polymorphisms and clinical implications of KIR-HLA-C binding. We will also address the involvement of other, different HLA molecules in RPL, and the current advice on the appropriate management of patients with 'immunological mismatch', thus covering the main aspects regarding the involvement of maternal-fetal compatibility in RPL.

GnRH agonist trigger in poor prognosis patients undergoing a multicycle approach through DuoStim or consecutive stimulations: a SWOT analysis.

PURPOSE OF REVIEW: Identify the most recent and significant evidence regarding the ovulation trigger within the framework of a multicycle approach through DuoStim, providing valuable insights for improving treatment strategies in patients with a poor prognosis. RECENT FINDINGS: The trigger method plays a pivotal role in optimizing in-vitro fertilization (IVF) stimulation, influencing oocyte retrieval and maturation rates, as well as follicle recruitment in consecutive ovarian stimulations such as double stimulation. Decision-making involves multiple factors and, while guidelines exist for conventional stimulation, specific recommendations for the multicycle approach are not well established. SUMMARY: The different methods for inducing oocyte maturation underscore the need for personalization of IVF protocols. The GnRH agonist trigger induces rapid luteolysis and establishes favorable hormonal conditions that do not adversely affect the recruitment of consecutive follicular waves in the context of DuoStim. It serves as a valid alternative to hCG in freeze-all cycles. This strategy might enhance the safety and flexibility of ovarian stimulations with no impact on oocyte competence and IVF efficacy.

High-impact journal publishing: the devil is in the detail!

Research in medicine is an indispensable tool to advance knowledge and improve patient care. This may be particularly true in the field of human reproduction as it is a relatively new field and treatment options are rapidly evolving. This is of particular importance in an emerging field like "human reproduction", where treatment options evolve fast.The cornerstone of evidence-based knowledge, leading to evidence-based treatment decisions, is randomized controlled trials as they explore the benefits of new treatment approaches. The study design and performance are crucial and, if they are carried out correctly, solid conclusions can be drawn and be implemented in daily clinical routines. The dissemination of new findings throughout the scientific community occurs in the form of publications in scientific journals, and the importance of the journal is reflected in part by the impact factor. The peer review process before publication is fundamental in preventing flaws in the study design. Thus, readers of journals with a high impact factor usually rely on a thorough peer review process and therefore might not question the published data. However, even papers published in high-impact journals might not be free of flaws, so the aim of this paper is to encourage readers to be aware of this fact and critically read scientific papers as 'the devil lies in the details'.

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.

No additional risk of congenital anomalies after first-trimester dydrogesterone use: a systematic review and meta-analysis.

