Women with advanced maternal age (AMA) face a significant decline in embryo euploidy rates, leading to reduced fertility and increased risks of adverse pregnancy outcomes. While preimplantation genetic testing for aneuploidy (PGT-A) aids in selecting euploid embryos, it does not address the underlying causes of aneuploidy. Growth hormone (GH) has shown promise in improving oocyte quality and embryo development, but its impact on the euploidy status of embryos remains underexplored. This randomized controlled trial aims to evaluate the effect of GH supplementation on the euploidy rate of blastocysts in AMA patients. A total of 400 women with AMA undergoing PGT-A will be randomized into two groups: the GH group (GnRH antagonist protocol with daily subcutaneous injection of 2 IU GH starting from the previous menstrual cycle) and the control group (GnRH antagonist protocol without GH). Embryos will be cultured in time-lapse monitoring (TLM), and morphokinetic parameters will be recorded. Trophectoderm biopsies will be analyzed using next-generation sequencing-based PGT-A to determine ploidy status. The primary outcome is the euploidy rate of blastocysts, while secondary outcomes include embryo developmental and morphokinetic parameters, as well as pregnancy outcomes after transfer. This prospective, single-center RCT will investigate the impact of GH supplementation on euploidy rates, morphokinetic parameters, and transfer outcomes in AMA patients. By combining PGT-A and TLM with randomization and blinding, the study will minimize bias and provide robust insights into how GH may improve reproductive outcomes in AMA women, offering high-quality clinical evidence for ART practice. NCT05447208, www.clinicaltrials.gov. Registered on July 3rd, 2022.

The interaction between sperm and the zona pellucida (ZP), which involves the binding of sperm surface ligands to complementary carbohydrates on the ZP, is the initial direct contact between gametes and is crucial for subsequent gamete fusion and successful mammalian fertilization. In this study, we show that Garin3 is a critical gene for sperm-oocyte ZP binding. Garin3 expression begins during the acrosomal stage of spermatogenesis, and the gene is highly expressed in the male reproductive system. We created a Garin3 gene-knockout mouse model, and spermatozoa lacking Garin3 exhibited only mild morphological changes and showed no deficiency in motility; however, their ability to bind to the oocyte ZP was severely impaired and this ultimately resulted in failure of in vitro fertilization. These findings suggest that Garin3 is not directly involved in sperm-ZP binding and that it instead indirectly affects such binding by regulating the expression and localization of acrosome-related proteins, including RAB2, SPACA1, ADAM2, and ACR. Notably, fertilization failure was effectively rescued by bypassing the ZP-binding step by removing the ZP altogether or by performing intracytoplasmic sperm injection (ICSI). In human sperm samples, the expression levels of GARIN3 were significantly reduced in sperm with poor fertilization potential compared to sperm with normal fertilization potential, and this was consistent with the phenotypic observations in animal models. Our findings highlight the crucial role of Garin3 in fertilization and the potential molecular mechanism behind its effects.

