Different Timings of Early Cumulus Cells Removal Have Different Multiple Pronuclei Rates in Human in Vitro Fertilization

Abstract

Background: Cumulus cells removal 4 h post-insemination has a significantly higher multiple pronuclei (MPN) rate than cumulus cells removal 20 h post-insemination. And, cumulus cells removal 6 h post-insemination has a significantly lower MPN rate than cumulus cells removal 20 h post-insemination. However, it remains unclear whether the different timings of early cumulus cells removal, such as the timings of 4, 5 and 6 h post-insemination, have significantly different MPN rates.Methods: This was a retrospective study. The included cycles were early cumulus cells removal cycles (n=752) at our center from January 2015 to August 2020. The included cycles were divided into two groups according to whether MPN exist (MPN=0% and MPN>0%). The patient and cycle stimulation characteristics of the two groups were compared. Binary logistic regression was performed to investigate the correlation between the timing of early cumulus cells removal and MPN. The cohort study was also performed to compare the patient characteristics, cycle stimulation characteristics, fertilization outcomes, and cultivation outcomes.Results: In the population of our study, the timing of early cumulus cells removal had a significant effect on the MPN. The cumulus cells removal ≤4 h post-insemination group had a high MPN rate, and the 5.5<time≤6 h group had a high fertilization failure rate. However, 2PN rate was not significantly different among the different timings of early cumulus cells removal. In addition, the ≤4 h post-insemination group had a high grade 1–2 embryo rate at day 3.Conclusion(s): Even if all the timings of cumulus cells removal are early, the different timings of early cumulus cells removal still have a significant effect on the MPN.