STUDY QUESTION: Is exposure to dydrogesterone a risk factor for congenital anomalies when given in the first trimester for recurrent/threatened pregnancy loss or as luteal support in assisted reproductive technology (ART)? SUMMARY ANSWER: Dydrogesterone, when given in the first trimester for recurrent/threatened pregnancy loss or as luteal support in ART, is not a relevant additional risk factor for congenital anomalies. WHAT IS KNOWN ALREADY: Despite large clinical trials and meta-analyses that show no association between dydrogesterone and congenital anomalies, some recently retracted publications have postulated an association with teratogenicity. Dydrogesterone is also often rated as less safe than bioidentical progestins. STUDY DESIGN SIZE DURATION: A systematic review was conducted according to a pre-specified protocol with searches on Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Clinicaltrials.gov. The search was limited to human studies, with no restrictions on language, geographical region, or date. The search algorithm used a PICO (Population, Intervention, Comparison, Outcome)-style approach combining both simple search terms and medical subject heading terms. As congenital anomalies are mostly reported as secondary outcomes, the search term 'safety' was added. PARTICIPANTS/MATERIALS SETTING METHODS: Interventional study and observational study (OS) designs were eligible for inclusion. Inclusion criteria were: women >17 years old treated for threatened miscarriage, recurrent pregnancy loss, and/or ART; the use of dydrogesterone in the first trimester compared with placebo, no treatment or other interventions; and reporting of congenital anomalies in newborns or infants ≤12 months old (primary outcome). Two authors (A.K., M.R.N.) independently extracted the following data: general study information, study population details, intervention and comparator(s), and frequencies of congenital anomalies (classification, time of determination, and type). Risk of bias focused on the reporting of congenital malformations and was assessed using the Cochrane Risk of Bias Tool Version 2 or the ROBINS-I tool. The GRADEproGDT platform was used to generate the GRADE summary of findings table. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 897 records retrieved during the literature search, 47 were assessed for eligibility. Nine studies were included in the final analysis: six randomized controlled trials (RCTs) and three OSs. Among the RCTs, three had a low risk and three a high risk of bias. Two of the OSs were considered to have a serious risk of bias and one with critical risk of bias and was excluded for the evidence syntheses. The eight remaining studies included a total of 5070 participants and 2680 live births from 16 countries. In the meta-analysis of RCTs only, the overall risk ratio (RR) was 0.92 [95% CI 0.55; 1.55] with low certainty. When the two OSs were included, the overall RR was 1.11 [95% CI 0.73; 1.68] with low certainty. LIMITATIONS REASONS FOR CAUTION: The studies included in the analysis do not report congenital anomalies as the primary outcome; reporting of congenital anomalies was often not standardized. WIDER IMPLICATIONS OF THE FINDINGS: This systematic literature review and meta-analysis provide clear reassurance to both clinicians and patients that dydrogesterone is not associated with congenital anomalies above the rate that might be expected due to environmental and genetic factors. The results of this work represent the highest current level of evidence for the question of congenital anomalies, which removes the existing uncertainty caused by poor quality and retracted studies. STUDY FUNDING/COMPETING INTERESTS: Editorial support was provided by Highfield Communication Consultancy, Oxford, UK, sponsored by Abbott Products Operations AG, Allschwil, Switzerland. A.K., J.A.G.-V., L.P.S., J.N.v.d.A., and J.F.S. received honoraria from Abbott for preparation and participation in an advisory board. J.A.G.-V. received grants and lecture fees from Merck, Organon, Ferring, Gedeon Richter, and Theramex. M.R.N. has no conflicts of interest. J.N.v.d.A. and J.A.G.-V. have no other conflicts of interest. A.K. received payment from Abbott for a talk at the IVF Worldwide congress on 22 September 2023. J.F.S. has received grants from the National Institutes of Health, royalties/licences from Elsevier and Prescient Medicine (SOLVD Health), consulting fees from Burroughs Wellcome Fund (BWF) and Bayer, honoraria from Magee Women's Research Institute, Wisconsin National Primate Research Centre, University of Kansas and Oakridge National Research Laboratory, Agile, Daiichi Sankyo/American Regent, and Bayer, and travel support to attend meetings for the International Academy of Human Reproduction (IAHR). J.F.S. has patents related to diagnosis and treatment of PCOS and prediction of preterm birth. J.F.S. participates on advisory boards for SOLVD Health, Wisconsin National Primate Research Centre, and FHI360, was the past President board member of the Society for Reproductive Investigation, has a leadership role for the following organizations: Scientific Advisory Board, SOLVD Health, EAB Chair for contraceptive technology initiative, FHI360, EAB member, Wisconsin National Primate Research Centre, Advisory Board for MWRI Summit, Chair of BWF NextGen Pregnancy Research Panel, Medical Executive Committee at the Howard, and Georgeanna Jones Foundation, and is Vice President, IAHR. L.P.S. has received consulting fees from Shield Pharmaceuticals, Scynexis, Organon, Natera, Celula China, AiVF, Agile, Daiichi Sankyo, American Regent, and Medicem, honoraria from Agile, Daiichi Sankyo/American Regent, and Bayer, and travel support from BD Diagnostics. L.P.S. participates on the data safety monitoring board for Astellas and is a Chair of DSMB for fezolinetant. Abbott played no role in the funding of the study or in study design, data collection, data analysis, data interpretation, or writing of the report. TRIAL REGISTRATION NUMBER: PROSPERO 2022 CRD42022356977.

Identification of miR-30c-5p microRNA in Serum as a Candidate Biomarker to Diagnose Endometriosis.

The diagnosis of endometriosis by laparoscopy is delayed until advanced stages. In recent years, microRNAs have emerged as novel biomarkers for different diseases. These molecules are small non-coding RNA sequences involved in the regulation of gene expression and can be detected in peripheral blood. Our aim was to identify candidate serum microRNAs associated with endometriosis and their role as minimally invasive biomarkers. Serum samples were obtained from 159 women, of whom 77 were diagnosed with endometriosis by laparoscopy and 82 were healthy women. First, a preliminary study identified 29 differentially expressed microRNAs between the two study groups. Next, nine of the differentially expressed microRNAs in the preliminary analysis were evaluated in a new cohort of 67 women with endometriosis and 72 healthy women. Upon validation by quantitative real-time PCR technique, the circulating level of miR-30c-5p was significantly higher in the endometriosis group compared with the healthy women group. The area under the curve value of miR-30c-5p was 0.8437, demonstrating its diagnostic potential even when serum samples registered an acceptable limit of hemolysis. Dysregulation of this microRNA was associated with molecular pathways related to cancer and neuronal processes. We concluded that miR-30c-5p is a potential minimally invasive biomarker of endometriosis, with higher expression in the group of women with endometriosis diagnosed by laparoscopy.

