Luteal phase treatment with mifepristone and misoprostol for fertility regulation

Abstract

Emergency contraception (EC) with 10 mg mifepristone can prevent pregnancy up to 5 days after a single act of unprotected intercourse. No methods have been shown to be effective when treatment is administered more than 5 days after a single unprotected act or after several unprotected acts. Therefore, we tested, among 699 Chinese women requesting EC and exposed to the risk of pregnancy described, the potential of 100 mg mifepristone followed 2 days later by 0.4 mg misoprostol orally, when administered in the luteal phase of the cycle. At the time of treatment urinary pregnancy test had to be negative. Despite treatment, 25 women (2.7%) became pregnant. Among women with treatment delayed more than 5 days, the pregnancy rate was related to the number of acts of intercourse before treatment, being 1.4% with one episode and increasing to 6.5% when the number of episodes was two or more (relative risk = 4.62, 95% CI: 1.06–20.18). Side effects within a week after treatment were mild, and most women (57.2%) had menstruation within 3 days as expected. An occasional treatment with mifepristone in combination with misoprostol could provide an option for preventing unwanted pregnancies in women who are late for EC.