A randomized clinical trial of mifepristone (RU486) for induction of delayed menses: efficacy and acceptability

Mifepristone (RU486) should be useful for inducing menstrual bleeding in women with menses delayed up to 10 days. We evaluated this potential use for "menstrual regulation" in a randomized clinical trial with 16 women, half of whom received a single 600 mg dose and half of whom received a placebo. Four of eight women in each treatment group proved to be pregnant. Seven of eight who received mifepristone were not pregnant at two-week follow-up, in contrast to four of eight who received the placebo (p = 0.15). Mifepristone may hold promise for "menstrual regulation" for women who do not have access to medical confirmation of pregnancy or who choose not to have this determination made.Physicians in southern California conducted a double blind, randomized clinical trial (single oral 600 mg dose of RU-486 given to 8 women and a placebo to 8 other women) to determine its effectiveness in inducing delayed menstrual bleeding (i.e., menstrual regulation) and its acceptability. 4 women in each group were actually pregnant. 75% of the pregnant women in the RU-486 group experienced an abortion within 2 weeks while none of the pregnant women in the placebo group did. In other words, 88% of the RU-486 group were not pregnant 2 weeks after treatment compared with 50% of those in the placebo group (p=0.15). 1 woman in the placebo group whose initial beta human chorionic gonadotropin (hCG) level was 658 mIU/ml had a miscarriage later in the 1st trimester. Another woman in the RU-486 group, the only person enrolled twice in the study, experienced an abortion when her beta hCG level was 360 mIU/ml. The 2nd time her beta hCG level was 104 mIU/ml, however, and she did not experience an abortion. 2 of the nonpregnant women who received RU-486 started bleeding. The other 2 women had most likely not ovulated when they took RU-486. Side effects were similar for both groups, except for a more significant fall in hematocrit levels in the placebo group (p=0.03). 93.8% of all study subjects regardless of abortion or not thought RU-486 to be efficacious and preferred it to a surgical abortion even before they knew whether they would receive RU-486 or the placebo. 88.9% of the subjects who reported their feelings about abortion 4 weeks following treatment or the placebo claimed emotional relief on day 1. All expressed relief 2-4 weeks afterwards. RU-486 can be successfully used to regulate menstruation, especially in populations without access to medical are and pregnancy tests, and it may appeal to women who prefer not to know their status.