The adenomyosis/endometriosis IVF patient - call for clinical focus.

Endometriosis and adenomyosis are distinct clinical conditions that carry the same pathophysiological features. In recent years the clinical focus on assisted reproductive technology patients with either condition (E/A) has increased, in the recognition that this subgroup of patients might need special attention to obtain reproductive success. Endometriosis and adenomyosis are characterized by a disruption of progesterone and oestrogen signalling pathways, resulting in local oestrogen dominance and progesterone resistance at the receptor level. Recent scientific evidence suggests that the endometrial progesterone receptor resistance encountered in E/A patients can be overcome by a freeze-all policy, followed by down-regulating circulating oestradiol concentrations prior to frozen embryo transfer (FET), in combination with an increase in exogenous luteal phase progesterone supplementation in hormonal replacement therapy (HRT) FET cycles. Specifically, for adenomyosis patients who do not respond to gonadotrophin-releasing hormone agonist down-regulation in terms of a decrease in circulating oestradiol concentrations, a small case series has suggested that the addition of an aromatase inhibitor for 21 days prior to HRT-FET is a valid option. Endometriosis and adenomyosis are hormonally active diseases, which need to be treated by controlling local hyperoestrogenism and progesterone resistance. Based on physiology and recent preliminary clinical data, the authors of this opinion paper wish to stimulate discussion and spark interest in research in E/A patients.

Progestin-primed ovarian stimulation.

PURPOSE OF REVIEW: The use of progestins as pituitary suppressors has increased progressively, along with more detailed indications for their use, thereby consolidating an alternative approach to the personalization of ovarian stimulation. RECENT FINDINGS: Based on the ability of progesterone to inhibit ovulation, progestins have been used in ovarian stimulation (OS) follicular protocols to prevent a luteinizing hormone surge in patients undergoing in vitro fertilization (IVF), as an alternative to gonadotropin-releasing hormone (GnRH) analogue administration. This review explores the different types of progestogen protocols and their efficacy depending on the type of population or reproductive procedure in which they are administered and in comparison with that of GnRH analogues. Their effect on oocytes and embryos and their safety and cost-effectiveness are also analyzed. SUMMARY: Progestins have proven their effectiveness as a gonadotropin adjuvant in terms of ovarian response, reproductive outcome, and safety. In addition, they offer the convenience of oral administration and a lower cost than GnRH analogues. Whereas oocytes or embryos should be vitrified as it displaces the receptive period with the consequent asynchrony between embryo and endometrium. The evidence endorses progestins as a more friendly approach to OS, especially when frozen-thawed embryo transfer is planned.

An update on the current indications for in vitro maturation.

PURPOSE OF REVIEW: In vitro maturation has become a significant component of modern assisted reproductive techniques. Published data have been supported for the safety and effectiveness of in vitro maturation treatment. In recent years, potential indications for in vitro maturation (IVM) have been a topic of interest and investigation. RECENT FINDINGS: Significant improvements in technique enhancement and data publication for evaluating the efficacy of IVM have been achieved. Recent studies have shown that IVM could offer several advantages over in vitro fertilization. Currently, there are growing indications for IVM beyond the commonly mentioned indication of infertile women with polycystic ovary syndrome. Additionally, some potential candidates might have significant advantages for IVM, such as women diagnosed with gonadotropin resistance ovary syndrome or those seeking fertility preservation. With a better understanding of IVM, from basic science to clinical practice, it can be applied safely, effectively, and affordably to a broader range of patients, making it a more accessible and patient-friendly option. SUMMARY: Despite the possibly acknowledged limitations, the potential of in vitro maturation cannot be denied. As this technique becomes increasingly accessible to patients and more continuous efforts are dedicated to advancing this technique, the impact of in vitro maturation is expected.

Chromosome ends and the theory of marginotomy: implications for reproduction.