OBJECTIVE:To test the hypothesis that women assigned to a natural ovulation regimen before frozen embryo transfer compared with a programmed regimen would have an increased chance of a healthy live birth and a reduced risk of pre-eclampsia or eclampsia. DESIGN:Multicentre, randomised, parallel group, assessor blinded clinical trial. SETTING:24 academic fertility centres in China. PARTICIPANTS:4376 ovulatory women (aged 20-40 years) planning to undergo a frozen single blastocyst transfer. INTERVENTIONS:Eligible participants were randomised (1:1) to receive a natural ovulation regimen or a programmed regimen of hormone replacement for endometrial preparation. Endometrial preparation and frozen embryo transfer timing were determined in the natural ovulation regimen group by monitoring natural follicle development and measuring serum levels of luteinising hormone, oestradiol, and progesterone. In the programmed regimen group, endometrial preparation was achieved by sequential administration of oestrogen and progesterone. MAIN OUTCOMES AND MEASURES:Primary outcomes were a healthy live birth and pre-eclampsia or eclampsia after a frozen embryo transfer. Secondary outcomes were cycle cancellation, biochemical pregnancy, clinical pregnancy, ongoing pregnancy, pregnancy loss, ectopic pregnancy, live birth, birth weight, and maternal, fetal, and neonatal complications. RESULTS:In the intention-to-treat analyses, 910 (41.6%) of 2185 patients in the natural ovulation regimen group and 890 (40.6%) of 2191 in the programmed regimen group achieved a healthy live birth (relative ratio 1.03 (95% confidence interval (CI) 0.96 to 1.10); P=0.49). The risk of pre-eclampsia was lower in the natural ovulation regimen group among patients who achieved clinical pregnancy than in the programmed regimen group (2.9% (38 of 1302) v 4.6% (61 of 1326); 0.63 (0.43 to 0.94); P=0.02). The incidences of early pregnancy loss (12.1% (158 of 1302) v 15.2% (201 of 1326); 0.80 (0.66 to 0.97)), placental accreta spectrum (1.8% (24 of 1302) v 3.6% (48 of 1326); 0.51 (0.31 to 0.83)), caesarean section (69.5% (776 of 1117) v 75.6% (831 of 1100); 0.92 (0.87 to 0.97)), and postpartum haemorrhage (2.0% (22 of 1117) v 6.1% (67 of 1100); 0.32 (0.20 to 0.52)) were lower in the natural ovulation regimen group. No differences between groups were observed for birth weight or neonatal complications. The rate of cycle cancellation was higher in the natural ovulation regimen (16.2% (354 of 2185) v 11.5% (251 of 2191), P<0.001). The prespecified per protocol and subgroup analyses yielded results consistent with the intention-to-treat analyses. CONCLUSIONS:In ovulatory women, a natural ovulation regimen for endometrial preparation was as effective as programmed regimen in terms of achieving a healthy live birth after frozen embryo transfer, but with a lower risk of maternal complications during pregnancy. TRIAL REGISTRATION:Chinese Clinical Trial Registry ChiCTR2200057990.

IMPORTANCE:Management of low responders is a challenge in the field of assisted reproduction. Several trials comparing frozen versus fresh embryo transfer have been published and are restricted mainly to high and normal responders. Current studies on the suitability of frozen embryo transfer in low responders are limited and yielded mixed results. OBJECTIVE:To investigate whether cryopreservation of all embryos and subsequent frozen embryo transfer produces better reproductive outcomes compared with fresh embryo transfer in low responders. EVIDENCE REVIEW:We searched PubMed, Embase, Cochrane Library, Web of Science Core Collection and Scopus databases from inception to December 2025. After de-duplication, titles and abstracts of 4,423 articles were screened, and 154 full-text articles were assessed for eligibility. One randomized controlled trial and 14 nonrandomized studies were included in the systematic review. Data extraction was performed for the primary outcome of live birth rate and secondary outcomes. FINDINGS:High certainty evidence from 1 randomized controlled trial showed that frozen embryo transfer resulted in a reduction in live birth (risk ratio [RR], 0.79; 95% confidence interval [CI], 0.65-0.94), clinical pregnancy (RR, 0.83; 95% CI, 0.71-0.97) and cumulative live birth rate (RR, 0.86; 95% CI, 0.75-0.99), whereas nonrandomized studies provided very uncertain evidence that there was no significant difference in the 2 groups including live birth rate (RR, 1.00; 95% CI, 0.65-1.55). A lower miscarriage rate favoring fresh embryo transfer was found in women fulfilling the Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number criteria (RR, 1.31; 95% CI, 1.11-1.56). Consistent evidence indicated that frozen embryo transfer did not produce significant improvements in other reproductive outcomes. CONCLUSION AND RELEVANCE:Our results suggested that the "freeze-all" strategy did not produce better reproductive outcomes compared with fresh embryo transfer in low responders. Reproductive outcomes may be improved by performing fresh embryo transfer, which could be explained by a more physiological endometrium or better embryo quality without injury caused by cryopreservation. These findings should be further explored in randomized trials. TRIAL REGISTRATION:The review protocol was registered at PROSPERO (trial registration number: CRD420251138047, URL: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251138047). Date of registration: 9 September 2025.

