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.
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]).
Findings were reported at the AUA annual meeting in San Diego and is currently in press in Fertility and Sterility.
“What we’re able to show here is that in terms of clinical pregnancy rate and fertilization outcomes, there is no statistical difference [between fresh and frozen sperm], meaning that cryopreservation may be a reasonable option,” said first author Samuel Ohlander, MD, a urology resident at the University of Illinois working with Craig Niederberger, MD, and colleagues.
Clinical practice changing?
Previous studies that included both obstructive azoospermia and nonobstructive have shown similar findings, Dr. Ohlander told Urology Times. Nevertheless, in clinical practice, coordinating the timing of sperm acquisition to the IVF cycle still appears to be common. When the AUA session moderator asked how many physicians in the room no longer make attempts to time sperm acquisition to the IVF cycle for nonobstructive azoospermia, only a handful of hands went up. When asked how many only coordinate the timing with fresh sperm, a few additional hands rose.
Risk of cryodestruction with freezing remains a concern, especially in men who are severely hypospermatogenic, Dr. Ohlander noted.
“The take-home message,” he concluded, “is that it’s a reasonable option to talk to these people about the possibility of cryopreservation to save them from undergoing a potentially unnecessary procedure.”UT
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