OBJECTIVE:Mosaic embryos can yield healthy live births, although pregnancy outcomes are inferior to those with euploid embryos. Pregnancy outcomes also vary significantly among mosaic embryos with different characteristics, yet current classifications lack sufficient granularity to reflect this heterogeneity. However, prevailing classification systems lack sufficient granularity to adequately reflect this heterogeneity. The objective of this study is to delineate pregnancy outcome differences among mosaic embryos categorized using a refined classification framework that provides greater resolution of mosaicism characteristics. DESIGN:A retrospective study comparing the pregnancy outcomes of embryo transfer cycles transferring euploid and mosaic embryos. SUBJECTS:A total of 434 cycles of mosaic embryo transfers and 868 cycles of euploid embryo transfers were included. EXPOSURE:The euploid or mosaic embryos transferred and the characteristics of mosaicism. MAIN OUTCOME MEASURES:Clinical pregnancy rate, ongoing pregnancy rate, live birth rate, first-trimester pregnancy loss rate, incidence of maternal complications, and congenital anomalies. RESULTS:Generalized estimating equation (GEE) models were used to compare pregnancy outcomes between groups. Overall, mosaic embryos were associated with significantly inferior pregnancy outcomes than euploid embryos, driven primarily by high-level mosaic embryos. Compared with euploid embryos, the segmental mosaic embryos had similar pregnancy outcomes, whereas the chromosomal mosaic embryos had worse pregnancy outcomes, with lower clinical pregnancy rate (odds ratio [OR]=0.65; 95% confidence interval [CI]: 0.43-0.98), ongoing pregnancy rate (OR=0.56; 95%CI: 0.37-0.84), and live birth rate (OR=0.61; 95%CI: 0.41-0.92). Within chromosomal mosaic embryos, pregnancy outcomes did not differ significantly between monosomy mosaic and euploid embryos. In contrast, chromosomal trisomy mosaic embryos presented markedly worse outcomes than euploid embryos across all measures: biochemical pregnancy rate (OR=0.46; 95%CI: 0.25-0.83), clinical pregnancy rate (OR=0.48; 95%CI: 0.27-0.84), first-trimester pregnancy loss rate (OR=6.00; 95%CI: 1.99-18.11), ongoing pregnancy rate (OR=0.32; 95%CI: 0.18-0.58), and live birth rate (OR=0.35; 95%CI: 0.19-0.63). Finally, the incidence of maternal complications and congenital anomalies did not differ significantly between mosaic and euploid groups. CONCLUSION:Segmental and chromosomal monosomy mosaic embryos have pregnancy outcomes comparable with those of euploid embryos, whereas chromosomal trisomy mosaic embryos are associated with significantly poorer outcomes.

Objective: To investigate the relationship between the number of previous implantation failures (IFs) and embryo ploidy status, as well as subsequent clinical outcomes, in women with recurrent implantation failure (RIF) undergoing preimplantation genetic testing for aneuploidy (PGT-A). Methods: This retrospective cohort study included 422 women with RIF who underwent their first PGT-A cycle between 2017 and 2022. Participants were stratified by maternal age (<38 years, n = 292; ≥38 years, n = 130) and by the number of previous IFs, categorized as 3, 4, or ≥5. The primary outcomes were embryo ploidy rates (euploidy, aneuploidy, and mosaicism). Secondary outcomes included reproductive outcomes after single euploid blastocyst transfer (biochemical pregnancy, clinical pregnancy, ongoing pregnancy, live birth, and pregnancy loss) and neonatal birth weight. Results: Women aged ≥38 years had a significantly lower euploidy rate than those <38 years (24.8% vs. 47.3%, p < 0.001). Ploidy distribution did not differ significantly across IF categories. Among women aged <38 years with ≥5 IFs, a greater number of previous embryo transfer attempts was independently associated with higher odds of live birth after euploid embryo transfer (adjusted OR = 1.258, 95% CI: 1.051-1.505; p = 0.012). Neonatal weight did not differ significantly across IF categories. Conclusions: The number of previous IFs was not independently associated with embryo ploidy or clinical outcomes after euploid transfer, whereas advanced maternal age was strongly associated with a lower likelihood of obtaining euploid embryos. In younger women with ≥5 IFs, a greater number of previous embryo transfer attempts was associated with live birth after euploid transfer; however, this exploratory subgroup finding should be interpreted cautiously and requires prospective validation. Because this study did not directly evaluate therapeutic strategies, any potential role for individualized endometrial evaluation or optimization should be considered as hypothesis-generating rather than supported by the present data.

