title: Contraceptive efficacy of testosterone-induced azoospermia and oligozoospermia in normal men.
abstract: OBJECTIVE
  To determine contraceptive efficacy of hormonally induced sperm suppression to severe oligozoospermia or azoospermia.
  
  
  METHODS
  Prospective, noncomparative contraceptive efficacy study.
  
  
  METHODS
  Multicenter study in 15 centers in nine countries.
  
  
  METHODS
  Three hundred ninety-nine normal, healthy, fertile men requesting a male contraceptive method.
  
  
  METHODS
  Weekly IM injection of 200 mg T enanthate.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: World Health Organization, Geneva, Switzerland.
mesh_terms: D000328:Adult; D000988:Antispermatogenic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D003267:Contraception / Q000379:methods; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009845:Oligospermia / Q000139:chemically induced*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012449:Safety; D013091:Spermatogenesis / Q000187:drug effects*; D013739:Testosterone / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000988:Antispermatogenic Agents; D008055:Lipids; D013739:Testosterone; C004648:testosterone enanthate