Testicular sperm characteristics in men with nonobstructive azoospermia and their impact on intracytoplasmic sperm injection outcome

Objective: To report fertilization and clinical pregnancy rates based on sperm characteristics at the time of intracytoplasmic sperm injection (ICSI) in men with nonobstructive azoospermia (NOA) following microdissection testicular sperm extraction (mTESE). Design: Retrospective cohort. Setting: Tertiary hospital. Patient(s): Men with NOA undergoing mTESE between 2013 and 2016 who had successful sperm retrieval and subsequent spermatozoa available for ICSI. Intervention(s): Sperm characteristic assessment. Main Outcome Measure(s): Fertilization and clinical pregnancy rates. Result(s): One hundred ninety-eight men with NOA and successful mTESE were included. The mean ages of the patients and their partners were 35 +/- 8 and 31 +/- 5 years, respectively. The overall fertilization rate was 44%, and the clinical pregnancy rate was 38%. The absence of twitching sperm motility and the presence of an acrosome defect were associated with decreased fertilization and clinical pregnancy rates on univariable analysis. On multivariable analysis, the presence of motility was associated with higher fertilization rates and greater odds of clinical pregnancy (odds ratio, 4.37; 95% confidence interval, 1.61-11.85). An abnormal acrosome was associated with reduced odds of pregnancy (odds ratio, 0.40; 95% confidence interval, 0.18-0.85). No specific anomaly or combination of sperm abnormalities precluded fertilization or clinical pregnancy with ICSI. Conclusion(s): To our knowledge, this is the first comprehensive study evaluating the importance of sperm characteristics and their impact on ICSI outcomes in men with NOA. The results suggest that no specific defect, including the use of nonmotile testicular spermatozoa, precluded a chance of clinical pregnancy. The study evaluated sperm characteristics at the time of ICSI injection; initial evaluation at the time of retrieval may differ significantly from that of spermatozoa selected for ICSI. (C) 2021 by American Society for Reproductive Medicine.