Recurrent implantation failure (RIF) remains a major challenge in assisted reproductive technology, and the molecular mechanisms underlying endometrial receptivity are incompletely understood. This study aimed to comprehensively characterize transcriptomic alterations, including alternative splicing events (ASEs), differential gene expression (DEGs), and immune cell dynamics across different phases of endometrial receptivity in women with RIF. Endometrial biopsies were collected from 90 healthy fertile controls and 73 RIF patients during pre-receptive, receptive, and post-receptive phases. High-throughput RNA sequencing was performed, and bioinformatic analyses were conducted to identify ASEs, DEGs, immune cell composition, and RNA-binding protein (RBP) networks. Skipped exons and mutually exclusive exons were the predominant splicing events observed. Both ASEs and DEGs were significantly enriched in pathways regulating cell adhesion, cytoskeletal organization, and immune modulation. KHDRBS3 emerged as a potential key RBP involved in splicing regulation during the window of implantation. Immune profiling revealed dynamic alterations in CD8 + T cells, NK cells, and monocytes between non-receptive and receptive phases, suggesting immune dysregulation associated with implantation failure. Drug repurposing analysis identified several small molecules targeting ASE-related genes, offering promising therapeutic options for RIF. These findings highlight the coordinated changes in alternative splicing, gene expression, and immune cell composition that characterize endometrial receptivity and provide insights that may guide the development of novel diagnostic biomarkers and targeted interventions to improve reproductive outcomes.

PURPOSE:To describe a rare case of a normal fertile male with the specific tissue distribution of 46,XX in the peripheral blood and gonadal chimerism confirmed by the novel next-generation sequencing (NGS) methodology. METHODS:Cytogenetic analyses, low-pass copy number variation sequencing (CNV-seq) and NGS-based short tandem repeat (STR) tests. RESULTS:Routine peripheral blood karyotyping showed 46,XX. Fluorescence in situ hybridization (FISH) analysis of lymphocyte metaphase nuclei confirmed 46,XX and sex-determine region Y (SRY)-negative. Further CNV-seq revealed the presence of Y chromosome in the semen. NGS-based STR tests discovered low-level Y chromosome in the buccal mucosa and three alleles in the semen, suggesting that this chimerism is likely the outcome of a parthenogenetically activated oocyte fertilized by a Y and X sperm. The patient underwent intracytoplasmic sperm injection (ICSI) and resulted in a normal singleton pregnancy. CONCLUSION:Individuals with 46,XX/46,XY chimerism in the gonad can display normal phenotype and fertility. NGS has proved to be a promising alternative to conventional chimerism assays.

To identify the disease-causing gene behind infertile couples with female infertility and abnormal fertilization. Whole-exome sequencing and Sanger sequencing were used to identify variants in disease-causing genes in 119 infertile couples with abnormal fertilization. Molecular modeling and functional analysis were used to evaluate the pathogenic effects of the variants. We identified one homozygous ASTL variant and three homozygous WEE2 variants from four affected individuals. Among them, WEE2 variants c.1006-1007insTA (p.His337Tyrfs*24) and c.585G > C (p.Lys195Asn) have been previously reported. Structural modeling indicated that the novel ASTL variant c.643G > A (p.Glu215Lys) disrupted the hydrogen bond with Gly-213, while the novel WEE2 variant c.791C > T (p.Ala264Val) significantly decreased tyrosine 15 phosphorylation on Cdc2 and reduced pronucleus formation rate in vitro. In addition, intracytoplasmic sperm injection with assisted oocyte activation (ICSI-AOA) can prevent polyspermy in oocytes with ASTL c.643G > A (p.Glu215Lys) variant and can assist patients in delivering a girl. We identified novel homozygous variants in ASTL and WEE2, and functional analysis confirmed the pathogenicity of these variants. In addition, ICSI-AOA rescued the polyspermy phenotype in patients with ASTL c.643G > A (p.Glu215Lys) variant. Our findings further reveal the important role of ASTL and WEE2 in female reproduction and expand the mutational spectrum of the abnormal fertilization related genes ASTL and WEE2.