Telomeres are the protective structures located at the ends of linear chromosomes. They were first described in the 1930s, but their biology remained unexplored until the early 70s, when Alexey M. Olovnikov, a theoretical biologist, suggested that telomeres cannot be fully copied during DNA replication. He proposed a theory that linked this phenomenon with the limit of cell proliferation capacity and the "duration of life" (theory of marginotomy), and suggested a potential of telomere lenghthening for the prevention of aging (anti-marginotomy). The impact of proliferative telomere shortening on life expectancy was later confirmed. In humans, telomere shortening is counteracted by telomerase, an enzyme that is undetectable in most adult somatic cells, but present in cancer cells and adult and embryonic stem and germ cells. Although telomere length dynamics are different in male and female gametes during gametogenesis, telomere lengths are reset at the blastocyst stage, setting the initial length of the species. The role of the telomere pathway in reproduction has been explored for years, mainly because of increased infertility resulting from delayed childbearing. Short telomere length in ovarian somatic cells is associated to decreased fertility and higher aneuploidy rates in embryos. Consequently, there is a growing interest in telomere lengthening strategies, aimed at improving fertility. It has also been observed that lifestyle factors can affect telomere length and improve fertility outcomes. In this review, we discuss the implications of telomere theory in fertility, especially in oocytes, spermatozoa, and embryos, as well as therapies to enhance reproductive success.

IVF stimulation protocols and outcomes in women with endometriosis.

Endometriosis is a complex medical condition with a high prevalence in women of reproductive age. Fertility is compromised in patients with endometriosis, and success in IVF treatments has been a challenge leading to evaluation of different stimulation protocols. The long-standing debate between GnRH agonist long protocols and short GnRH antagonist protocols is being resolved in favor of the latter, since in addition to presenting equivalent results with respect to the traditional option, they have the additional benefit of safety. The good results derived from vitrification techniques have led to the development of new stimulation strategies, such as progestin-primed ovarian stimulation (PPOS), with a greater degree of approval among patients. None of the stimulation protocols currently applied in women with endometriosis has been shown to be superior, so early intervention with an Assisted Reproduction treatment, regardless of the chosen protocol, can provide these women with good chances of motherhood. Women with endometrioma should be counseled for fertility preservation before planned ovarian endometrioma excision. The number of cryopreserved oocytes or embryos can be increased by repeated cycles.

Endometrial receptivity tests in reproduction: a SWOT analysis.

Endometrial receptivity and its management in assisted reproduction is now a significant focus of research interest. Endometrial receptivity tests, which analyze different panels of gene expression, are usually offered in fertility clinics to determine the women's individual 'window of implantation', providing a personalized timing for embryo transfer. However, there are still no definite indications on whether its inclusion in the study of the infertile couple or the study of patients with repeated implantation failure is essential.

Safety of assisted reproductive techniques in gynecological cancer patients.

PURPOSE OF REVIEW: Gynecological cancer is a very important cause of comorbidity and mortality in women. The current delay in motherhood is increasing the incidence of women under 40 years of age that have not yet achieved their maternity goals when they are diagnosed and standard treatment negatively impacts the reproductive potential of cancer survivors. In this review, we update the information available about the safety of fertility-sparing treatments in young gynecological cancer patients, as well as the safety and efficacy of assisted reproductive techniques (ART) in such group. We also evaluate the long-term gynecological cancer risk in women requiring ART. RECENT FINDINGS: Although eligibility criteria continue to be very strict, there are more and more reports of fertility-sparing approaches outside of what traditionally has been considered safe. Molecular assessment is starting to be used in the selection of appropriate candidates. Data increasingly shows the long term safety and the efficacy of ART and pregnancy in these patients. SUMMARY: Appropriate selection is key to safely preconize fertility-sparing alternatives. Because subfertility may be a result of these procedures, ART could be indicated in this setting. Neither ART nor pregnancy appear to increase recurrences or affect survival rates.

Development and Validation of an Endometriosis Diagnostic Method Based on Serum Biomarkers and Clinical Variables.

Endometriosis affects more than 10% of women of reproductive age, significantly impacting their quality of life. Diagnosis typically takes 4 to 11 years from symptom onset. The gold standard for diagnosing this disease, laparoscopy, is invasive, contributing to this delay in diagnosis. Two studies were conducted to develop a diagnostic test based on the combination of serum biomarkers and clinical variables. Study 1, the development study, aimed to: (i) confirm the ability of CA125, BDNF and clinical variables to differentiate between cases and controls, and (ii) develop a diagnostic algorithm based on these results. Study 2 validated the clinical performance of the developed in vitro diagnostic (IVD) test in diagnosing endometriosis. Serum samples and clinical variables extracted from psychometric questionnaires were obtained from the Oxford Endometriosis CaRe Centre biobank (UK). Case/control classification was performed based on laparoscopy and histological verification of the excised lesions. Studies 1 and 2 included n = 204 and n = 79 patients, respectively. Study 1 found a statistically significant difference between cases and controls for levels of both biomarkers. Of the assessed clinical variables from the patients' medical histories, six were found to be significantly different between endometriosis cases and controls. CA125, BDNF and these six clinical variables were combined into a multivariable prediction model. In Study 2, the IVD test demonstrated sensitivity and specificity values of 46.2% (25.5-66.8%) and 100% (86.7-100%), respectively. Due to its high specificity, this IVD test is a simple and accurate rule-in test for early disease identification, even in the presence of non-specific symptoms.

