The Effect of Early Rescue ICSI and Split IVF-ICSI in Preventing Low Fertilization Rate During the First ART Cycle: A Real-world Retrospective Cohort Study

Abstract BackgroundShort gamete coincubation in in vitro fertilization (IVF-S) combined with early rescue intracytoplasmic sperm injection (R-ICSI) and split IVF-ICSI insemination, are two methods to prevent unpredicted low or failed fertilization. This study aimed to determine the utility of IVF-S combined with R-ICSI and split IVF-ICSI during the first assisted reproductive technology (ART) cycle.Patients and methodsA single-center retrospective cohort study based on real-world data. Couples with a high risk of low IVF fertilization during the first ART cycle underwent IVF-S with R-ICSI (n=191) or split IVF-ICSI (n=775). Fertilization rate, embryo quality, and clinical outcomes were measured.ResultsAfter propensity score matching, we included 188 couples in the IVF-S with R-ICSI group as Group 1 and 720 in the split IVF-ICSI group as Group 2, with low IVF fertilization rates of 4.79% and 9.03%, respectively. Normal fertilization rates were similar in the two groups; however, Group1 had a higher multiple pronuclei rate (10.42% vs. 4.50%, P <0.001). The groups were similar for rates of high-quality embryos, blastocyst formation rate, embryo implantation, clinical pregnancy, miscarriage, loss to follow-up, and live birth. Low fertilization following IVF occurred in nine couples in Group 1 with 47 MII oocytes performed R-ICSI and 65 in Group 2 with 331 MII oocytes performed ICSI. Similar fertilization rate, embryo development, and clinical outcomes were noted in two groups with low fertilization.ConclusionsIVF-S with early R-ICSI and split IVF-ICSI were effective strategies in preventing IVF fertilization failure or low fertilization rate in couples with high-risk factors. IVF-S with early R-ICSI could become the preferred approach because of its advantages-fewer ICSI procedures, similar clinical pregnancy rate and live birth rate.