Purpose:Early human embryogenesis unfolds through a tightly coupled sequence of events-clearance of maternal transcripts, remodeling of parental chromatin, zygotic genome activation (ZGA), lineage segregation, implantation, and post-implantation patterning-accompanied by epigenetic reprogramming, including X-chromosome dosage compensation around the time of implantation. This review aims to synthesize recent advances in understanding this developmental program and to consider their implications for reproductive medicine. Methods:I review recent literature on human early embryogenesis, with particular emphasis on findings enabled by single-cell genomics and stem-cell-based embryo modeling, and integrate these insights to identify human-specific features of early development. Results:These approaches have made previously inaccessible aspects of human early embryogenesis experimentally tractable, revealing molecular and epigenetic features that distinguish human development from that of model organisms, including species-specific dynamics of ZGA, maternal transcript clearance, chromatin reprogramming, and X-chromosome dosage compensation. Conclusions:Advances in single-cell genomics and embryo modeling are transforming our understanding of human early embryogenesis. Building on these insights, while recognizing their current limitations, I propose a vision for improving reproductive medicine, including the potential for next-generation embryo selection strategies.
Objective:The present study aimed to investigate lipolytic function in cumulus cells (CCs) from women with polycystic ovary syndrome (PCOS), with a particular emphasis on the role of androgen excess. Study Design:Samples of follicular fluid and CCs were collected from 30 PCOS and 30 control subjects. Human primary CCs were cultured and treated with high doses of testosterone. Androgen and gene expression levels were measured by chemiluminescent immunoassay and quantitative reverse transcription polymerase chain reaction, respectively. Oil Red O staining followed by spectrophotometric analysis was conducted to quantify intracellular neutral lipids. Main Findings:CCs from PCOS patients showed significantly downregulated PNPLA2 and elevated G0S2 and HILPDA expression, with concomitant increased lipid droplet content (p < 0.05). The multivariable logistic regression model constructed from the combination of all three genes exhibited a superior diagnostic power (AUC = 0.837, p < 0.001). Only HILPDA expression was significantly correlated with intrafollicular testosterone (r = 0.395, p = 0.031), yet the main alterations observed in PCOS CCs were recapitulated in normal cells exposed to high doses of testosterone (p < 0.05). Conclusion:PCOS-associated hyperandrogenism appears to impair lipolysis in CCs, representing a potential mechanistic contributor to attendant compromised oocyte competence.
We commend Liang et al. for their rigorous meta-analysis of intrauterine platelet-rich plasma infusion in ART, particularly for recurrent implantation failure, but note issues affecting interpretation. Forest plot axes label "favors control/PRP" using a harm-oriented convention, inverting standard visual interpretation. The methods state a random-effects model, yet reported effect sizes and heterogeneity statistics match fixed-effect estimation, likely narrowing confidence intervals and overstating precision for live birth rate. One figure omits two included studies without explanation, undermining transparency. Non-significant subgroup findings are described as clinically meaningful, risking overinterpretation absent pre-specified hypotheses or multiplicity correction. Accurate, outcome-specific labeling and internally consistent model reporting are essential safeguards against misreading otherwise sound evidence, given its direct bearing on patient counseling and clinical decisions. We encourage a clarifying erratum to preserve this work's scientific integrity and clinical utility.
Background:Male infertility affects 8%-15% of couples, with male factors implicated in about half of cases; many remain idiopathic despite improved diagnostics. This narrative review addresses this gap by examining chronic inflammation as an underappreciated driver of sperm dysfunction that forms a bidirectional, self-reinforcing cycle with oxidative stress (OS). Methods:We synthesized studies from 2015 to 2025 identified via PubMed, Scopus, and Web of Science, examining links between inflammation and OS, key immune pathways, and related risk factors through qualitative narrative synthesis. Results:Inflammation drives leukocyte infiltration, blood-testis-barrier breakdown, antisperm-antibody production, and inflammasome activation, mechanisms that amplify OS and cause sperm DNA damage, impaired motility, apoptosis, and poor semen quality. Intrinsic factors (prostatitis, infection, varicocele) and extrinsic factors (obesity, aging, psychological stress) sustain this cycle through both ROS-dependent and ROS-independent, immune-mediated pathways. Paternal inflammation may also induce epigenetic changes in sperm with potential consequences for offspring health. Conclusion:Antioxidant monotherapy alone is often insufficient when an underlying immune driver persists. Immune-focused diagnostics combined with individualized, mechanism-based treatment strategies may improve personalized care and fertility outcomes.
