Influencing factors of polyspermy during in vitro fertilization with antagonist protocol

Objective: To explore the influencing factors of polyspermy in long-term fertilization during in vitro fertilization (IVF) with antagonist protocol. Methods: This was a retrospective case-control study. Patients with secondary infertility undergoing assisted reproductive treatment in the Department of Reproductive Medicine of Maternity a Child Care Center of Qinhuangdao between January 2020 and May 2023 were selected. Five hundred and thirty-six ovulation induction cycles with antagonist protocol were included and divided into the control group (multiple pronuclei(PN) rate= 0%, n=347) and the polyspermy group (multiple PN: 2PN >= 20%, n=189) according to the incidence of polyspermy. The general data and embryonic development of the two groups were statistically analyzed. Results: There were no statistically significant differences in male age, infertile duration, body mass index (BMI), basal follicle-stimulating hormone (FSH) level, number of follicles with a diameter of >= 16mm, total dose of gonadotropin (Gn), total Gn stimulation days, and sperm concentration between the two groups (all P>0.05). Similarily no statistically significant differences in female age, levels of estradiol (E2), LH, and progesterone (P) and number of follicles with a diameter of >= 14 mm on human chorionic gonadotropin (hCG) injection day, the total number of eggs retrieved, amount of Gn/egg, and fertilization concentration (sperms/egg) were observed between the two groups (all P<0.05). The results of logistic binary regression analysis showed that the level of LH on hCG injection day was an independent risk factor for the incidence of polyspermy in antagonist protocol. Conclusion: In the process of ovulation induction in antagonist protocol, the appropriate addition of LH can improve embryo outcomes.