Background: Medical induction abortion is an acceptable alternative to surgical abortion for pregnancy termination. Misoprostol is an inexpensive PGE1 analogue that can be used easily and safely as a single agent for first- and second-trimester pregnancy termination. The objective of this study was to evaluate the efficacy of two different doses of vaginal misoprostol for pregnancy termination with gestational age up to 16 weeks.

Methods: This clinical trial included 100 pregnant women with gestational age up to 16 weeks requesting legal termination of pregnancy. The subjects were randomized in two equal groups, and received either 200 (group 1) or 400 µg (group 2) misoprostol vaginally every 6 hours with a maximum of four doses. Response to treatment was defined as complete or incomplete abortion within 48 hours after initial dose. Curettage was performed for patients with heavy bleeding or incomplete abortion. The abortion outcome and side-effects were assessed.

Results: The groups were similar in maternal age, gestational age, parity and obstetrical history and indication for pregnancy termination. The side effects in group 2 were significantly higher than in group 1 (P<0.05). There were no statistically significant differences between the two groups regarding completeness of the abortion and mean time to abortion induction.

Conclusions: In the termination of pregnancies up to 16 weeks, the 200 µg per dose regimen of misoprostol was as effective as the 400 µg regimen; however, side-effects were more common with the higher dose.