Purpose:This study examined whether the application of public insurance on assisted reproductive technology in Japan was associated with changes in the incidence of multiple blastocyst transfer (MBT) and subsequent multiple pregnancies (MP). Methods:A total of 2764 blastocyst transfer cycles performed at IVF Osaka Clinic from the pre-insurance period (January 2020-March 2022) were retrospectively compared with 4,326 cycles from the insurance period (April 2022-February 2025). MP was defined as two or more gestational sacs. Results:Baseline analysis showed that patients' age after insurance coverage was significantly younger with fewer previous ET attempts than pre-insurance. MBT rose from 5.8% pre-insurance to 20.1% under insurance, and MP increased from 0.7% to 2.6%, simultaneously. Insurance coverage was independently associated with a higher likelihood of MBT, an association most pronounced in the older age cohort. MBT exhibited the highest risk profile for MP. Significant upward trends in MBT and MP were observed as patients approached their final insured cycles. Conclusions:Findings suggest a correlation between insured cycle limits and clinical practice toward prioritizing per-cycle success. Although alleviating financial burden, the policy appears to be associated with increased MBT and MP, making it necessary to deliberate its impact on maternal and neonatal safety.
Purpose:No biomarkers specific to true unexplained recurrent pregnancy loss (RPL) have yet been identified. This study aimed to investigate the lipid profile of patients with unexplained RPL using metabolomic analyses. Methods:Comprehensive serum metabolomic profiling was performed using liquid chromatography-tandem mass spectrometry. Lipid metabolites were analyzed using orthogonal partial least squares discriminant analysis. Results:The final analysis included serum samples from 31 healthy non-pregnant controls, 15 healthy pregnant controls, 32 non-pregnant patients with RPL, 19 pregnant patients with RPL and euploid miscarriage, and 30 pregnant patients with RPL and aneuploid miscarriage. Compared with controls, the non-pregnant RPL group exhibited higher levels of inflammation-related metabolites, including 11-dehydro-thromboxane B2 (11-dehydro-TXB2), 12-hydroxyeicosatetraenoic acid (HETE), and prostaglandin E2 (PGE2). Pregnant controls showed increased arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid metabolites. Comparisons between pregnant controls and patients with euploid or aneuploid miscarriages showed no clear separation. Enzyme-linked immunosorbent assay confirmed elevated serum 11-dehydro-TXB2 in non-pregnant patients with RPL. Conclusion:Patients with RPL display a distinct serum lipid signature in the non-pregnant state, characterized by elevated levels of pro-thrombotic and pro-inflammatory eicosanoids, including 11-dehydro-TXB2, 12-HETE, and PGE2. Further studies are warranted to clarify the potential utility of 11-dehydro-TXB2 as biomarkers for RPL.
Purpose:To evaluate the feasibility and performance of spent culture medium (SCM)-based non-invasive pre-implantation genetic testing for aneuploidy (niPGT-A) after 8 h of post-warming in vitrified-warmed human blastocysts, and to determine whether post-amplification library concentration improves SCM-based result interpretation. Methods:This study included 26 discarded vitrified-warmed blastocysts from 17 patients. After 8 h of post-warming culture, SCM was collected and analyzed by next-generation sequencing together with trophectoderm (TE) biopsy samples and whole blastocysts (WB). Concordance at the chromosome and category levels was evaluated between SCM and WB and between TE biopsy and WB, and the association of library concentration with performance and euploid probability was assessed. Results:SCM analysis was informative in 92.3% (24/26) of embryos. Chromosome-level concordance with WB was lower for SCM than for TE (30.8% vs. 57.7%), whereas category-level concordance was 69.2% for SCM and 76.9% for TE. Combining SCM category with library concentration improved prediction of euploid embryos (AUC 0.9527 vs. 0.8077, p = 0.0158). The leave-one-out cross-validated AUC of the combined model was 0.896. Conclusions:SCM-based niPGT-A after 8 h of post-warming culture is feasible in vitrified-warmed human blastocysts. Library concentration improves interpretation of SCM-based results and may help identify embryos likely to be euploid.
