Two mifepristone doses and two intervals of misoprostol administration for termination of early pregnancy: a randomised factorial controlled equivalence trial*

Abstract

Objective To compare the efficacy of 100 mg and 200 mg of mifepristone and 24-and 48-hour intervals to administration of 800mg vaginal misoprostol for termination of early pregnancy.Design Placebo-controlled, randomized, equivalence trial, stratified by centre.Setting 13 departments of obstetrics and gynecology in nine countries.Population 2181 women with 63 days or less gestation requesting medical abortion.Methods Two-sided 95% CI for the risk differences of failure to complete abortion were calculated and compared with 5% equivalence margin between two doses of mifepristone and two intervals to misoprostol administration. Proportions of women with adverse effects were compared between the regimens using standard testes for proportions.Outcome measures Rates of complete abortion without surgical intervention and adverse effects associated with the regimens.Results Efficacy outcome was analysed for 2126 women (97.5%) excluding 55 lost to follow up. Both mifepristone doses were found to be similar in efficacy. The rate of complete abortion was 92.0% for women assigned 100 mg of mifepristone and 93.2% for women assigned 200 mg of mifepristone (difference 1.2%, 95% CI: -1.0 to 3.5). Equivalence was also evident for the two intervals of administration: the rate of complete abortion was 93.5% for 24-hour interval and 91.7% for the 48-hour interval (difference -1.8%, 95% CI: -4.0 to 0.5). Interaction between doses and interval to misoprostol administration was not significant (P = 0.92). Adverse effects related to treatments did not differ between the groups.Conclusions Both the 100 and 200 mg doses of mifepristone and the 24-and 48-hour intervals have a similar efficacy to achieve complete abortion in early pregnancy when mifepristone is followed by 800 micrograms of vaginally administered misoprostol.

A Simple Procedure for Termination of Pregnancy in the Late First Trimester with Mifeprostone and Misoprostol

“…When judged by the efficacy of medical termination in the early part of the first trimester our results are comparable with previous publications [6] [17] [18]. When compared with previous studies of late first semester medical TOPs, the overall complete abortion rate was close to the success rates reported in previous studies [13] [14] [19].…”

One- and two-day mifepristone-misoprostol intervals for second trimester termination of pregnancy between 13 and 16 weeks of gestation

“…The action of mifepristone on the pregnant uterus is believed to take effect over 24 hours after ingestion of the medication [11], and with a more pronounced effect after 36-48 hours [12]. A randomized controlled trial into termination of first trimester pregnancy claims that the interval between mifepristone and vaginally administered misoprostol can be reduced from 48 to 24 hours without loss of efficacy [13].…”

Misoprostol dose and route after mifepristone for early medical abortion: a randomised controlled noninferiority trial

“…8 The 24 hours interval was also found to be more practical, so in this study we used the 24-hours administration interval between mifepristone and misoprostol.…”