Ideal animal models are needed to reflect the changes in the biochemical and biomechanical properties of the vagina that occur in pelvic organ prolapse (POP). In this study, we aimed to demonstrate the short and long-term effect of menopause on the biochemical and biomechanical properties of rat anterior vaginas. Here, Sprague-Dawley rats were bilaterally ovariectomized to induce menopause. Rats without ovariectomy served as the normal control group (n=12). The histology changes and the expression of collagen I, III, and a-SMA were assessed to indicate the biochemical changes in the vagina 2 weeks, 4 weeks, and 16 weeks after ovariectomy (n=6 for 2 and 4 weeks, n=12 for 16 weeks). Uniaxial biomechanical testing was conducted in the control group and ovariectomized rats 16 weeks after ovariectomy. Compared with the control group, the ovariectomy group showed a significant increase in the expression of collagen I 2 weeks after ovariectomy, while collagen III showed a declining trend. Two weeks after ovariectomy, the smooth muscle bundles began to become disorganized, and the fraction of smooth muscle in the nonvascular muscularis of the proximal vagina was significantly decreased (P<0.001). However, there was no difference in the expression of a-SMA in the distal vagina. Compared with the control group, the ovariectomy group had stiffer vaginas with a declining trend in the ultimate load 16 weeks after ovariectomy. In conclusion, surgically induced menopause had a significant short- and long-term impact on tissue composition and biomechanical properties of the rat vagina, which may lead to increased susceptibility to POP development.

What are the roles of maternal 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T/A1298C combination polymorphisms on the embryological and clinical outcomes of IVF/ICSI? Our study reveals for the first time that the oocyte maturation potential gradually decreases with a reduction of maternal MTHFR activity determined by combined C677T/A1298C polymorphisms, while embryo quality was worse in women with intermediate MTHFR activity. Although many previous studies have explored the association between MTHFR polymorphisms and IVF/ICSI outcomes, the results remain contradictory due to inadequate samples, no adjustment for potential confounders and/or the study of C677T and A1298C separately. Few studies have systematically investigated the exact role of MTHFR activity determined by combined C677T/A1298C polymorphisms on the embryological and clinical outcomes of IVF/ICSI. This is a retrospective cohort study investigating 1160 women who were referred for MTHFR genotyping and IVF/ICSI treatment at Peking University Third Hospital from May 2017 to May 2020. Women who were referred for MTHFR genotyping and their first IVF/ICSI treatment at our hospital were included and those undergoing preimplantation genetic testing cycles were excluded. The included women were divided into different cohorts according to their C677T, A1298C and combined C677T/A1298C genotypes. The embryological outcomes, including oocytes retrieved, metaphase II oocytes, oocyte maturation rate, normal fertilization rate and transplantable embryo rate, were evaluated by generalized linear regression models. The clinical outcomes, including biochemical pregnancy rate, clinical pregnancy rate and live birth rate, were evaluated by log-binomial regression models. All outcomes were adjusted for potential confounders. Women with the combined 677TT/1298AA genotype (hereafter abbreviated as TT/AA, as with other combined genotypes), whose enzyme activity was the lowest, had a lower oocyte maturation rate compared with those with the wild-type genotype (P = 0.007). Moreover, the oocyte maturation rate decreased linearly with the decline in MTHFR enzyme activity determined by combined C677T/A1298C genotypes (P-trend = 0.001). The combined CC/AC, CC/CC&CT/AA and CT/AC genotypes with intermediate enzyme activity were associated with a lower transplantable embryo rate (P = 0.013, 0.030 and 0.039, respectively). The differences in clinical outcomes between women with wild-type genotype and combined C677T/A1298C variant genotypes were not significant. Our study population had comparable embryological outcomes but worse clinical outcomes than other women undergoing IVF/ICSI treatment at our hospital. Therefore, the results related to the clinical outcomes should be generalized with caution. In addition, we did not detect the folate concentration of each patient during pregnancy. However, this might not have much influence on our results because almost all of our study participants took sufficient folic acid around pregnancy. We provide a holistic view of the effect of MTHFR C677T and A1298C polymorphisms on the IVF/ICSI outcomes, which can contribute to providing reasonable folic acid supplementation suggestions for women with different MTHFR genotypes, especially for those with a low oocyte maturation rate and/or low embryo quality. This work was funded by the National Natural Science Foundation of China (31871447, and 82101677), the National Key Research and Development Program (2019YFA0801400) and the Natural Science Foundation of Beijing Municipality (7202226). The authors declare that they have no competing interests. N/A.