Purpose:To describe age-specific patterns of gonadotoxic alkylating-agent exposure and evaluate how the cyclophosphamide equivalent dose (CED) framework captures real-world exposure relevant to fertility preservation in females aged 0-43 years. Methods:This descriptive study used a Japanese claims database. Patients were classified as pediatric (< 15 years) or reproductive-age (15-43 years). Twelve alkylating agents were evaluated, and six CED-calculable agents were converted to CED. Results:Among approximately 3.86 million females, 0.04% of the pediatric cohort and 0.16% of the reproductive-age cohort were exposed to at least one alkylating agent. Total CED identified at least intermediate-risk exposure in 33% of exposed pediatric and 14% of exposed reproductive-age patients. Compared with single-agent assessment, summed total CED identified additional patients mainly in the pediatric group, corresponding to relative increases of 20.2% and 0.3%, respectively. Agents not included in the current CED formula accounted for 8.7% of all alkylating-agent prescription records, approximately 90% of which were observed in reproductive-age patients. Conclusions:CED captured alkylating-agent exposure differently by age group: summed CED added exposure information mainly in pediatric patients, whereas agents lacking conversion coefficients limited exposure capture in reproductive-age females. These findings support refinement of CED-based assessment while emphasizing exposure capture, not outcome prediction.
Purpose:Recurrent implantation failure (RIF) is linked to immune dysregulation. Although tacrolimus has shown clinical benefits in RIF, its immunological mechanisms remain unclear. We assessed its effects on peripheral blood NK cell subsets and cytokine profiles. Methods:Thirty women with RIF and 30 fertile controls were enrolled. Patients received oral tacrolimus (3 mg/day) before embryo transfer until pregnancy testing. NK cell subsets and IL-17/IL-10 expression were assessed by flow cytometry and real-time PCR before and after treatment. Results:At baseline, RIF patients showed higher NK cell-associated subsets and increased IL-17/IL-10 ratio compared with controls (CD16+: p = 0.019; CD56+: p < 0.0001; CD16+CD56+: p < 0.0001; IL-17/IL-10 ratio: p < 0.0001). Following tacrolimus, CD16+ (p = 0.011), CD56+ (p = 0.001), and CD16+CD56+ (p = 0.001) NK cells, as well as IL-17 levels (p < 0.0001) and the IL-17/IL-10 ratio (p = 0.0036), were significantly reduced, whereas IL-10 expression remained unchanged (p = 0.406). Greater reductions in the IL-17/IL-10 ratio were associated with clinical pregnancy (p = 0.048), suggesting predictive value for implantation success. Conclusions:Tacrolimus modulated immune pathways by reducing pro-inflammatory NK subsets and shifting the IL-17/IL-10 balance toward tolerance, supporting its potential as targeted immunotherapy in selected patients.
Purpose:This study aimed to compare outcomes of delaying oocyte retrieval beyond 40 h post-trigger with diclofenac versus the conventional workflow. Methods:A total of 4912 cycles were retrospectively screened. Eighty-four delayed cycles and 168 routine cycles from patients who received a single trigger in their first cycle were matched at a 1:2 ratio for age, AMH, COS protocol, and ICSI use and compared. Results:The ratio of the number of oocytes retrieved to the number of follicles ≥ 14 mm on trigger day was significantly higher in the delayed group (1.27 ± 0.42 vs. 1.14 ± 0.47, p = 0.031). The rates of maturation (78.9% vs. 78.8%), fertilization (64.0% vs. 64.6%), and blastulation (63.8% vs. 68.5%) were comparable (all p > 0.05). Biochemical pregnancy rates in fresh cycles were numerically lower in the delayed group (38.4% vs. 47.0%), while clinical pregnancy rates were similar between groups in both fresh (38.4% vs. 41.1%) and frozen-thawed cycles (51.2% vs. 52.8%) (all p > 0.05). Conclusions:Delaying oocyte retrieval beyond 40 h post-trigger with diclofenac could be feasible to enhance clinical operational flexibility. Further research is warranted to identify subgroups that may benefit most and to optimize strategies adapted to this extension.
