Early abortion with buccal versus sublingual misoprostol alone: a multicenter, randomized trial

To compare efficacy, safety/side effects and acceptability of buccal versus sublingual administration of a misoprostol-only regimen commonly used for early medical abortion.

We conducted a randomized trial at six clinics in two Latin American countries. We randomized women seeking early abortion to buccal or sublingual administration of three doses of misoprostol 800 mcg repeated every 3 h. At initial follow-up (7-14 days after misoprostol), we offered women without a complete abortion aspiration or additional misoprostol plus waiting 7 more days. The primary outcome was continuing pregnancy at initial follow-up. Secondary outcomes included continuing pregnancy at final follow-up, incomplete abortion, successful abortion, side effects, acceptability and complications. We analyzed all outcomes as intention to treat.

We enrolled 401 women and randomized 202 into the buccal arm and 199 into the sublingual arm. Continuing pregnancy at initial follow-up occurred in 11/201 (5.5%) and 2/189 (1.1%) women, respectively (p=.02). Additional misoprostol at follow-up increased success, defined as complete abortion, from 170/201 (84.6%) to 184/199 (92.5%) in the buccal arm and 165/189 (87.3%) to 177/189 (93.7%) in the sublingual arm. We found no differences by gestational age. Women reported similar acceptability and side effects across groups except for chills and fever, which women using sublingual misoprostol reported more frequently (p<.05).

Sublingual administration was superior to buccal administration in reducing continuing pregnancy risk after a three-dose regimen of 800 mcg misoprostol. Complete abortion rates were comparable across groups, and in both cases, additional misoprostol at follow-up increased success.

If the primary goal is to avoid continuing pregnancy, sublingual administration of misoprostol 800 mcg every 3 h for three doses should be recommended. If chills or fever are a concern and the primary goal is to avoid surgery, buccal administration may be preferable. For either route, additional misoprostol can be given for incomplete abortion or continuing pregnancy.