STUDY QUESTION:Can new genetic factors responsible for oocyte defects be identified in infertile women, especially for those with spindle assembly defects? SUMMARY ANSWER:We identified homozygous and compound heterozygous variants of DLGAP5 in three infertile individuals from two independent families. WHAT IS KNOWN ALREADY:Some genes have been found to be responsible for female infertility with oocyte maturation defects. During mitosis, DLGAP5 is involved in promoting microtubule polymerization and spindle formation. STUDY DESIGN, SIZE, DURATION:The DLGAP5 variants were identified by whole-exome sequencing in a cohort of 3627 female infertility patients diagnosed with oocyte maturation defects or embryonic development problems, and all participants were recruited from 2015 to 2023. Thirty-six hours after cell transfection, the expression levels of wild-type (WT) and mutant DLGAP5 were evaluated by western blot (n = 3 biological replicates). Human germinal vesicle (GV) oocytes retrieved from assisted reproductive procedure were introduced for cRNA (n = 3-5 oocytes per group) and antibody injection (n = 10-15 oocytes per group). Knock-in (KI) mouse model was generated by CRISPR-Cas9 and genotyping was performed at postnatal Days 10-15. Sexually mature females (6-10 weeks old) were used for fertility test (n = 6 mice per group, lasts 6-8 months), western blot (n = 3 biological replicates), IVF (n = 3 biological replicates), embryos collection (n = 3 biological replicates), immunofluorescence (n = 3 biological replicates), RNA-sequencing (RNA-seq, n = 3 biological replicates), and other functional assays between 2019 and 2023. PARTICIPANTS/MATERIALS, SETTING, METHODS:The DLGAP5 variants were identified by whole-exome sequencing and further confirmed by Sanger sequencing. Western blot was used to detect the expression of mutant DLGAP5 in HEK-293T cells after transfection. cRNA injection and immunofluorescence were performed to view the location of DLGAP5 in human oocytes. Knockdown of DLGAP5 by Trim-Away in human oocytes was conducted to observe the effect of DLGAP5 on spindle assembly and oocyte maturation. Then, Dlgap5 KI mice were constructed to mimic the phenotype of the affected individuals. After phenotypic assessment, western blot, IVF, assessment of embryonic development, chromosome counting, RNA-seq, and quantitative real-time PCR were performed to elucidate the pathological mechanism of DLGAP5 variants. MAIN RESULTS AND THE ROLE OF CHANCE:We identified homozygous nonsense DLGAP5 variant (NM_014750.5, c.431delA (p.Lys144Argfs*55)) in two affected sisters from family 1 and compound heterozygous variants (c.C847G (p.Pro283Ala) and c. C1202G (p.Thr401Ser)) in one infertile individual in family 2. p. Lys144Argfs*55 led to protein degradation (P < 0.0001) and p. Pro283Ala resulted in a significant decrease in protein level (P = 0.0021). DLGAP5 was located on the spindle and mutant did not alter its location. Knockdown of DLGAP5 in human oocytes impaired spindle assembly and led to oocyte maturation arrest (P = 0.0055). Homozygous (HO) Dlgap5 KI female mice showed reduced fertility (P < 0.0001) due to embryonic arrest at the 4-cell stage (P < 0.0001) and a low blastocyst formation rate (P < 0.0001). RNA-seq data of 4-cell embryos showed that differentially expressed genes (DEGs) were involved in cell cycle regulation, checkpoint control, and TGF-β signaling pathways, which may account for the embryonic development arrest. LARGE SCALE DATA:N/A. LIMITATIONS, REASONS FOR CAUTION:Due to phenotypic differences between different DLGAP5 variants, more cases are needed to expand our understanding of the function of DLGAP5 in female infertility. Although RNA-seq data have shown the potential impact of DLGAP5 on cell cycle, embryonic development, and regulation of TGF-β signaling, more experiments are still requested to demonstrate the more direct role of DLGAP5 in oocyte and embryonic development. WIDER IMPLICATIONS OF THE FINDINGS:Our findings elucidated the role of DLGAP5 in human oocyte spindle assembly and the effects of the corresponding variants in the pathogenesis of oocyte maturation arrest, and these findings suggest that DLGAP5 is a novel maker for genetic counseling. STUDY FUNDING/COMPETING INTEREST(S):This work was supported by the National Key Research and Development Program of China (2024YFC2706600), the National Natural Science Foundation of China (82325021, 82288102, 32130029, 82371662, 82171643, 82201767, 82422033), the National Key Research and Development Program of China (2022YFC2702300), the New Cornerstone Science Foundation through the XPLORER PRIZE, L.W. is a SANS Exploration Scholar, and the Fund of Fudan University and Cao'ejiang Basic Research (24FCB01). None of the authors declare any conflict of interest. TRIAL REGISTRATION NUMBER:N/A.