Embryo implantation failure and early pregnancy loss remain significant challenges in assisted reproductive technology (ART). Lipid peroxidation is known to be involved in reproductive physiology. However, its role during the implantation window and its effects on post-embryo transfer outcomes remain incompletely understood. This translational study combined clinical and animal model research. Clinically, serum samples (n = 2040) and uterine fluid samples (n = 487) from patients undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles were analyzed using propensity score matching (PSM), univariate and multivariate logistic regression analysis, restricted cubic spline (RCS) analysis, and subgroup analysis. A murine model of lipid peroxidation was established by administering erastin during the implantation window to investigate its effects on endometrial receptivity and decidualization. Elevated serum levels of malondialdehyde (MDA) and non-heme iron were independently associated with recurrent implantation failure (RIF). Among patients without RIF, elevated pre-transfer serum levels of MDA, non-heme iron, 12-hydroxyeicosatetraenoic acid (12-HETE), and 15-HETE were associated with implantation failure and early pregnancy loss. Consistent with this, intrauterine MDA levels were significantly higher in patients with these pregnancy failures compared to those with ongoing pregnancy. Complementary murine studies supported these clinical observations, showing that elevated lipid peroxidation during the maternal implantation window was associated with impaired endometrial receptivity and decidualization. Elevated maternal lipid peroxidation is independently associated with RIF. In patients without RIF, it is similarly associated with implantation failure and early pregnancy loss. The endometrium appears particularly sensitive to this peroxidation, which may impair receptivity and decidualization. These support further investigation of redox-modulating strategies in ART.

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.

Over the past decade, increasing attention has been paid to neurofluid (NF) drainage in the brain, particularly to the glymphatic system and intramural periarterial drainage (IPAD) pathway, which are responsible for substance transport in the brain and are highly dependent on astrocyte function. The dysfunction of these drainage pathways can lead to the accumulation of toxic substances and fluids, and contribute to various brain diseases, such as stroke and Alzheimer's disease. Since astrocytes in the brain closely connect to the microvascular system with their endfeet, in this work, the roles of astrocytes in regulating the glymphatic system and IPAD pathway and their dysfunction in neurodegenerative diseases have been comprehensively reviewed. Additionally, the effects of aquaporin 4, a water channel protein located on astrocytic endfeet, on these two pathways are explored. Furthermore, the possible therapeutic strategies for brain diseases targeting the NF drainage systems have also been proposed and thoroughly discussed.

Preeclampsia (PE) is a major hypertensive disorder of pregnancy and a leading cause of maternal and perinatal mortality and morbidity worldwide. Aberrant placental development, characterized by shallow trophoblast invasion and incomplete remodeling of maternal spiral arteries, remains central to PE pathogenesis. In PE, tissue transglutaminase (TGM2) is dysregulated in the placenta, contributing to vascular dysfunction, inflammation, and impaired trophoblast differentiation, yet the upstream regulatory signals remain unknown. Bone morphogenetic protein 7 (BMP7) is abundantly expressed at the maternal-fetal interface and implicated in vascular homeostasis, but its role in regulating trophoblast function, especially related to PE pathogenesis, remains undefined. Here, single-cell transcriptomic profiling of placental tissues revealed coordinated downregulation of BMP7 and upregulation of TGM2 in PE relative to normotensive controls. Functional assays in immortalized and primary human trophoblasts demonstrated that BMP7 promotes trophoblast migration and invasion by suppressing TGM2 expression through the ALK2/3-SMAD1/5/9-SMAD4 pathway. Trophoblast organoid models further demonstrated the anti-invasive role of TGM2 in trophoblast differentiation during early placentation. In vivo, an adenovirus-expressing sFlt-1 (Ad sFlt-1)-induced PE mouse model showed increased placental Tgm2 expression, while recombinant BMP7 administration ameliorated PE-like symptoms. Although the protective effects of BMP7 in vivo are likely mediated by mechanisms beyond TGM2 alone, together these findings identify the BMP7-TGM2 axis as an important trophoblast-regulatory mechanism in PE and support BMP7 as a potential therapeutic candidate.