Purpose:To evaluate whether time-lapse monitoring improves embryological outcomes and clinical pregnancy rates compared to conventional culture in a sibling-oocyte study. Methods:This multicenter-study involved 205 first-time retrieval cycles (n = 3244 mature oocytes). Sibling-oocytes from patients with ≥ 4 oocytes were randomized into conventional and time-lapse groups. The primary outcome was the good-quality blastocyst rate. Key secondary outcomes included Day-2 Good Quality Embryo (GQE) rates and clinical pregnancy rates for both fresh and frozen-thawed embryo transfers (FET). Results:The time-lapse group exhibited a significantly higher GQE rate on Day 2 (42.1% vs. 35.3%, p < 0.01) and a higher good-quality blastocyst rate (44.1% vs. 38.1%, p < 0.01) compared to the conventional group. While clinical pregnancy rates showed a higher trend in the time-lapse group for both fresh ET (44.4% vs. 15.8%) and FET (45.3% vs. 36.7%), these differences did not reach statistical significance. Time-lapse monitoring successfully identified embryos with early pronuclear disappearance as early as 14 h post-insemination. Morphokinetic analysis revealed that abnormal cleavage patterns were associated with significantly lower blastocyst development potential compared to normal cleavage (p < 0.01). Conclusion:Time-lapse culture provides a stable environment that enhances embryo quality. While clinical pregnancy rates showed a positive trend, further large-scale studies are needed to confirm the impact on live birth rates.
Purpose:To review the biological rationale, clinical evidence, limitations, and future directions for hormonal therapy before sperm retrieval in men with non-obstructive azoospermia (NOA), with emphasis on phenotype-based selection using the APHRODITE criteria. Methods:A narrative review was conducted, integrating evidence on hypothalamic-pituitary-gonadal axis regulation, Leydig- and Sertoli-cell function, intratesticular testosterone, gonadotropin-based stimulation, sperm retrieval outcomes, and endocrine phenotyping in NOA. Particular attention was given to mechanistic studies and controlled cohorts evaluating hCG, FSH, or combined gonadotropin therapy before microdissection testicular sperm extraction. Results:Hormonal therapy in NOA remains controversial because available studies are heterogeneous and largely observational. However, mechanistic data show that hormonal therapy using hCG can increase intratesticular testosterone and stimulate spermatogonial activity, while exogenous FSH may support Sertoli-cell function. Clinical evidence suggests that benefit is most likely in selected men with biochemical hypogonadism, especially those with normal or moderately elevated FSH, whereas men with advanced hypergonadotropic testicular failure appear less likely to respond. Conclusions:Hormonal therapy before sperm retrieval in testicular NOA should be considered a selective, off-label strategy rather than a universal intervention. APHRODITE-based stratification may help identify candidates for endocrine optimization and guide future randomized trials.
Purpose:To evaluate the clinical efficacy of ERPeakSM-guided personalized embryo transfer (pET) in recurrent implantation failure (RIF) and non-RIF patients, and assess the temporal stability of the window of implantation (WOI). Methods:This prospective cohort study included patients undergoing frozen embryo transfer (FET) with good-quality embryos. In hormone replacement therapy (HRT) cycles, RIF patients received pET (n = 199) or non-personalized ET (npET, n = 272); non-RIF patients received pET (n = 74) or npET (n = 351). Propensity score matching (PSM) adjusted for confounders. modified Natural cycle (mNC) FET was analyzed using inverse probability of treatment weighting (IPTW). WOI stability was evaluated via Kaplan-Meier analysis. Results:Following PSM in RIF patients, pET significantly improved live birth rates (LBR) compared to npET (41.0% vs. 23.6%, p < 0.001) and reduced miscarriage rates (17.4% vs. 36.2%, p = 0.014). In non-RIF patients, pET did not improve LBR (35.8% vs. 25.4%, p = 0.26). IPTW-adjusted mNC-FET analysis showed significantly higher LBR in the pET group (46.3% vs. 19.2%, p = 0.026). Kaplan-Meier analysis revealed WOI stability declines significantly faster in patients ≥ 38 years (median 30.0 months, p = 0.0059). Conclusions:ERPeakSM-guided pET significantly improves LBR in RIF patients undergoing HRT and mNC-FET, but lacks benefit in non-RIF patients. WOI is dynamic; reevaluation is recommended for older patients.
