Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis.
Level 1 - systematic review of randomized trials
Individual participant data meta-analysis of 30 prospective clinical studies
PubMed 16650651 · doi:10.1016/S0140-6736(06)68614-5
What was done
An integrated multivariate time-to-event analysis was conducted on individual participant data from 30 prospective studies published between 1990 and 2005 evaluating androgen or androgen-progestagen regimens for male contraception. The cohort included 1,549 healthy eugonadal men aged 18–51 years (965 White, 535 Asian, 49 other origins) accounting for 1,283.5 man-years of treatment and 705 man-years of post-treatment recovery. Monthly sperm concentrations were monitored until recovery. The primary outcome was time to achieve a sperm concentration of 20 million per mL, analyzed with Kaplan-Meier and Cox multivariate models.
What was found
Median times to recover to sperm concentrations of 20, 10, and 3 million per mL were 3.4 months (95% CI 3.2–3.5), 3.0 months (95% CI 2.9–3.1), and 2.5 months (95% CI 2.4–2.7), respectively. The probability of recovery to 20 million per mL was 67% (95% CI 61–72) by 6 months, 90% (85–93) by 12 months, 96% (92–98) by 16 months, and 100% by 24 months. Multivariate analysis identified faster recovery with older age, Asian ethnicity, shorter treatment duration, shorter-acting testosterone formulations, higher baseline sperm concentration, faster suppression, and lower baseline luteinising hormone.
Why it matters
This analysis confirms that spermatogenesis suppression from male hormonal contraception is fully reversible in 100% of participants within a predictable timeframe, addressing a fundamental safety question for contraceptive development.
Limits
The primary outcome relied on a surrogate threshold of sperm concentration (20 million/mL) rather than confirmed pregnancy or live birth rates. Ethnic diversity was limited mainly to White and Chinese men, and regimens varied across the 30 source studies.
Cited by
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- supports Following testosterone replacement therapy cessation, recovery of sperm count and fertility can take up to two years.