Termination of pregnancy with reduced doses of mifepristone. World Health Organisation Task Force on Post-ovulatory Methods of Fertility Regulation.

OBJECTIVES

To compare the abortifacient efficacy and side effects of three doses of the antiprogestin mifepristone plus prostaglandin for termination of early pregnancy.

DESIGN

Randomised, double blind multicentre trial.

SETTING

11 departments of obstetrics and gynaecology and of family planning, mostly in university hospitals, in seven countries.

SUBJECTS: 1182 women with an early pregnancy (menstrual delay of 7-28 days) requesting abortion.

INTERVENTIONS: Single doses of 200 mg, 400 mg, or 600 mg mifepristone followed, 48 hours later, by vaginal pessary of 1 mg of the prostaglandin E1 analogue gemeprost.

MAIN OUTCOME MEASURES: Outcome of treatment; duration and subjective amount of menstrual bleeding; side effects and complications; and concentrations of haemoglobin.

RESULTS

Outcome was similar with the three doses of mifepristone. Of the 1151 women with known outcome, 95.5% had a complete abortion (364 (93.8%) of those given 200 mg mifepristone, 368 (94.1%) of those given 400 mg, and 367 (94.3%) of those given 600 mg), 3.7% had an incomplete abortion (14 (3.6%), 15 (3.8%), and 14 (3.6%)), 0.3% had a missed abortion (three (0.8%), one (0.3%), and none), and 0.4% had a continuing live pregnancy (two (0.5%), two (0.5%), and one (0.3%)). Of the 43 women who had incomplete abortion, 23 underwent emergency uterine curettage (usually for haemostatic purposes) and three of these women were given a blood transfusion. The numbers of reported complaints, bleeding patterns, and changes in blood pressure and haemoglobin concentrations were similar with the three treatments.

CONCLUSIONS

For termination of early pregnancy a single dose of 200 mg mifepristone is as effective as the currently recommended dose of 600 mg when used in combination with a vaginal pessary of 1 mg gemeprost.