Contraceptive efficacy of testosterone-induced azoospermia and oligozoospermia in normal men.

OBJECTIVE

To determine contraceptive efficacy of hormonally induced sperm suppression to severe oligozoospermia or azoospermia.

DESIGN

Prospective, noncomparative contraceptive efficacy study.

SETTING

Multicenter study in 15 centers in nine countries.

PARTICIPANTS

Three hundred ninety-nine normal, healthy, fertile men requesting a male contraceptive method.

INTERVENTION

Weekly IM injection of 200 mg T enanthate.

MAIN OUTCOME MEASURE

Incidence of pregnancies in efficacy when couples relied on T injections alone for contraception.

RESULTS

Four pregnancies occurred during 49.5 person-years involving men with oligozoospermia (0.1 to 3 x 10(6)/mL) and none during 230.4 person-years in azoospermic men: pregnancy rates 8.1 (95 percent confidence interval [CI] 2.2 to 20.7) and 0.0 (95 percent CI, 0.0 to 1.6) per 100 person-years, respectively, or 1.4 (95 percent CI, 0.4 to 3.7) per 100 person-years for oligozoospermia and azoospermia (O to 3 x 10(6)/mL) combined. Pregnancy rates were related to sperm concentration. Inadequate suppression of spermatogenesis occurred in eight men and escape from suppression occurred in four. Discontinuations were due to personal reasons (50 men, cumulative annual life-table rate 12.2 percent [95 percent CI, 9.1 percent to 16.1 percent]) and dislike of the injection schedule (21 men, 5.1 percent [95 percent CI, 3.2 percent to 7.9 percent]). Thirty-five men discontinued for medical reasons (9.4 percent [95 percent CI, 6.7 percent to 13.2 percent]), with 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 (< or = 3 x 10(6)/mL) induced by weekly T enanthate injections results in sustained, reversible contraception with good efficacy and minimal short-term side effects. New hormonal regimens with more convenient delivery and improved spermatogenic suppression would provide practical male contraception.