Randomized study on the effect of adding oxytocin to ethacridine lactate or misoprostol for second-trimester termination of pregnancy.

To compare effectiveness of misoprostol and ethacridine lactate with or without oxytocin in second-trimester medical abortions. A randomized prospective study. A total of 388 women with genetic indications for termination of pregnancy at 13-24 weeks of gestation were recruited. Group I (n=85) were treated with extra-amniotic ethacridine lactate, 10 ml instilled per gestational week, to a maximum of 200 ml. Group II (n=93) were treated with misoprostol administered intravaginally (200 microg), followed by 100 microg of oral misoprostol 4 hourly for 24 h. Group III (n=102) were treated with a combination of ethacrine lactate and oxytocin. An initial dose of 6 mU/min oxytocin was given, followed by additional 6 mU/min doses every 20 min. Group IV (n=96) were treated with a combination of misoprostol and oxytocin administered in a similar way as in group III. The main outcome measures were time to induce abortion, side effects, and failure/success rates. The mean time to induce abortion was 14.2+/-3.6, 13.2+/-3.4, 10.8+/-2.6, and 9.9+/-2.4 h in groups I, II, III, and IV, respectively (p<0.001). Addition of oxytocin to ethacridine lactate did not decrease the risk of prolongation of induction beyond 24 h but use of oxytocin with misoprostol did reduce the risk of induction beyond 24 h (OR: 0.46, 95%CI: 0.21-1, p<0.05). The occurrence of minor side effects was similar in all groups. Addition of oxytocin to ethacridine lactate or misoprostol significantly decreases the length of time to induce abortion without supplementary side effects.