Cumulative live birth rates in donor oocyte ICSI cycles are not improved by magnetic-activated cell sorting sperm selection

RESEARCH QUESTION: Does magnetic-activated cell sorting (MACS) for sperm selection increase cumulative live birth rates (CLBR) or improve clinical parameters of reproductive success in couples undergoing intracytoplasmic sperm injection (ICSI) with donor oocytes? DESIGN: Retrospective multicentre observational study including data compiled from unselected couples who underwent ICSI cycles with donated oocytes in 15 Spanish IVIRMA fertility clinics (January 2008 to February 2020). Patients were divided into reference (standard semen processing, n = 40,157) and MACS (additional sperm selection step by MACS, n = 1,240) groups. CLBR were plotted on Kaplan-Meier curves and compared using the Mantel-Cox test. Proportions were compared with a generalized estimating equation model, and results were adjusted to clinically relevant variables. RESULTS: The MACS group showed a 27.1% CLBR after one embryo was transferred and 81.6% after four; the reference group had CLBR of 19.6% and 78.5%, respectively. CLBR in the MACS group was 4.2% after five oocytes were used and 75.5% after 15; for the reference group, CLBR were 7.8% and 78.3%, respectively. Kaplan-Meier curves showed statistically significant differences in CLBR per number of embryos transferred and per number of donated metaphase II oocytes between the two groups (both P