Objective: To study the impact of congenital uterine anomalies on reproductive outcomes after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)-embryo transfer (ET). Methods: A retrospective study including a total of 865women with congenital uterine anomalies and 865 age and admission time matched controls who underwent the first IVF/ICSI-ET cycle between January 2010 and December 2019 was conducted. Women with uterine anomalies were classified into canalization defect (complete septate uterus and subseptate uterus) and unification defect (unicornuate uterus, bicornuate uterus, and didelphus uterus) according to the processes of abnormal embryological development. Control women were selected by age (± 1.0 year) and admission time (± 6 months) matched with a 1:1 ratio. The reproductive outcomes were compared between women with uterine anomalies and the controls. The primary outcome was live birth; secondary outcomes were clinical pregnancy, ectopic pregnancy, preterm delivery, and spontaneous pregnancy loss. Results: Compared with women with a normal uterus, women with canalization defects were less likely to experience live birth [84/332 (25.3%) vs 128/332 (38.6%), RR: 0.647, 95% CI 0.513–0.815, P < 0.001]. They also had a lower clinical pregnancy rate [126/332 (38.0%) vs 206/332 (62.0%), RR: 0.829, 95% CI 0.690–0.997, P = 0.046] and experienced a higher first-trimester pregnancy loss rate [25/126 (19.8%) vs 11/206 (5.3%), RR: 2.716, 95% CI 1.393–5.295, P = 0.003]. Compared with women with a normal uterus, women with a unification defect were also less likely to experience live birth [132/533 (24.8%) vs 219/533 (41.1%), RR: 0.713, 95% CI 0.586–0.868, P = 0.001]. Women with a unification defect had lower clinical pregnancy rates [182/533 (34.1%) vs 263/533 (49.1%), RR: 0.813, 95% CI 0.695–0.952, P = 0.010] and increased first-trimester pregnancy loss [36/182 (19.8%) vs 20/263 (7.6%), RR: 3.288, 95% CI 1.776–6.085, P < 0.001]. While uterine anomaly seemed not increase the risk of preterm birth, ectopic pregnancy and second-trimester pregnancy loss. Conclusions: Both canalization defects and unification defects were associated with lower fertility outcomes, including lower live birth rates, lower clinical pregnancy rates, and higher early miscarriage rates.

Objective: This retrospective study aimed to assess the impact of hysteroscopic septum incision on in vitro fertilization (IVF) outcomes among infertile women diagnosed with a complete septate uterus and no history of recurrent pregnancy loss. Methods: The study was conducted at a tertiary reproductive center affiliated with a university hospital and involved 78 women with a complete septate uterus. Among them, 34 women underwent hysteroscopic septum incision, while 44 women opted for expectant management. The primary outcome measure was the live birth rate, while secondary outcomes included clinical pregnancy rate, preterm birth rate, miscarriage rate, and ongoing pregnancy rate. Results: Women who underwent hysteroscopic septum incision demonstrated a comparable likelihood of achieving a live birth compared to those managed expectantly (25% vs. 25%, Relative Risk (RR): 1.000, 95% Confidence Interval (CI): 0.822 to 1.216). No preterm births occurred in either group. The clinical pregnancy rate, ongoing pregnancy rate, and miscarriage rate showed no significant differences between the surgical group and the expectant management group. Subgroup analyses based on the type of embryo transferred also revealed no significant differences in outcomes. Conclusions: Hysteroscopic septum incision does not appear to yield improved IVF outcomes compared to expectant management in infertile women with a complete septate uterus and no history of recurrent pregnancy loss.

Distal vaginal atresia is a rare abnormality of female reproductive tract in which the vagina is closed or absent. The distal vagina may be replaced by fibrous tissue and the condition is often not diagnosed until a girl fails to begin having periods at puberty. Although it is a congenital disorder, potential genetic causes of distal vaginal atresia are still unknown. We recruited a cohort of 39 patients with distal vaginal atresia and analyzed their phenotypic and genetic features. In addition to the complaint of distal vaginal atresia, approximately 17.9% (7/39) of the patients had other Müllerian anomalies, and 17.9% (7/39) of the patients had other structural abnormalities, including renal-tract, skeletal and cardiac anomalies. Using genome sequencing, we identified two fragment duplications on 17q12 encompassing HNF1B and LHX1, two dosage-sensitive genes with candidate pathogenic variants, in two unrelated patients. A large fragment of uniparental disomy was detected in another patient, affecting genes involved in cell morphogenesis and connective tissue development. Additionally, we reported two variants on TBX3 and AXL, leading to distal vaginal atresia in mutated mouse model, in our clinical subjects for the first time. Essential biological functions of these detected genes with pathogenic variants included regulating reproductive development and cell fate and patterning during embryogenesis. We displayed the comprehensive clinical and genetic characteristic of a cohort with distal vaginal atresia and they were highly heterogeneous both phenotypically and genetically. The duplication of 17q12 in our cohort could help to expand its phenotypic spectrum and potential contribution to the distal vaginal atresia. Our findings of pathogenic genetic variants and associated phenotypes in our cohort could provide evidence and new insight for further research attempting to reveal genetic causes of distal vaginal atresia.