Intracytoplasmic sperm injection versus conventional in-vitro fertilisation for couples with infertility with non-severe male factor: a multicentre, open-label, randomised controlled trial.

BACKGROUND:Introduced in 1992, intracytoplasmic sperm injection (ICSI) was initially indicated for severe male infertility; however, its use has since been expanded to non-severe male infertility. We aimed to compare the efficacy and safety of ICSI versus conventional in-vitro fertilisation (IVF) in couples with infertility with non-severe male factor. METHODS:We conducted an investigator-initiated, multicentre, open-label, randomised controlled trial in ten reproductive medicine centres across China. Couples with infertility with non-severe male factor without a history of poor fertilisation were randomly assigned (1:1) to undergo either ICSI or conventional IVF. The primary outcome was live birth after first embryo transfer. We performed the primary analysis in the intention-to-treat population using log-binomial regression models for categorical outcomes or linear regression models for continuous outcomes, adjusting for centre. This trial is registered with Clinicaltrials.gov, NCT03298633, and is completed. FINDINGS:Between April 4, 2018, and Nov 15, 2021, 3879 couples were screened, of whom 2387 (61·5%) couples were randomly assigned (1184 [49·6%] to the ICSI group and 1203 [50·4%] to the conventional IVF group). After excluding couples who were ineligible, randomised twice, or withdrew consent, 1154 (97·5%) in the ICSI group and 1175 (97·7%) in the conventional IVF group were included in the primary analysis. Live birth after first embryo transfer occurred in 390 (33·8%) couples in the ICSI group and in 430 (36·6%) couples in the conventional IVF group (adjusted risk ratio [RR] 0·92 [95% CI 0·83-1·03]; p=0·16). Two (0·2%) neonatal deaths were reported in the ICSI group and one (0·1%) in the conventional IVF group. INTERPRETATION:In couples with infertility with non-severe male factor, ICSI did not improve live birth rate compared with conventional IVF. Given that ICSI is an invasive procedure associated with additional costs and potential increased risks to offspring health, routine use is not recommended in this population. FUNDING:National Natural Science Foundation of China, National Key Research and Development Program, Beijing Municipal Science & Technology Commission, and Peking University Third Hospital.