How to optimize haplotype construction in complex PGT-M scenarios without proband samples and with anticipated difficulties in identifying an embryo carrier as proband (EAP)? Leveraging gametes and arrested embryos offers a personalized, cost-effective approach for haplotyping in challenging PGT-M cases, meanwhile minimizing additional invasive procedures for patients or embryos. The clinical practice of PGT-M typically employs a double-check strategy that includes mutation detection via Sanger sequencing and haplotype construction using proband DNA. This approach ensures accuracy by mitigating the risks of allele dropout and recombination. In cases where a proband sample is unavailable or identifying an EAP is challenging, alternative references like single sperm or polar body can fulfill this role. However, challenges intensify in cases of gonadal mosaicism, diminished ovarian reserve (DOR), or X-linked diseases with sex chromosomal abnormalities, as identifying the disease-associated haplotype in embryos may prove difficult. This prospective single-center study enrolled five families undergoing preimplantation genetic testing for monogenic disorders (PGT-M) from January to December 2023, specifically targeting cases with (1) diagnosed or suspected gonadal mosaicism, (2) DOR, or (3) X-linked variants associated with a 47,XXX or 47, XXY karyotype. Various methodologies were utilized to identify the suitable proband and construct risk parental haplotypes, with PGT findings clinically validated through amniocentesis. Targeted deep sequencing was employed to identify mosaicism in suspected cases of gonadal mosaicism. In addition to standard PGT, single sperm (for male carriers), arrested oocytes (for female carriers), and arrested embryos were collected for potential proband identification. Linkage analyses were performed to reduce allele dropout based on SNPs of variant-carrying gametes or embryos, with a preference for testing gametes or hemizygotes in cases of X-linked variants with abnormal karyotypes. A total of 11 stimulation cycles were conducted in the five cases, resulting in the production of 26 blastocysts. Additionally, ten single sperms, four arrested eggs and 21 arrested embryos were collected and analyzed. Direct sequencing was performed to identify carriers for suitable proband selection. Specifically, a single sperm and an arrested oocyte were designated as probands for the two cases with gonadal mosaicism, while an arrested embryo served as the proband for a case of DOR. For the two cases involving X-linked variants with a 47,XXX karyotype, two hemizygous arrested embryos were utilized as probands separately. Based on the PGT-M results and chromosomal ploidy assessments, five blastocysts were transferred, resulting in four healthy live births. The genetic status of these births was confirmed through amniocentesis. This study proposed a novel comprehensive workflow for PGT-M to address challenges in haplotyping, enhancing the efficacy of genetic screening in assisted reproductive technologies. The findings are derived from a relatively small sample size, which may not comprehensively reflect the diverse range of clinical situations we are likely to encounter. This research introduces a cost-effective workflow for precise embryo genotyping in complex PGT-M scenarios without proband samples. It takes gonadal mosaicism, the ovarian reserve, and sexual chromosome karyotypes into account, meanwhile minimizes invasive procedures. Larger cohort studies are crucial for validating and enhancing the methodology’s applicability across diverse clinical settings. Yes

Oocyte/embryo defects can result in oocyte maturation arrest, fertilization failure, embryonic arrest, and infertility as well as recurrent in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) failures. However, the genetic determinants of human oocyte/embryo defects remain largely unknown, and the overall genetic diagnostic yield for such defects has not been evaluated. Here, we performed exome sequencing in 3,627 patients with oocyte/embryo defects. We identified a total of 479 positive cases carrying variants in 37 known genes, indicating a diagnostic yield of 13.2%. Case-control association studies combined with gene set enrichment analysis identified 123 novel candidate genes responsible for oocyte/embryo defects. These results provide a comprehensive genetic landscape of human oocyte/embryo defects and highlight the clinical significance of genetic counseling in infertile patients with oocyte/embryo defects. Our study will lay the foundation for transforming the traditional clinical practice for failed IVF/ICSI attempts into genetic-based precision and personalized treatment for these patients.

