RANDOMIZED CONTROLLED TRIAL OF LEVONORGESTREL VERSUS THE YUZPE REGIMEN OF COMBINED ORAL-CONTRACEPTIVES FOR EMERGENCY CONTRACEPTION

Background A previous randomised study suggested that the progestagen, levonorgestrel, given alone in two separate doses each of 0.75 mg cau sed nausea and vomiting in fewer women and might be more effective tha n the Yuzpe regimen of combined oral contraceptives for emergency cont raception, although the difference was not significant. We compared th ese two regimens when started within 72 h of unprotected coitus. Metho ds We enrolled in the double-blind, randomised trial 1998 women at 21 centres worldwide. Women with regular menses, not using hormonal contr aception, and requesting emergency contraception after one unprotected coitus, received levonorgestrel (0.75 mg, repeated 12 h later) or the Yuzpe regimen (ethinyloestradiol 100 mu g plus levonorgestrel 0.5 mg, repeated 12 h later). Findings Outcome was unknown for 43 women (25 a ssigned levonorgestrel, 18 assigned Yuzpe regimen). Among the remainin g 1955 women, the crude pregnancy rate was 1.1% (11/976) in the levono rgestrel group compared with 3.2% (31/979) in the Yuzpe regimen group. The crude relative risk of pregnancy for levonorgestrel compared with the Yuzpe regimen was 0.36 (95% CI 0.18-0.70). The proportion of preg nancies prevented (compared with the expected number without treatment ) was 85% (74-93) with the levonorgestrel regimen and 57% (39-71) with the Yuzpe regimen. Nausea (23.1 vs 50.5%) and vomiting (5.6 vs 18.8%) were significantly less frequent with the levonorgestrel regimen than with the Yuzpe regimen (p<0.01). The efficacy of both treatments decl ined with increasing time since unprotected coitus (p=0.01). Interpret ation The levonorgestrel regimen was better tolerated and more effecti ve than the current standard in hormonal emergency contraception. With either regimen, the earlier the treatment is given, the more effectiv e it seems to be.