The homeostasis of the Neurovascular Unit (NVU), a basic functional unit of the brain, is essential for neurological recovery. Glioblastoma-derived exosomes (Exos) have been demonstrated to enhance angiogenesis under hypoxic conditions, but their reparative potential in non-tumor ischemic microenvironments remain unclear. Moreover, free Exos are limited by rapid clearance, poor lesion retention, and uncontrolled release. Herein, we prepared an injectable chitosan hydrogel loaded with A172 cell-derived Exos (H-A-Exos) for intranasal delivery and evaluated its therapeutic effects in a rat middle cerebral artery occlusion (MCAO) model. In vitro, A-Exos facilitated endothelial cell proliferation, migration, and vascular endothelial growth factor (VEGF) expression, while inhibiting NVU cell apoptosis and reducing oxidative stress and inflammatory responses. When loaded within an injectable chitosan hydrogel, A-Exos exhibited enhanced retention and sustained release, resulting in improved accumulation in the ischemic infarct area following intranasal administration. Compared to the model group, H-A-Exos significantly improved behavioral recovery, as evidenced by a reduced modified Neurological Severity Score (mNSS), and decreased cerebral infarct volume (13.02 ± 1.01%), showing superior efficacy to free A-Exos and Nimodipine (NMDP). Mechanistically, H-A-Exos upregulated eNOS, Bcl-2, VEGF and CD31 expression, thereby promoting vascular regeneration and NVU remodeling. Thus, these findings confirm the effective pro-angiogenic and reparative roles of A-Exos in a non-tumor ischemic microenvironment and demonstrate that intranasal H-A-Exos represents a promising therapeutic strategy for restoring NVU homeostasis and enhancing revascularization following ischemic stroke, underscoring their innovative therapeutic potential.

In this study, we aimed to investigate the influence of paternal oligozoospermia (OZ), asthenozoospermia (AZ), or teratozoospermia (TZ) on blastocyst ploidy and its potential interaction with maternal age. We analyzed 3383 embryos in 1091 preimplantation genetic testing for aneuploidy (PGT-A) cycles via next-generation sequencing (NGS) at the Center for Reproductive Medicine, Shandong University (Jinan, China). Our findings revealed that compared to the normozoospermic (NZ) group, the AZ group exhibited significantly lower euploidy rates ( P = 0.022). This effect was more pronounced in cases with advanced maternal age (AMA; ≥38 years), where AZ patients had markedly reduced euploidy rates ( P = 0.003), while no significant differences were observed in younger women (<38 years). Multivariate analysis, adjusting for parental age and body mass index (BMI), confirmed that AZ is an independent risk factor for reduced euploidy rates in the AMA subgroup. Notably, OZ and TZ cases showed no significant association with blastocyst ploidy rates. These results suggest that only in cases of advanced maternal age, impaired sperm motility adversely affect blastocyst euploidy rates.

