Interruption of early pregnancy by an anti-progestational compound, RU 486.

RU 38-486 (17 beta-hydroxy-11 beta-(4-dimethylaminophenyl)-17 alpha-(1-propynyl)estra-4,9-dien-3-one), an antiprogestational compound, was given to 33 women seeking termination of pregnancy. The patients were divided into two groups, 24 patients in group I with amenorrhoea up to 7 6/7 wk = 55 days, and 9 patients in group II with 8-10 wk amenorrhoea. The patients received 200 mg orally per day for 4 days. The start, duration and amount of bleeding were determined for 14 days. beta-HCG, plasma progesterone, estradiol and cortisol were determined at day 0 and day 7. All patients started to bleed during treatment. The frequency of complete abortion was 79% (19 out of 24 patients) in group I. In group II 33% (3 out of 9 patients) had a complete abortion. Most of the patients experienced only minor side-effects in terms of mild uterine pain and bleeding as in a spontaneous abortion. However, 2 patients in group II with 8 and 9 2/7 wk amenorrhoea suffered from heavy bleeding, requiring blood transfusion and curettage. In the patients with complete abortion, beta-HCG, estradiol and progesterone decreased significantly within 1 week. Cortisol concentrations remained within the normal range at day 0 and day 7. Treatment with RU 486 provides an acceptable method of early abortion, especially in women who refuse operative treatment and prefer a 'spontaneous abortion'. In 22 women RU 486 was administered from day 24 to day 27 of the menstrual cycle as a late 'morning-after pill' in the same dosage. All women except one started to bleed before day 28 and observed a normal menstrual period. One woman stayed amenorrhoeic for 2 months; she was not pregnant but apparently had an anovulatory cycle with a low progesterone level.