ABSTRACT Objective To clarify institutional perspectives on assisted reproductive technology (ART) using third‐party gametes. Methods We surveyed 634 facilities registered with the Japan Society of Obstetrics and Gynecology, and 416 responses were included in a descriptive analysis. Results Psychosocial and economic stability of ART recipient couples were considered necessary in most facilities (94.6%). Japanese nationality and legal marriage were necessary recipient criteria in 36.8% and 54.3% facilities, respectively. Lower and upper age limits for female recipients were 20–25 and 43–45 years, respectively, whereas most male partners had no upper age limit (34.6%–36.6%). The most common upper age limit for oocyte donors was 35 years (67.9%). In contrast, upper age limits for sperm donors were more dispersed, with 40 years being the most common age at response to intrauterine insemination (35.6%) and in vitro fertilization (35.9%). The most accepted indications were hypergonadotropic hypogonadism for oocyte donation (87.5%) and failure to retrieve sperm via micro‐testicular sperm extraction for donor sperm treatment (97.3%). Most facilities considered psychosocial support necessary. Conclusions This study provides a comprehensive overview of institutional perspectives on third‐party ART in Japan. Although facilities showed substantial agreement on core principles, their views on specific eligibility and operational criteria varied.
ABSTRACT Purpose Frozen embryo transfer ( FET ) is associated with increased maternal complications, but whether these risks are specific to the hormone replacement cycle ( HRC ‐ FET ) protocol or shared broadly across FET pregnancies remains unclear. This study compared perinatal outcomes among non‐ ART , fresh embryo transfer, ovulatory‐cycle FET ( OC ‐ FET ), and HRC ‐ FET pregnancies. Methods This was a single‐center retrospective cohort study of 5417 singleton deliveries (2017–2025), comprising 4427 non‐ ART , 158 fresh embryo transfer, 208 OC ‐ FET , and 624 HRC ‐ FET pregnancies. Multivariable logistic regression, adjusted for maternal age, BMI , and parity, was used to calculate adjusted odds ratios ( aORs ), with non‐ ART as the reference group. Results Compared with non‐ ART , HRC ‐ FET was associated with significantly increased risks of manual removal of the placenta ( aOR 14.54), postpartum hemorrhage ( aOR 2.33), and uterine atony ( aOR 3.23). These risks remained significant after stratifying by mode of delivery. In contrast, fresh embryo transfer and OC ‐ FET showed risk profiles resembling non‐ ART for most outcomes. Conclusion Increased perinatal risk associated with ART is not uniform but concentrated primarily in HRC ‐ FET . Perinatal management after HRC ‐ FET should account for bleeding‐related complications.
Purpose To investigate whether hydrosalpinx is associated with alterations in the endometrial microbiota and detection of gram-positive anaerobic cocci (GPAC)-associated genera.Methods This single-center retrospective observational study included 236 patients who underwent endometrial microbiota testing by 16S ribosomal RNA gene sequencing: 90 with untreated hydrosalpinx diagnosed by hysterosalpingography and 146 without hydrosalpinx. GPAC positivity was defined as detection of at least one of Anaerococcus, Finegoldia, Peptoniphilus, Peptostreptococcus, or Parvimonas. Logistic regression was adjusted for age, antibiotic use within 3 months, and luteal-phase sampling. False discovery rate adjustment was applied across four exploratory microbiota outcomes.Results GPAC-associated genera were detected in 23/90 patients (25.6%) with hydrosalpinx and 19/146 (13.0%) without hydrosalpinx. Hydrosalpinx was nominally associated with GPAC detection (adjusted odds ratio, 2.20; 95% confidence interval, 1.10-4.38; p = 0.025), but not after false discovery rate adjustment (q = 0.101). No clear associations were observed for the other microbiota outcomes. Similar estimates were obtained after additional adjustment for recurrent implantation failure and in post hoc sensitivity analyses using alternative GPAC definitions.Conclusion Hydrosalpinx was associated with more frequent detection of GPAC-associated genera in exploratory analyses. This finding should be considered hypothesis-generating rather than confirmatory and requires independent prospective validation.
ABSTRACT Background Varicocele is common in male infertility, yet many affected men retain conventional reproductive measures, and the anatomical grade is an imperfect proxy for phenotype. Established pathways explain injury more clearly than between‐person heterogeneity. Methods This structured, critical narrative review searched PubMed from 1 January 2015 to 26 August 2026, with targeted hand‐searching. There was no preregistered protocol, dual screening, or risk‐of‐bias assessment, and coverage is not exhaustive. Main Findings The threshold‐resilience framework is a hypothesis‐generating model separating lesion‐related exposure, candidate host response measures, and couple‐level variables. Human varicocele‐specific evidence supports hemodynamic, thermal, redox, and sperm DNA damage associations. No prospective human varicocele study was identified in which an independently measured antioxidant, DNA processing, heat response, or endocrine measure preserved fertility at a given exposure. Female age and ovarian reserve are couple‐level variables, and all candidate host response measures remain research‐only. Conclusion Intended for investigators in andrology and reproductive medicine, the framework is a research agenda rather than an explanatory mechanism or clinical algorithm. It maps evidence provenance, identifies measurement gaps, and specifies prospective tests of whether prespecified, outcome‐independent host response measures add prediction beyond anatomy, semen analysis, damage measures, and couple‐level factors.
ABSTRACT Background Intracytoplasmic sperm injection (ICSI) is widely used in assisted reproductive technology and achieves fertilization by directly injecting a spermatozoon into the oocyte cytoplasm. However, it requires deliberate disruption of the oolemma and bypasses physiological sperm–oocyte membrane fusion. Assisted sperm fusion insemination (ASFI) was developed to achieve fertilization through gamete membrane fusion without penetrating the oolemma. Methods This review summarizes the biological basis of sperm fusion competence, including acrosomal exocytosis, zona pellucida interaction, and molecular mechanisms of gamete membrane fusion, and reviews the development, technical procedure, clinical evidence, and current limitations of ASFI. Results ASFI uses motile zona pellucida‐bound spermatozoa that are recovered and pressed against the oolemma to facilitate membrane adhesion and fusion. Clinical studies have demonstrated fertilization, blastocyst development, and live birth after ASFI. In a prospective sibling‐oocyte study, ASFI achieved a higher normal fertilization rate than conventional ICSI (88.0% vs. 70.2%), with no oocyte degeneration (0% vs. 8.8%) and a higher usable embryo rate per MII oocyte (45.8% vs. 28.1%). Conclusion ASFI provides a fusion‐based alternative to direct sperm injection and may reduce procedure‐related oocyte degeneration. Further studies are required to establish zona‐independent sperm selection, technical standardization, and reproducibility across centers.