Recurrent pregnancy loss (RPL) is a distressing pregnancy disorder experienced by ~2.5% of women who try to conceive. Dysregulation of decidual function is an important factor leading to RPL, but the underlying genetic factors remain unknown. We discovered that the methyltransferase SETD1B and a non-coding circular RNA (circSTK40) were significantly down-regulated in the decidual tissue of RPL patients compared to those with healthy pregnancies. SETD1B knockdown resulted in increased apoptosis, decreased autophagy, and increased glycolysis, which could disrupt decidual function among those with RPL. Circstk40 overexpression upregulated SETD1B and alleviated apoptosis, lactic acid accumulation, and autophagy inhibition. Mechanistically, circSTK40 bound to both SETD1B and histone H3, promoting interactions between the two proteins and consequently increasing H3K4 methylation levels. H3K4me2 and H3K4me3 modifications in the SETD1B promoter enhanced transcription of this gene, forming a putative positive feedback loop between SETD1B and H3K4me2/H3K4me3. SETD1B and circSTK40 coordinately promoted decidua survival and function for pregnancy maintenance. Our findings reveal a novel molecular mechanism underlying RPL, providing valuable targets for future research into functional RPL treatments.

BACKGROUND:Preimplantation genetic testing for aneuploidy (PGT-A) is widely used to screen for aneuploidy with the aim of improving the live birth rate. Remarkably, previous studies have focused on the effect of PGT-A on cumulative clinical outcomes in women with a good pregnancy prognosis. However, it is still unclear whether PGT-A is superior for cumulative pregnancy outcomes in patients with limited good-quality embryos. METHODS:In total, 1553 patients who intended to pursue PGT-A for the first time but only obtained two or fewer good-quality embryos on day 3 after oocyte retrieval were divided into two groups: 997 in the PGT-A group and 556 in the drop-out group (i.e., decided not to undergo PGT-A due to poor embryological outcome). The main outcome measures were cumulative live birth rate per oocyte retrieval cycle and live birth rate per embryo transfer (ET) cycle. RESULTS:After adjustment for potential confounders, the PGT-A group exhibited significantly lower cumulative rates of biochemical pregnancy [19.96 % vs. 30.22 %, p-adjusted (p-adj) < 0.001], clinical pregnancy (17.55 % vs. 23.38 %, p-adj < 0.001) and live birth (14.14 % vs. 16.19 %, p-adj = 0.005) per oocyte retrieval compared with the drop-out group. In contrast, when analysed per ET procedure, the PGT-A group showed marked improvements in rates of biochemical pregnancy (72.16 % vs. 35.50 %, p-adj < 0.001), clinical pregnancy (61.86 % vs. 26.98 %, p-adj < 0.001) and live birth (48.45 % vs. 18.26 %, p-adj < 0.001) compared with the drop-out group. No significant differences were observed in cumulative miscarriage and ectopic pregnancy rates, number of ETs per live birth, and neonatal outcomes between the groups. CONCLUSIONS:This retrospective study of patients with limited good-quality embryos found that the PGT-A group had a lower cumulative live birth rate per oocyte retrieval, but superior pregnancy outcomes per ET compared with the drop-out group.

Objective To test the hypothesis that a freeze-all strategy would increase the chance of live birth compared with fresh embryo transfer in women with low prognosis for in vitro fertilisation (IVF) treatment. Design Pragmatic, multicentre, randomised controlled trial. Setting Nine academic fertility centres in China. Participants 838 women with a low prognosis for IVF treatment defined by ≤9 oocytes retrieved or poor ovarian reserve (antral follicle count <5 or serum anti-Müllerian hormone level <8.6 pmol/L). Interventions Eligible participants were randomised (1:1) to undergo either frozen embryo transfer or fresh embryo transfer on the day of oocyte retrieval. Participants in the frozen embryo transfer group had all of their embryos cryopreserved and underwent frozen embryo transfer later. Participants in the fresh embryo transfer group underwent fresh embryo transfer after oocyte retrieval. Main outcome measures The primary outcome was live birth, defined as the delivery of neonates with a heartbeat and respiration at ≥28 weeks’ gestation. Secondary outcomes were clinical pregnancy, singleton or twin pregnancy, pregnancy loss, ectopic pregnancy, birth weight, maternal and neonatal complications, and cumulative live birth after embryo transfers within one year after randomisation. Results In an intention-to-treat analysis, the rate of live birth was lower in the frozen embryo transfer group than in the fresh embryo transfer group (32% (132 of 419) v 40% (168 of 419); relative ratio 0.79 (95% confidence interval 0.65 to 0.94); P=0.009). The frozen embryo group had a lower rate of clinical pregnancy than the fresh embryo group (39% (164 of 419) v 47% (197 of 419); 0.83 (0.71 to 0.97)). The cumulative live birth rate was lower in the frozen embryo transfer group compared with the fresh embryo transfer group (44% (185 of 419) v 51% (215 of 419), 0.86 (0.75 to 0.99)). No difference was observed in birth weight, incidence of obstetric complications, or risk of neonatal morbidities. Conclusions Fresh embryo transfer may be a better choice for women with low prognosis in terms of live birth rate compared with a freeze-all strategy. The treatment strategies that prevent fresh embryo transfers, such as accumulating embryos with back-to-back cycles or performing routine preimplantation genetic testing for aneuploidy, warrant further studies in women with a low prognosis. Trial registration Chinese Clinical Trial Registry ChiCTR2100050168.

