Sublingual vs vaginal misoprostol for completion of first trimester missed abortion: a randomised controlled trial

The study aimed to compare the efficacy and safety of sublingual and vaginal misoprostol for termination of pregnancy in women with first trimester missed abortion.

A single-blind, parallel group, randomised clinical trial (ClinicalTrials.gov NCT02686840) was conducted in a university hospital between 1 February 2016 and 31 January 2017. All women who presented with first trimester missed abortion were invited to participate in the study and were randomised to one of two groups: one group received sublingual misoprostol in three doses of 800 μg every 4 h, while a second group received vaginal misoprostol in the same dosage regimen. The primary outcome of the study was the rate of complete abortion within 7 days after initiation of treatment.

The study included 200 women (100 in each arm). By day 7, successful complete abortion was significantly more frequent in the sublingual misoprostol group (71.4%) than in the vaginal misoprostol group (51.5%) (p = .006). By day 30, the rate of complete abortion was higher in the sublingual misoprostol group (90.6%) than in the vaginal misoprostol group (83.9%), but with no statistically significant difference (p = .164). The mean length of the induction-expulsion interval in the sublingual misoprostol group was significantly shorter compared with the vaginal misoprostol group (12.3 ± 3.1 h vs 16.4 ± 4.2 h, respectively; p = .001) and the sublingual misoprostol group had a smaller drop in haemoglobin level (p = .001). The side effects of misoprostol were significantly more frequent in the sublingual group compared with the vaginal group.

Sublingual misoprostol is more effective than vaginal misoprostol in completing first trimester missed abortion, with a shorter induction-expulsion time. Sublingual misoprostol is, however, associated with more side effects, such as unpleasant taste, gastrointestinal symptoms and fever, compared with vaginal misoprostol.