Comparison of conventional ICSI and rescue ICSI in patients without severe male factor and poor oocyte yield.

Objective: The aim of this study was to explore the effectivity and safety of early rescue intracytoplasmic sperm injection (R-ICSI) in patients with poor oocyte yield and non-severe male factor.

Methods: This study was a retrospective cohort analysis which included 604 conventional ICSI cycles and 116 early R-ICSI cycles at the Northwest Women's and Children's Hospital from February 2014 to December 2023. All patients were during their first assisted reproductive technologies (ART) cycle with 3-5 retrieved oocytes. The male partner had normal or mildly impaired sperm parameters. We compared the reproductive outcomes of conventional ICSI and early R-ICSI cycles in such patients.

Results: We observed that there were no significant differences in the MII (86.75 versus 85.09%; p = 0.329) and two pronuclei (2PN) (71.82 versus 72.02%; p = 0.934) rates between conventional intracytoplasmic sperm injection (ICSI) and early R-ICSI groups. Following conventional ICSI, a total multi-pronuclei (MPN) rate of 1.02% was achieved, which was significantly lower than that of 6.33% after early R-ICSI (p < 0.001). There were no significant differences in the D3 good quality embryo (51.80 versus 49.67%; p = 0.499), D3 available embryo (82.28 versus 78.38%; p = 0.112) and blastocyst formation (65.15 versus 68.69%; p = 0.494) rates between the two groups. We also observed that there were no significant differences in the pregnancy (55.45 versus 50.50%; p = 0.357), clinical pregnancy (52.00 versus 46.53%; p = 0.312), ongoing pregnancy (44.91 versus 39.60%; p = 0.324) and live birth (42.73 versus 37.62%; p = 0.339) rates between the two groups.

Conclusions: Despite the higher MPN rate, comparable outcomes can be achieved following early R-ICSI when compared to conventional ICSI for couples with non-severe male factor and poor oocyte yield.