Termination of early pregnancy by a single dose of mifepristone (RU 486), a progesterone antagonist

Abstract

Mifepristone (RU 486) is a new steroid which is a progesterone antagonist and which is able to interrupt early pregnancy without any major side-effects. The purpose of our study was to evaluate the clinical effect of a single oral dose of 600 mg on early pregnancy. The study included 150 healthy women applying for a legal abortion with an amenorrhea of no more than 42 days. Pregnancy was confirmed by clinical and ultrasound examination and plasma HCG assessment. Success was assumed by repeating these exams on the eighth day. 131 patients had a complete abortion (87.3%), with a very few side-effects. Only two patients needed curettage for heavy bleeding. Mifepristone is able to terminate early pregnancy by an easy ambulatory method under medical supervision.

PIP: Mifepristone, a new steroid and progesterone antagonist, was administered to 150 women with amenorrhea of less than 42 days who were seeking abortions. A single dose of 600 mg was given to each woman to take orally at home in the evening. The clinical events that should occur were explained to the women and they were given a permanent emergency telephone number. Follow-up visits were scheduled on the 8th day, when clinical tests, ultrasound examinations, and blood sampling were performed. Success was assumed if vaginal bleeding occurred between days 3-8, ultrasonic examination confirmed uterine vacuity, and a decrease in plasma HCG level was observed. A total of 131 of the 150 women were considered to have had complete abortion. The remaining 19 women included 14 developing pregnancies, 2 curettages for heavy bleeding, and 1 extrauterine pregnancy. Daily amount and duration of bleeding were compared to abundant menstruation. Only 2 women reported heavy bleeding leading to curettage. Only 16 women had hemoglobin levels low enough to justify iron therapy. None needed a transfusion. Several other side effects were reported--uterine contractions and pelvic pain, transient asthenia, and slight nausea. All biological tests remained in the normal range. Having shown a success rate of 87.3% and with mild side effects, Mifepristone appears to be a simple and safe agent for termination of early pregnancy, and a good alternative to surgical abortion.