Termination of very early pregnancy by RU 486--an antiprogestational compound.

RU 486, a new antiprogestational compound, was given to 37 women seeking termination of pregnancy and with amenorrhea of 42 days or less. One patient was found at the second follow-up visit to have an extrauterine pregnancy. The patients received either 25 mg, 50 mg or 100 mg RU 486 twice daily for four days. All patients attended three follow-up visits, one, two and five to six weeks after the start of therapy. The start, duration and amount of bleeding as well as plasma progesterone, beta-hCG and cortisol concentrations were determined for each treatment day and at the follow-up visits. All patients but three started to bleed during treatment. Frequency of complete abortion was 61% (22 out of 36 patients). In only three patients was the pregnancy unaffected by treatment. The clinical efficacy of the treatment was not dose-dependent. Most of the patients experienced only minor side effects in terms of mild uterine pain, nausea and vomiting. However, two patients suffered from heavy bleeding requiring blood transfusion and curettage. In the patients with complete abortion, beta-hCG values decreased significantly but not until the first follow-up visit. The plasma progesterone also decreased. The decrease appeared earlier with the higher daily dose of RU 486. Cortisol concentrations increased during treatment with all 3 dosage regimens but the levels remained within the normal range. It is concluded that treatment with RU 486 may provide a novel therapy for "menstrual regulation" but the efficacy of the treatment needs to be improved to compete with alternatives such as vacuum aspiration.