To compare one- and two-day intervals in second trimester medical termination of pregnancy(TOP).

This open randomized trial included 227 women undergoing TOP between gestational weeks 13-24. Mifepristone(200 mg) was followed by misoprostol(400 μg) after one day [(17-28) h] or two days [(41-45) h], as 1 d group (n=120) and 2 d group (n=107). The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Qingdao Ninth People's Hospital. Two groups were compared abortion time, after curettage abortion rate, adverse reactions and complications; and examines the history of suffering from pregnancy and pregnancy influence of time on TOP.

In intention-to-treat analysis, the median induction-to-abortion interval was 1 h longer in the 1 d group(8.5 h vs. 7.2 h, P=0.038), but in per-protocol analysis, the rate of surgical evacuation was higher in the 2 d group [25%(30/115) vs. 37%(40/112); 95% confidence interval 0.3-24.1, P=0.044]. A subgroup analysis showed that the median induction-to-abortion interval was 3 h longer in the 1 d group, amongst women without previous vaginal deliveries(10.1 h vs. 7.6 h, P=0.013) and when gestation exceeded 16 weeks(10.8 h vs. 7.2 h, P=0.024).

Both one- and two-day dosing intervals seem to be suitable for second trimester medical TOP, but women with no previous deliveries and those whose gestation exceeds 16 weeks may benefit from the longer interval. However, evaluated on the basis of surgical evacuation, the one-day interval could be supported as an option for second trimester medical TOP. Effective use of both one- and two-day dosing intervals is important when optimizing clinical service.