The microtubule organizing centers (MTOCs) of human and mouse oocytes are essential for meiotic spindle assembly and for ensuring precise chromosome segregations. Previous studies mainly focus on investigating MTOCs changes in metaphase I oocyte. However, the detailed dynamic changes and underlying mechanisms of the MTOCs in germinal vesicle (GV) oocytes-a stage that early events of MTOC maturation happened- remain unclear. Here we explored the dynamics of MTOCs maturation in human and mouse GV oocytes and found that MTOCs maturation is a largely conserved process, consisting of two tightly coupled processes referred to as MTOCs activation and migration. We found that cytoskeleton associated protein 5 (CKAP5) and transforming acidic coiled-coil containing protein 3 (TACC3) play key roles in MTOCs maturation in oocytes. The activation of the MTOCs is a prerequisite for migration initiation, and the migration of the MTOCs is facilitated by dynein/dynactin in oocytes. The disruption of MTOC maturation resulted in spindle assembly failure. Importantly, impaired MTOCs maturation is associated with the physiological aging of oocytes. This study provides a comprehensive understanding of MTOCs dynamics in human and mouse oocytes.

To compare the euploidy rate between the progestin-primed ovarian stimulation (PPOS) and gonadotrophin-releasing hormone (GnRH) antagonist protocols in preimplantation genetic testing for aneuploidy (PGT-A). The euploidy rate of blastocysts per patient is comparable for patients using PPOS and GnRH antagonist protocols. Progestin can inhibit the pituitary luteinising hormone (LH) surge during ovarian stimulation for in vitro fertilisation (IVF). Studies show PPOS is effective in blocking the LH surge in IVF. More and more centers are using PPOS because this regimen appears simpler and more economical. A few studies showed that the PPOS and GnRH antagonist protocols result in comparable outcomes, including the number of mature oocytes, blastocyst formation rate, euploidy rate of blastocysts, clinical pregnancy rate, and live birth rate. But some studies demonstrated contradictory results. This is a randomized controlled trial of 400 women recruited between June 2020 and August 2024. The primary outcome is the euploidy rate of blastocysts. Women aged <43 years undergoing PGT-A cycles were randomized to either PPOS group (n = 200) or GnRH antagonist group (n = 200). PGT-A was indicated for advanced maternal age (≥38 years), recurrent pregnancy loss (≥2 consecutive pregnancy loss) and repeated implantation failure (≥4 embryos or ≥ 2 blastocysts replaced without success) or foetal aneuploidy in previous pregnancies. PGT-A was performed according to next-generation sequencing technology. Serum estradiol level on the triggering day in the PPOS group was significantly higher than those in GnRH antagonist group (3529.5 (2347.8-5523.3)pg/ml versus 3145 (2217.8-4610.3)pg/ml, respectively, P = 0.04). Total gonadotrophin dose used in PPOS group was significantly lower in the PPOS group than the GnRH antagonist group (2400 (1668.8-3150)IU versus 2700 (2100-3300)IU, respectively, P = 0.03). The two groups were similar in other demographic characteristics and the numbers of oocytes obtained or fertilized, cleaving embryos, blastocysts developed. No statistically significant difference was observed in the euploidy rate of blastocysts between the PPOS and GnRH antagonist groups (44.4 (23.8-66.7) % versus (50.0 (28.6-75.0) %, P = 0.25). The number of euploid blastocysts per patient was similar for the PPOS and GnRH antagonist groups (1 (1-2) versus 1 (1-2.5), P = 0.47). 136 women in the PPOS group and 152 women in the GnRH antagonist group had their first frozen embryo transfer after PGT-A. Both groups showed comparable clinical pregnancy, ongoing pregnancy, miscarriage, ectopic pregnancy, and live birth rate of the first frozen embryo transfer. At the time of abstract submission, 2 women are in the ongoing pregnancy stage and are waiting for the delivery outcomes. We expect to have completed results by the time of the conference. The researchers and the participants cannot be blinded to treatment allocation. The findings of the study support the use of PPOS for patients undergoing preimplantation genetic testing, oocyte donation, fertility preservation, and for patients undergoing a freeze-all cycle. Yes

