Gestrinone Compared With Mifepristone for Emergency Contraception

Abstract

To compare the efficacy of gestrinone with that of mifepristone for emergency contraception. A randomized double-blind trial was conducted in five family-planning clinics in China. We randomly assigned 998 healthy women with regular menstrual cycles and negative urine pregnancy tests who were requesting emergency contraception up to 72 hours after unprotected coitus to receive single-dose 10 mg gestrinone (n=499) or 10 mg mifepristone (n=499). We monitored them to 7 days after the expected first day of their next menstrual period. The study was powered to detect a 5% failure rate between the two regimens. The treatment groups did not differ significantly; posttreatment pregnancy rates were 2.4% in the gestrinone group compared with 1.8% in the mifepristone group (P=.51). The majority of women menstruated the first day of expected menses, and groups did not differ regarding side effects. The effectiveness of 10 mg gestrinone is not significantly different from 10 mg mifepristone as an emergency contraceptive method. ISRCTN Register, isrctn.org, ISRCTN87842530. I.