Sublingual misoprostol 100 microgram versus 200 microgram for second trimester abortion: a randomised trial

To compare the efficacy of repeated doses of 100 microg vs. 200 microg misoprostol given sublingually for induction of second trimester abortion.

One hundred and sixty-two women at 15-22 weeks' gestation were randomized to receive every 2 h either 100 microg (group 1; n = 81) or 200 microg (group 2; n = 81) misoprostol sublingually. The primary outcome measure was the abortion rate within 24 h. The secondary outcome measures were the induction-abortion interval, the total misoprostol dose required, and side effects of the regimen.

There was no significant difference between the two groups with regard to the abortion rates within 12 h (43.2% in group 1 vs. 48.1% in group 2; p = 0.52; relative risk [RR]: 0.81; 95% confidence interval [CI]: 0.4-1.5) and 24 h (92.6% in group 1 vs. 91.4% in group 2; p = 0.77; RR: 1.11; 95% CI: 0.37-3.6). The induction-abortion intervals in the two groups were of similar length (885 minutes in group 1 vs. 912 minutes in group 2; p = 0.72). When the total dose of misoprostol was compared between the two groups, women belonging to group 2 on average had received significantly more misoprostol than those in group 1 (1274 +/- 592 microg [7 +/- 3 doses] vs. 614 +/- 432 microg [6 +/- 4 doses], respectively; p = 0.000).

Sublingual administration of repeated doses of 100 microg misoprostol for abortion induction appears to be equally effective to that of repeated doses of 200 microg.