The transport of molecules within the brain extracellular space (ECS) plays a pivotal role in governing sleep patterns, memory formation, and the ageing process in organisms. Isolating and delineating the ECS is crucial for constructing accurate models of molecular dynamics within the intricate neuronal networks. However, the segmentation of the ECS has proven to be a formidable challenge due to its complex morphology, and there is a notable lack of comprehensive studies on such a topic. In this study, we have constructed an exclusive dataset for ECS segmentation, utilizing an advanced imaging technique enabled by cryo-electron microscopy. We introduce ECS-Net, a dedicated segmentation pipeline that integrates contrastive learning approach and shape-aware function. The contrastive learning strategy is employed to effectively differentiate the extracellular space from surrounding neural elements, while the shape-aware function is designed to bolster the model’s sensitivity to the distinctive structures of the ECS. The experimental results indicate that ECS-Net significantly outperforms existing methods in ECS segmentation, achieving an F1-score (F1) that is 2.91% higher and an Intersection-over-union (IOU) that is 4.62% superior on the ECSseg-1 dataset. Moreover, our model exhibits robust generalization capabilities when applied to an independent validation dataset. In summary, this study marks the establishment of the first cascaded network tailored for brain ECS segmentation. Our method is poised to enhance the analysis of ECS structures within an extensive dataset, thereby offering a substantial contribution to the broader biomedical research community.

PURPOSE:To investigate the impact of serum luteinizing hormone (LH) levels on the day of human chorionic gonadotropin (hCG) trigger on cumulative live birth in women undergoing in vitro fertilization (IVF) cycles. METHODS:This was a secondary analysis of a multicenter randomized controlled trial (NCT03118141). A total of 1212 infertile women undergoing their first IVF cycle with a good prognosis for live birth were included. Participants were stratified into three groups according to tertiles of serum LH levels on the hCG trigger day (hLH): low-hLH (< 1.28 IU/L), medium-hLH (1.28-3.26 IU/L), and high-hLH (> 3.26 IU/L). Logistic regression and restricted cubic spline models were used to evaluate associations, adjusting for maternal age, body mass index, and baseline hormones. RESULTS:Compared to the medium-hLH group, the low-hLH group exhibited significantly lower cumulative clinical pregnancy and live birth rates, along with a higher biochemical pregnancy loss rate (P < 0.05). The high-hLH group demonstrated a reduced cumulative live birth rate, while other pregnancy outcomes were comparable to the medium-hLH group. A restricted cubic spline analysis revealed a significant nonlinear, inverted U-shaped relationship between serum hLH levels and cumulative live birth rates, with the optimal threshold around 1.95 IU/L. Stratified analysis indicated that the impact of hLH levels was more pronounced in women undergoing GnRH antagonist protocols. CONCLUSIONS:Serum hLH levels exhibit a nonlinear association with cumulative live birth rates in IVF cycles, highlighting 1.95 IU/L as a potential threshold. Individualized adjustment of hLH levels may improve pregnancy outcomes, especially in GnRH antagonist protocols.

