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Background and Aims: Little information is available for investigating the effect of the direction of sperm injected into the cytoplasm on clinical results for human oocytes following intracytoplasmic sperm injection (ICSI). This study aimed to examine the impact of the direction of sperm (head-first or tail-first) injected into the cytoplasm on fertilization and embryo development for high-elasticity or low-elasticity human oocytes following the Piezo-ICSI. Methods: We retrospectively investigated 2717 high-elasticity oocytes and 907 low-elasticity oocytes between May 2016 and December 2022. Of 2717 high-elasticity oocytes, 1148 were injected sperm head-first, and 1569 were injected sperm tail-first into the cytoplasm by Piezo-ICSI. Of 907 low-elasticity oocytes, 480 were injected head-first, and 427 were injected sperm tail-first into the cytoplasm. The membrane of high-elasticity oocytes was robust and was ruptured artificially by the piezo-pulse. The membrane of low-elasticity oocytes was weak and spontaneously ruptured without the piezo-pulse. The rates of degeneration, fertilization (2PN), 0PN, 1PN, [Formula: see text]3PN, abnormal cleavage, and good-quality day-3 embryos were evaluated in both groups. Results: Table 1 shows the effect of sperm direction on fertilization and embryo development for high-elasticity oocytes. The fertilization rate of tail-first group was significantly higher than the head-first group. The 0PN rate of tail-first group was significantly lower than the head-first group. The good quality Day-3 embryo rate of tail-first group was significantly higher than the head-first group. Table 2 shows the effect of sperm direction on fertilization and embryo development for low-elasticity oocytes. The fertilization rate of the tail-first group was significantly higher than the head-first group. However, no significant difference was observed in other comparable items. Conclusions: Tail-first sperm injection significantly improved the fertilization rates more than the head-first sperm injection regardless of the elasticity of the oocyte membrane following Piezo-ICSI.

Several studies have reported that vitamin D may modify human reproductive functions; however, the results are conflicting. We aimed to comprehensively evaluate serum vitamin D levels and examine the relationship between serum vitamin D levels and ovarian reserve markers, and immune markers of implantation, in reproductive-aged Japanese women with infertility.in reproductive-aged women with infertility. This cross-sectional, single-center study included reproductive-aged women who underwent preconception screening for fertility. Serum vitamin D levels and reproductive and immune markers were measured. Standard and advanced statistical techniques were used. We observed a statistically significant difference in the seasonal and monthly 25(OH) vitamin D levels; the 25(OH) vitamin D level during winter was the lowest among all seasons. However, there was no linear correlation between 25(OH) vitamin D levels and ovarian reserve markers, such as follicle-stimulating hormone and anti-Müllerian hormone, or the Th1/Th2 cell ratio, which is used as an implantation-related immunological marker. In this large-scale study, we evaluated the serum 25(OH) vitamin D concentration in reproductive-aged women with infertility in Japan; however, there was no association between reproductive function and vitamin D levels.

Purpose: Male infertility is partially caused by an inappropriate lifestyle and comorbidities. In this study, we analyzed the prevalence of these factors and the effects of lifestyle modifications as part of male preconception care. Methods: Four hundred and two male partners of couples seeking conception with abnormal parameters upon the first semen analysis were enrolled. They were advised to modify their inappropriate lifestyle as male preconception care. Afterward, their general and male reproductive health was examined. Semen quality was compared before and after the promotion. Results: Smoking, chronic alcohol use, and genital heat stress were found in 22.6%, 47.0%, and 75.1% of patients, respectively. Palpable varicoceles, hypogonadism, obesity (body mass index ≧30 kg/m2), hypertension, zinc deficiency, hyperlipidemia, liver dysfunction, and diabetes mellitus were found in 25.9%, 17.0%, 7.0%, 14.9%, 16.2%, 37.0%, 26.9% and 3.4% of the participants, respectively; 98.8% of the patients had at least one factor. After the promotion, semen parameters and sperm DNA fragmentation were improved significantly. Improvement was found in those with palpable varicocele or hypogonadism but not in those with night work shift, abstinence (>3 days), erectile dysfunction, hypertension, obesity, zinc deficiency, or diabetes mellitus. Conclusions: Comorbidities and inappropriate lifestyle choices were common among men with infertility. The promotion of lifestyle modifications as part of male preconception care could improve semen quality without urologic intervention.

Background: Empty follicle syndrome (EFS) is a rare complication in which no oocytes are retrieved in oocyte pick-up (OPU) despite adequate controlled ovarian hyperstimulation (COH). Various studies and systematic reviews have reported that EFS is mainly caused by diminished ovarian reserve (DOR) because EFS tends to occur in patients with a poor response to COH. However, these factors do not explain all cases. Current knowledge of these pathological factors is limited, and treatment is unknown. This study aimed to find out the clinical predictors of EFS before OPU. Methods: In this study, 2342 cycles of 1148 cases that underwent OPU between January 2015 and November 2020 in two reproductive clinics were retrospectively enrolled. Ninety-one and 2251 cycles were classified as EFS (no cultivatable oocytes retrieved) and non-EFS (cultivatable oocytes retrieved), respectively. Results: The EFS and non-EFS incidence was 3.9% and 96.1%, respectively. The mean patient age in the EFS group was higher than that in the non-EFS group (40.3 ± 3.4 years vs. 37.9 ± 4.5 years, p < 0.001). Body mass indexes in the EFS and non-EFS groups were similar (21.7 ± 3.3 kg/m2 vs. 22.0 ± 3.5 kg/m2, p = 0.52). The anti-Müllerian hormone (AMH) levels, antral follicle count (AFC), and the number of follicles were lower in the EFS group than in the non-EFS group (1.0 ± 1.2 ng/mL vs. 2.7 ± 2.5 ng/mL, p < 0.001; 2.9 ± 2.2 vs. 8.5 ± 6.3, p < 0.001; 1.9 ± 1.4 vs. 6.0 ± 4.1, p < 0.001, respectively). However, unlike univariate analysis, logistic regression analysis showed no significant differences in age and AMH levels between the groups. The AFC and number of follicles were still significantly lower in the EFS than in the non-EFS group in multivariate analysis (odds ratio (OR), 1.301; 95% confidence interval (CI), 1.138–1.503; p < 0.05 and OR, 1.832; 95% CI, 1.488–2.3; p < 0.05, respectively). The EFS incidence rates for each follicle number just before OPU were 21.2%, 7.8%, 2.7%, and 1.2% with one, two, three, and four follicles, respectively. Not a single case of EFS was found among 410 cases with 10 or more follicles. Conclusions: The AFC and the number of follicles may be predictive of EFS.