Purpose:Procarbazine, an alkylating agent, depletes ovarian reserve. Omegaven exhibits anti-apoptotic, anti-inflammatory, and antioxidant properties. We aimed to investigate the preventative benefits of Omegaven against the deleterious effects of Procarbazine on the ovaries. Methods:Thirty female rats were categorized into groups: Control, n = 6; Omegaven, n = 8; Procarbazine, n = 8; and Procarbazine+Omegaven, n = 8. Biochemical and histological analyses were conducted. Results:Total follicle count calculated from evaluated sections is significantly reduced in the Procarbazine group compared to other groups. Immunoreactivities of inflammatory and apoptotic markers were significantly elevated in the Procarbazine group and were diminished significantly in the Procarbazine+Omegaven group. In the Procarbazine group, ultrastructural alterations due to atresia were marked by the presence of lipid droplets, multivesicular bodies, and eosinophil infiltration. The ultrastructural alterations were less pronounced in the Procarbazine + Omegaven group. In the Procarbazine group, prooxidative, inflammatory, and apoptotic markers in ovarian tissue were elevated, while antioxidative indicators were significantly diminished. Blood chemistry analyses yielded comparable results. AMH levels were markedly reduced in the Procarbazine Group compared to the control group. The AMH levels in the Procarbazine + Omegaven group exhibit a rise significantly in blood serum samples. Conclusions:Omegaven is a promising pharmacological agent for mitigating the deleterious effects of Procarbazine on ovarian reserve.
Background:This meta-analysis evaluates the efficacy and safety of intrauterine autologous platelet-rich plasma (PRP) infusion in patients with recurrent implantation failure (RIF). Methods:Following PRISMA guidelines, we systematically searched major databases and included 10 randomized controlled trials (RCTs, n = 1 188). Study quality was assessed using the Cochrane RoB 2.0 tool. Results:PRP infusion significantly improved clinical pregnancy rate (RR = 2.23, 95% CI 1.84-2.69) and live birth rate (RR = 3.74, 95% CI 2.68-5.22) without increasing miscarriage risk. Subgroup analysis indicated that a 0.5 mL PRP volume was as effective as 0.5-1.0 mL, and a notably greater treatment effect was observed in blastocyst transfer cycles compared to cleavage-stage embryo transfers, suggesting potential enhanced benefit in this subgroup. Conclusion:Intrauterine PRP infusion is an effective and safe treatment for RIF. The findings on dose equivalence and differential efficacy by embryo stage offer valuable insights for optimizing clinical application.
Purpose:This study investigated whether perinatal complications in assisted reproductive technology are attributable to embryo cryopreservation or the specific endometrial preparation method, comparing Fresh Embryo Transfer (Fresh ET), Natural Cycle Frozen-thawed Embryo Transfer (NC-FET), and Hormone Replacement Cycle FET (HRC-FET). Methods:A retrospective cohort analysis of 7,593 live-birth cycles (908 Fresh ET, 4,707 HRC-FET, 1,978 NC-FET) performed from 2015 to 2023 was conducted. Multivariable analyses using generalized estimating equations, adjusted for endometrial preparation method, maternal age, BMI, history of delivery, and endometrial thickness, were conducted for the five major complications. Results:Compared with Fresh ET, HRC-FET was associated with significantly increased risks for hypertensive disorders of pregnancy, placenta accreta spectrum, and postpartum hemorrhage due to uterine atony. No significantly increased risks for these adverse outcomes were observed in association with NC-FET. No significant differences were observed for gestational diabetes or placenta previa across groups. Conclusions:The increased risks of adverse maternal and placental outcomes were associated with the HRC protocol rather than the cryopreservation process. These associations suggest that ovulatory-based endometrial preparation strategies, typically characterized by the presence of a corpus luteum, should be considered when medically and logistically feasible to enhance perinatal safety.