Mitochondria play diverse roles in mammalian physiology. The architecture, activity, and physiological functions of mitochondria in oocytes are largely different from those in somatic cells, but the mitochondrial proteins related to oocyte quality and reproductive longevity remain largely unknown. Here, using whole-exome sequencing data from 1,024 women (characterized by oocyte maturation arrest and degenerated or morphologically abnormal oocytes) and 2,868 healthy controls, we performed a population and gene-based burden test for mitochondrial genes and identified a candidate gene, cytochrome c oxidase assembly protein 15 (COX15). We report that biallelic COX15 pathogenic variants cause human oocyte ferroptosis and female infertility in a recessive inheritance pattern. COX15 variants impaired mitochondrial respiration in Saccharomyces cerevisiae and led to reduced protein levels in HeLa cells. Oocyte-specific deletion of Cox15 led to impaired Fe2+ and reactive oxygen species homeostasis that caused mitochondrial dysfunction and ultimately sensitized oocytes to ferroptosis. In addition, ferrostatin-1 (an inhibitor of ferroptosis) could rescue the oocyte ferroptosis phenotype in vitro and ex vivo. Our findings not only provide a genetic diagnostic marker for oocyte development defects but also expand the spectrum of mitochondrial disorders to female infertility and contribute to unique insights into the role of ferroptosis in human oocyte defects.

Spindle bipolarization, the process of a microtubule mass transforming into a bipolar spindle, is a prerequisite for accurate chromosome segregation. In contrast to mitotic cells, the process and mechanism of spindle bipolarization in human oocytes remains unclear. Using high-resolution imaging in more than 1800 human oocytes, we revealed a typical state of multipolar intermediates that form during spindle bipolarization and elucidated the mechanism underlying this process. We found that the minor poles formed in multiple kinetochore clusters contribute to the generation of multipolar intermediates. We further determined the essential roles of HAUS6, KIF11, and KIF18A in spindle bipolarization and identified mutations in these genes in infertile patients characterized by oocyte or embryo defects. These results provide insights into the physiological and pathological mechanisms of spindle bipolarization in human oocytes.

Background Genetic mosaicism is commonly observed in human blastocysts. Embryos’ morphokinetic feature observed from time-lapse monitoring (TLM) is helpful to predict the embryos’ ploidy status in a non-invasive way. However, morphokinetic research on mosaic embryos is extremely limited. Moreover, transfer of mosaic embryos is a new attempt in reproductive medicine, while studies regarding the clinical and neonatal outcomes following transfer of embryos with different levels and types of mosaicism are needed. This study aimed to investigate the morphokinetic characteristics of mosaic blastocysts, uncover clinical outcomes of mosaic embryos, and evaluate the effect of level and type of mosaicism on transfer outcomes. Results A total of 923 blastocysts from 229 preimplantation genetic testing cycles were cultured in TLM incubators in a single fertilization center between July 2016 and July 2021. Multivariate logistic regression models showed mosaic embryos had significantly shorter time to reach morula when compared with euploid ( P = 0.002), mosaic with aneuploid ( P = 0.005), and aneuploid ( P = 0.005) embryos after adjusting the potential confounders. KIDScore is an artificial intelligence scoring program from time lapse incubation system to predict embryo implantation potential. Mosaic with aneuploid embryos had significantly lower KIDScore than euploid ( P = 6.47e −4 ), mosaic ( P = 0.005), and aneuploid ( P = 0.004) embryos after adjustment. Meanwhile, we compared the clinical outcomes following transfer of low-level (< 50%) mosaic embryos ( N = 60) with euploid embryos ( N = 1301) matched using propensity scoring collected from September 2020 to January 2023. Mosaic embryos had significantly lower clinical pregnancy rate (41.67% vs. 57.65%, P = 0.015) and live birth rate (38.33% vs. 51.35%, P = 0.048) than the euploid embryos. Subgroup analyses showed the whole, segmental, and complex chromosome mosaic embryos had the similar clinical outcomes. Conclusions The shortened time to reach morula in mosaic embryos and the low KIDScore in mosaic with aneuploid embryos revealed innovative clues to embryo selection with the non-invasive TLM and provided new insights into biological mechanism of chromosomal abnormality. The analyses of overall and subgroups of mosaic embryo transfer outcomes helped to optimize embryo transfer scheme for in-vitro fertilization procedures. Multi-center prospective studies with large sample sizes are warranted to validate our results in the future.

