CONTRACEPTIVE EFFICACY OF TESTOSTERONE-INDUCED AZOOSPERMIA AND OLIGOZOOSPERMIA IN NORMAL MEN

Objective: To determine contraceptive efficacy of hormonally induced s perm suppression to severe oligozoospermia or azoospermia. Design: Pro spective, noncomparative contraceptive efficacy study. Setting: Multic enter study in 15 centers in nine countries. Participants: Three hundr ed ninety-nine normal, healthy, fertile men requesting a male contrace ptive method. Intervention: Weekly IM injection of 200 mg T enanthate. Main Outcome Measure: Incidence of pregnancies in efficacy when coupl es relied on T injections alone for contraception. Results: Four pregn ancies occurred during 49.5 person-years involving men with oligozoosp ermia (0.1 to 3 x 10(6)/mL) and none during 230.4 person-years in azoo spermic men: pregnancy rates 8.1 (95% confidence interval [CI] 2.2 to 20.7) and 0.0 (95% CI, 0.0 to 1.6) per 100 person-years, respectively, or 1.4 (95% CI, 0.4 to 3.7) per 100 person-years for oligozoospermia and azoospermia (0 to 3 x 10(6)/mL) combined. Pregnancy rates were rel ated to sperm concentration. Inadequate suppression of spermatogenesis occurred in eight men and escape from suppression occurred in four. D iscontinuations were due to personal reasons (50 men, cumulative annua l Life-table rate 12.2% [95% CI, 9.1% to 16.1%]) and dislike of the in jection schedule (21 men, 5.1% [95% CI, 3.2% to 7.9%]). Thirty-five me n discontinued for medical reasons (9.4% [95% CI, 6.7% to 13.2%]), wit h no serious treatment-related side effects. After stopping injections , sperm output recovered; additionally, fertility was demonstrated in 33 couples. Conclusion: Suppression of spermatogenesis to azoospermia or severe oligozoospermia (less than or equal to 3 x 10(6)/mL) induced by weekly T enanthate injections results in sustained, reversible con traception with good efficacy and minimal short-term side effects. New hormonal regimens with more convenient delivery and improved spermato genic suppression would provide practical male contraception.