Purpose:Leukemia Inhibitory Factor (LIF) plays a crucial role in implantation and early pregnancy maintenance. However, its regulatory relationships with molecular markers such as Sirtuin 1 (SIRT1), immunoglobulin-like transcript 4 (ILT-4), and specific microRNAs (miRNA) in recurrent pregnancy loss (RPL) remain underexplored. Methods:This study investigates the effect of LIF on the expression of Sirt1, Ilt-4, and related miRNAs using a mouse model of RPL. Female CBA/J mice mated with DBA/2 J males received LIF treatment. Gene and miRNA expression levels were assessed via quantitative PCR. Results:The LIF-treated group showed significant upregulation of Sirt1 on Days 7 and 14. Ilt-4 expression also increased significantly on Days 7 and 14 in the LIF group. Among miRNAs, mir-138-5p was significantly upregulated on Day 14 (p = 0.0001), while mir-223-3p was downregulated on Days 7 (p = 0.02) and 14 (p = 0.001). mir-199a-5p showed significant downregulation on Days 7 (p < 0.0001) and 14 (p = 0.0001). Additionally, mir-155-5p demonstrated a significant decrease in the LIF-treated group compared to the PBS group (p < 0.0001). Conclusions:These results suggest that LIF modulates critical molecular pathways in RPL by influencing the expression of essential genes and miRNAs, highlighting its potential as a therapeutic target for pregnancy-related complications.
Purpose:This study aimed to develop international expert consensus statements on chronic endometritis (CE) through a comprehensive literature review of existing evidence and a modified Delphi approach. Methods:Ten panelists of the Japan Society of Reproductive Medicine Female Reproductive Tract Special Interest Group on CE performed a comprehensive review of the literature and derived statements with related comments on six specific domains of interest on CE. A two-round modified e-Delphi questionnaire was conducted among 31 international experts to evaluate the statements. Results:Twenty-three out of 24 statements, including 43 detailed items, on epidemiology (associated diseases and risk factors), symptomatology (asymptomatic or oligosymptomatic nature with subtle and nondescript gynecologic manifestations), etiology and pathogenesis (inflammation, infection, and clinical course), microbiology (associated pathogens), diagnosis (histopathology, immunohistochemistry, hysteroscopy, and microbiome analysis), and treatment (antibiotics, surgery, and multidrug resistance) finally reached a consensus. Notably, for the histopathologic diagnosis of CE, a threshold of ≥ 5 endometrial stromal plasma cells/10 high-power fields received an agreement rate of 81%. Conclusions:This comprehensive literature review and Delphi study provide a real-world clinical perspective on CE from diverse international experts. These consensus statements have the potential to lay a foundation for diagnostic criteria and/or clinical guidelines on CE.
Purpose:To evaluate the association between hysteroscopic treatment of cesarean scar disorder (CSDi), clinical improvement, and changes in the endometrial microbiome, as this remains unclear. Methods:This prospective observational study included 40 women diagnosed with symptomatic CSDi. Clinical outcomes, including symptom severity and ultrasonographic measurements, were assessed before and after hysteroscopic treatment. Endometrial microbiome analysis using 16S rRNA gene sequencing was performed in a predefined subgroup of 22 patients preoperatively and at 3 months postoperatively. Microbial composition and diversity were analyzed and correlated with clinical findings. Results:Hysteroscopic treatment resulted in a significant reduction in isthmocele dimensions and improvement in clinical symptoms across the entire cohort (p < 0.01). In the subgroup undergoing microbiome analysis, postoperative samples demonstrated a shift from a polymicrobial profile consisting mostly of Clostridia and Bacteroidia to a Lactobacillus-dominant microbial profile, accompanied by a decrease in microbial diversity (p < 0.001). These microbiological changes occurred in parallel with clinical improvement. Conclusions:Hysteroscopic treatment of CSDi is associated with favorable clinical outcomes and concurrent alterations in the endometrial microbiome. Although microbiome analyses were performed in a subset of patients, the findings suggest a potential relationship between anatomical correction and microbial environment. Larger, controlled studies are warranted to further elucidate this association.
