A randomized trial to compare two dosing intervals of misoprostol following mifepristone administration in second trimester medical abortion

Abstract

Simultaneous use of mifepristone and misoprostol for second trimester medical abortion is not as effective as the regimen using a 36-38 h dosing interval.

Short versus Standard Mifepristone and Misoprostol Regimen for Second- and Third-Trimester Termination of Pregnancy for Fetal Anomaly

“…One RCT reported an increase in chills and fever with mifepristone and immediate misoprostol when compared to a 36- to 38-hour interval [12]. All published studies reported no increase in adverse events, which is in agreement with our findings [13,14,15,16,17].…”

“…These intervals are similar to our standard regimen but are significantly shorter than the 16 h in our short regimen cohort, although the mifepristone-to-misoprostol interval of 12 h in the short regimen cohort is considerably less than that in the existing literature. Four RCTs reported percentage expulsion at 12 h post-misoprostol for mifepristone-to-misoprostol intervals <36 h, ranging from 73 to 82% compared to 36.3% in our short regimen cohort [12,13,14,16], although again the mifepristone-to-misoprostol intervals were greater than in our short regimen. Information regarding expulsion at 24 h was provided by 5 of the 6 studies examined and ranged from 91 to 98% [12,14,15,16,17], compared to 80% in our short and 91% in our standard regimen cohorts, respectively.…”

“…There are currently 4 randomised controlled trials (RCTs) and 2 observational studies (1 retrospective cohort study and 1 retrospective case series) assessing the effects of mifepristone-to-misoprostol dosing intervals <36 h for second-trimester termination of pregnancy in the context of fetal abnormality [12,13,14,15,16,17]. However, the retrospective case series also included 28 cases of intrauterine death, which were analysed as a subgroup [15].…”

“…Most studies used oral 200 mg mifepristone and vaginal 400 μg misoprostol [12,13,14,15,16], whilst 1 used oral misoprostol [15], broadly in line with our regimes (Appendix). Doses were halved for women with a previous caesarean.…”

“…Doses were halved for women with a previous caesarean. In the existing literature, the mifepristone-to-misoprostol interval ranges from immediate dosing to a 24-hour interval, and only 2 studies included mifepristone-to-misoprostol intervals below 14 h, which were comparable to our short regimen of ≤12 h [12,15]. …”