A Randomized Controlled Intervention Trial with Danazol to Improve Telomeric and Fertility Parameters in Women with Diminished Ovarian Reserve: A Pilot Study.

Background: Most women who are treated at in vitro fertilization (IVF) clinics have trouble conceiving due to ovarian failure (OF), which seems to be associated to short telomeres and reduced or absent telomerase activity in their granulosa cells. Indeed, telomere pathways are involved in organ dysfunction. However, sexual steroids can stimulate the expression of the telomerase gene and have been successfully used to prevent telomere attrition. Thus, a strategy to improve IVF outcomes in women with OF could be telomerase reactivation using sexual steroids. Methods: We conducted a double-blind, placebo-controlled study. Patients with diminished ovarian reserve were randomized to Danazol or placebo for 3 months. We included patients with normal ovarian reserve in the study as untreated controls. Patients and controls underwent several ovarian stimulations (OSs). Telomere and IVF parameters were assessed. Results: We found that the mean telomere length in blood and the percentage of short and long telomeres were similar throughout the 3 months of treatment with Danazol. Remarkably, while the number of cells with one telomeric repeat-containing RNA (TERRA) focus decreased (p = 0.04) after the first month of Danazol treatment, the number of cells with 2 to 4 TERRA foci increased (p = 0.02). Regarding fertility, no differences were found in the antral follicle count. Interestingly, in OS performed after the trial, all Danazol-treated patients had a better MII oocyte rate compared to OS performed before the pilot study.EudraCT number: 2018-004400-19. Conclusions: Danazol treatment seemed to affect telomere maintenance, since both the number of TERRA foci and the ratio of MII oocytes changed. However, further research is needed to confirm these results.

Preimplantation genetic testing for aneuploidy is not related to adverse obstetric and neonatal outcomes in singleton pregnancies.

STUDY QUESTION: What is the potential impact of preimplantation genetic testing for aneuploidy (PGT-A) on obstetric and neonatal outcomes? SUMMARY ANSWER: PGT-A is not associated with increased rates of adverse maternal and neonatal outcomes in singleton pregnancies following IVF/ICSI cycles. WHAT IS KNOWN ALREADY: PGT-A pregnancies may be associated with increased risks of lower birthweight, preterm delivery, and hypertensive disorders compared with natural pregnancies. In a recent meta-analysis, the overall obstetric and neonatal outcomes of PGT-A pregnancies were favorable compared with those of IVF/ICSI pregnancies, although PGT-A pregnancies were associated with a higher risk of hypertensive disorders. STUDY DESIGN, SIZE, DURATION: A multicenter retrospective cohort study was performed in University-affiliated infertility centers. Single live births following IVF/ICSI between October 2016 and January 2021 were included in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 7146 live births after single embryo transfers with (n = 3296) or without (n = 3850) PGT-A were included. The primary outcome was pre-eclampsia and secondary outcomes included gestational diabetes, low birthweight and very low birthweight, cesarean section delivery, emergency cesarean section, as well as preterm birth, birthweight, congenital abnormalities, neonatal sex, Apgar score at 5 min, and neonatal intensive care unit admission. In a subgroup analysis, were included only blastocysts screened with next-generation sequencing (NGS). MAIN RESULTS AND THE ROLE OF CHANCE: Univariate analysis showed that pre-eclampsia, cesarean section incidence, and low Apgar score were higher in women undergoing PGT-A. However, after performing multivariate logistic and linear regression models accounting for many possible confounders, pregnancies that had been conceived after embryo biopsy showed no increase in adverse obstetric and neonatal outcomes. The subgroup analysis including patients with blastocysts screened by NGS showed a decreased risk of preterm birth in the group undergoing PGT-A. LIMITATIONS, REASONS FOR CAUTION: Caution should be used when interpreting the data because of its limitations, mainly related to its retrospective design. Although this is a large multicenter study, data acquisition included self-reporting questionnaires, and the deliveries occurred in different institutions with distinct protocols. WIDER IMPLICATIONS OF THE FINDINGS: The current study does not show any major adverse clinical outcomes after PGT-A. Efforts should be made to promote good quality research on embryo biopsy in terms of neonatal and obstetric outcomes, as well as its long-term consequences. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was obtained for this study. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.