Misoprostol alone is associated with high rate of successful first-trimester abortion

Reference

Raymond EG, Harrison MS, Weaver MA. Efficacy of misoprostol alone for first-trimester medical abortion. Obstet Gynecol 2019;133(1):137-147.

Synopsis

This paper is an updated meta-analysis of misoprostol alone for abortion in the first trimester of pregnancy. Selected studies included women with viable pregnancies of variable gestational age limit, ranging from 42 dyas to 98 days, nearly universally determined by ultrasonography. The meta-analysis included 42 studies with 53 study groups and 13,573 women. A total of 12,829 were included in the analysis after the exclusion of 744 women who were lost before outcomes were known (5%). There were multiple regimens, with dosing from 200 mg to 800 mg. The most common dose was 800 mg (n = 40 groups, 92% of women); the most common route of administration was vaginal (n = 38 groups, 81% of women). Most women were instructed to take no more than 3 doses within 48 hours. After one or more required doses, women in 35 groups (38% of women) could use additional doses, up to a maximum of 6 doses over 14 days. Across all studies the meta-analytic estimate of the rate of women who underwent subsequent surgical evacuation was 22.0% (95% CI 18.8 - 25.5). The authors analyzed heterogeneity across studies and identified several factors associated with higher risk of surgical evacuation. They demonstrated a linear trend (P ≤ .001) with the 800 mg dosing being approximately one fourth the risk of the 200 mg dosing. Oral administration was associated with a threefold higher risk compared with vaginal, buccal, or sublingual administration. Surgery was less common when tablets were moistened before vaginal insertion (odds ratio [OR] 0.46; 0.35 - 0.60). Surgery also declined with allowed number of doses, duration of dosing (linear trend P