A comparison of 600 and 200 mg mifepristone prior to second trimester abortion with the prostaglandin misoprostol

OBJECTIVE: To compare the use of 600 and 200 mg mifepristone prior to second trimester termination of pregnancy with the prostaglandin misoprostol. DESIGN: A randomised study. SETTING: A Scottish teaching hospital. PARTICIPANTS: Seventy women undergoing legal induced abortion between 13 and 20 weeks of gestation. INTERVENTION: Administration of either 600 or 200 mg mifepristone 36 to 48 hours prior to prostaglandin. MAIN OUTCOME MEASURE: Induction-abortion interval. RESULTS: The geometric mean induction abortion interval was 6.9 (95% CI 5.8-8.4) h and 6.9 (95% CI 5.8-8.2) h in the 600 and 200 mg groups, respectively (no significant difference). The median dose of misoprostol was 1600 micrograms (three doses) in each group. Analgesic requirements and prostaglandin-related side effects were similar between groups. Overall, 11.4% of women required surgical evacuation of the uterus as a result of retained placenta. CONCLUSIONS: The dose of mifepristone used in second trimester abortion can be reduced from 600 to 200 mg.