Endometrial polyps commonly contribute to female infertility, and hysteroscopic resection is the established surgical approach for their treatment. Numerous resection methods are available, with the most used and cost-effective options being cold resection employing micro-scissors or hot resection using an electric loop. However, both methods involve sharp resection, posing a challenge in achieving complete polyp removal while avoiding damage to the uterine endometrium. To address this issue, this study proposes an innovative approach: the combined use of the 6 Fr micro- scissors and forceps under hysteroscopy. The method entails utilizing 6 Fr micro- scissors to initially remove large polyps, followed by using 6 Fr micro-forceps to extract the remaining polyp tissue expeditiously and bluntly near the basal layer of the endometrium. This approach not only prevents surgical damage to the basal layer of the endometrium but also mitigates the risk of residual polyps resulting from incomplete resection. This method is particularly suitable for women with fertility requirements, offering additional considerations for the selection of treatment options for endometrial polyp resection.

To explore the effects of parental sex chromosome abnormality on their preimplantation embryos. This is a retrospective cohort study including 83 couples with sex chromosome abnormalities undergoing preimplantation genetic testing (PGT) between 2013 to 2023. The preimplantation genetic testing results and pregnancy outcomes were compared to those of a control group consisting of 166 age-matched couples with normal karyotypes who underwent preimplantation genetic testing for monogenic disorders (PGT-M). Student’s t-tests, chi-square or Fisher’s exact tests were applied to compare clinical characteristics. The embryo euploidy rate was lower (58.94

Preimplantation embryonic arrest is an important pathogenesis of female infertility, but little is known about the genetic factors behind this phenotype. MEI4 is an essential protein for DNA double-strand break formation during meiosis, and Mei4 knock-out female mice are viable but sterile, indicating that MEI4 plays a crucial role in reproduction. To date, MEI4 has not been found to be associated with any human reproductive diseases. Here, we identified six compound heterozygous and homozygous MEI4 variants—namely, c.293C > T (p.Ser98Leu), c.401C > G (p.Pro134Arg), c.391C > G (p.Pro131Ala), c.914A > T (p.Tyr305Phe), c.908C > G (p.Ala303Gly), and c.899A > T (p.Gln300Leu)—in four independent families that were responsible for female infertility mainly characterized by preimplantation embryonic arrest. In vitro , we found that these variants reduced the interaction between MEI4 and DNA. In vivo , we generated a knock-in mouse model and demonstrated that female mice were infertile and were characterized by developmental defects during oogenesis. Our findings reveal the important roles of MEI4 in human reproduction and provide a new diagnostic marker for genetic counseling of clinical infertility patients.

IntroductionProgestin can inhibit the pituitary luteinising hormone (LH) surge during ovarian stimulation for in vitro fertilisation (IVF) and studies show progestin-primed ovarian stimulation (PPOS) is effective in blocking the LH surge in IVF. More and more centres are using PPOS because this regimen appears simpler and cheaper. This study aims to compare the euploidy rate of blastocysts following the PPOS protocol and the gonadotropin-releasing hormone antagonist protocol in women undergoing preimplantation genetic testing for aneuploidy (PGT-A).Methods/analysisThis is a randomised trial. A total of 400 women undergoing PGT-A will be enrolled and randomised according to a computer-generated randomisation list to either (1) the antagonist group: an antagonist given once daily from day 6 of ovarian stimulation till the day of the ovulation trigger; or (2) the PPOS group: dydrogesterone from the first day of ovarian stimulation till the day of ovulation trigger. The primary outcome is the euploidy rate of blastocysts.Ethics/disseminationAn ethical approval was granted from the ethics committee of assisted reproductive medicine in Shanghai JiAi Genetics and IVF institute (JIAIE2020-03). A written informed consent will be obtained from each woman before any study procedure is performed, according to good clinical practice. The results of this randomised trial will be disseminated in a peer-reviewed journal.Trial registration numberNCT04414748.