A randomized comparative study on vaginal administration of acetic acid-moistened versus dry misoprostol for mid-trimester pregnancy termination

Absorption and effectiveness of vaginally administered misoprostol tablets may vary according to the medium in which it is placed. This study was directed to compare the outcomes of vaginal administrations of acetic acid-moistened misoprostol tablets with those of dry tablets for induction of second-trimester abortion. A randomized comparative trial where 322 women at 13-20 weeks gestation, requiring medical abortion, were randomly assigned to vaginal administration of either acetic acid-moistened or dry misoprostol tablets with a dose schedule of 400 mu g three-hourly, up to a maximum five doses over 24 h. The same doses were repeated for another 24 h in nonresponders. Primary outcome measure was complete abortion rate at 24 and 48 h, and the secondary outcome measures were induction-abortion interval, failure rate and side effects. A difference of 15% in success rates at 24 h was used to calculate the sample size required with a power of 0.8 at the 5% significance level. No statistically significant differences in the complete abortion rates were observed at 24 h (70.95 vs. 68.71%, P = 0.675) and at 48 h (86.49 vs. 84.35%, P = 0.604) when both groups were compared. The difference in mean induction-abortion interval was also statistically insignificant between the groups (12.5 +/- A 1.6 vs. 12.8 +/- A 1.5 h, P = 0.97). Other outcome measures were also comparable in both groups. Moistening misoprostol tablets with 5% acetic acid before vaginal application creates no difference in outcomes when compared with those after the vaginal application of dry tablets for the termination of second-trimester pregnancy.