This study aimed to explore whether different controlled ovarian hyperstimulation (COH) protocols were associated with the incidence of aneuploid blastocysts in cycles undergoing preimplantation genetic testing for aneuploidy (PGT-A). A retrospective analysis was conducted on 5525 blastocysts from 1722 women (21–37 years old) who underwent PGT-A cycles utilizing next-generation sequencing (NGS). The cohorts included 240 cycles employing the gonadotropin-releasing hormone agonist (GnRH-a) short protocol, 698 cycles using the GnRH-a long protocol, and 784 cycles utilizing the GnRH antagonist (GnRH-ant) protocol. A significantly elevated rate of blastocyst aneuploidy was observed in the GnRH-a short protocol group relative to both the long protocol and antagonist protocol groups (44.05

Polycystic ovary syndrome (PCOS) is a common and heterogeneous endocrine disorder that affects 11%-13% of women worldwide, with profound implications for fertility and long-term metabolic health. Here we identify four reproducible subtypes-PCOS with hyperandrogen, with obesity, with high-sex hormone-binding globulin and with high-luteinizing hormone-anti-Müllerian hormone-through unsupervised clustering of 9 clinical variables in 11,908 affected women, validated across 5 international cohorts. Prospective 6.5-year follow-up and in vitro fertilization treatment data revealed distinct reproductive and metabolic trajectories: hyperandrogenic PCOS showed the highest risk of second trimester pregnancy loss and dyslipidemia incidence; PCOS with obesity exhibited the most severe metabolic complications, lowest live birth rates and highest PCOS remission rate; PCOS with high-sex hormone-binding globulin demonstrated favorable reproductive outcomes and the lowest incidence of diabetes and hypertension; and PCOS with high-luteinizing hormone-anti-Müllerian hormone had the greatest risk of ovarian hyperstimulation and the lowest PCOS remission rate. These findings advance understanding of PCOS heterogeneity and provide a framework for subtype-based risk stratification and personalized management.

Defective endometrial receptivity represents an important factor in recurrent implantation failure (RIF), though its precise regulatory mechanisms remain unclear. While nicotinamide N-methyltransferase (NNMT) is abundantly expressed in human endometrial tissues, its role in endometrial receptivity and RIF pathogenesis has not been defined. This study demonstrated that NNMT expression was significantly downregulated in midluteal-phase endometrium from RIF patients relative to fertile controls. Functional analyses in human endometrial stromal cells (ESCs) revealed that NNMT knockdown enhanced autophagy flux and disrupted progesterone signaling. Mechanistically, NNMT deficiency elevated H3K9me3 enrichment at the Aldh1a3 promoter, suppressing its expression. Notably, knockdown of ALDH1A3 resulted in similar effects with NNMT downregulation, and exogenous rhALDH1A3 reversed the autophagy alterations and rescued progesterone signaling in NNMT-knockdown cells. In vivo, NNMT inhibition in a murine model reduced embryo implantation rates and decreased ALDH1A3 expression. Collectively, these findings indicate that reduced NNMT impairs endometrial receptivity through H3K9me3-mediated ALDH1A3 repression, leading to aberrant autophagy and disrupted progesterone signaling in decidualized ESCs. This study identifies the NNMT-H3K9me3-ALDH1A3 axis as a key epigenetic-metabolic pathway underlying RIF, offering novel diagnostic and therapeutic targets.

While zygotes lacking pronuclei (0PN) or exhibiting a single pronucleus (1PN) may theoretically yield diploid embryos with developmental potential, current clinical protocols predominantly exclude these embryos from use. In the population undergoing preimplantation genetic testing for structural rearrangements (PGT-SR), there is a high rate of chromosomal aneuploidy abnormalities and needs a large number of embryos to obtain euploid embryos, so we will explore whether 0PN and 1PN embryos can be an option for them. This retrospective analysis examined pronuclear development in 4,868 zygotes derived from 4,902 injected metaphase II (MII) oocytes across 422 assisted reproductive cycles. In a subset of 54 cycles (12.8