Chicago—In men with nonobstructive azoospermia, frozen and fresh testicular sperm offer similar fertilization and pregnancy rates, according to the authors of a meta-analysis who say it is the first such study to specifically address the fresh-versus-frozen debate in this population.
Researchers say the findings suggest that attempts to coordinate the timing of sperm acquisition for intracytoplasmic sperm injection (ICSI) to the in vitro fertilization (IVF) cycle may be unnecessary. Use of cryopreserved sperm also allows clinicians to know whether sperm is available for artificial reproduction.
Study authors from the University of Illinois, Chicago and Stanford University, Palo Alto, CA reviewed the available data on nonobstructive azoospermia and ICSI outcomes to determine if frozen sperm is associated with decreased fertilization and pregnancy rates. Inclusion criteria included four levels of data: men with nonobstructive azoospermia, fresh and frozen testicular sperm data, pregnancy as defined by fetal heartbeat, and fertilization per oocyte injected. The authors identified a total of 224 studies, 11 of which met criteria for clinical pregnancy rate and 10 of which met criteria for fertilization rate.
Twenty-eight percent (84 of 299) of ICSI cycles of frozen-thawed testicular sperm resulted in clinical pregnancy compared with 29% (79 of 275) of ICSI cycles of fresh sperm (relative risk of 1.00 [95% CI: 0.75, 1.33]). Oocyte fertilization rates were also similar for frozen-thawed sperm compared with fresh sperm: 54% (1,490 of 2,757) versus 53% (1,422 of 2,687) (RR of 0.97 [95% CI: 0.92, 1.02]).