Preliminary results with the antiprogestational compound RU-486 (mifepristone) for interruption of early pregnancy.

RU-486 (mifepristone) (Roussel-Uclaf, Paris, France) is an antiprogesterone that acts through a competitive binding at the site of the progesterone and cortisol receptor. It induced a complete expulsion in 29 (83%) of 35 patients with an unwanted pregnancy with up to 55 days of amenorrhea. A complete expulsion occurred in 17 (89%) of the 19 nulliparous women, and no serious side effects were seen. However, our results were less successful in ine patients with a more advanced pregnancy (between 8 and 10 weeks). In this group, only three complete expulsions were seen.