Termination of early pregnancy using flexible, low-dose mifepristone-misoprostol regimens.

Background: Various regimens of mifepristone and misoprostol are used in medical abortion. We examined the effect of a change in protocol from a fixed mifepristone-misoprostol interval to a flexible one on the efficacy and uptake of medical abortion. In addition, risk factors of incomplete abortions were evaluated.

Study Design: Altogether, 1289 medical abortions were carried out between August 2000 and December 2002. Between August 2000 and August 2001, a fixed protocol of 200 mg of oral mifepristone followed by 0.4 mg of vaginally administered misoprostol 2 days later was used. From September 2001, a flexible dosing interval of 1, 2 or 3 days between mifepristone and misoprostol was adopted. At the same time, the upper limit of gestational age was increased from 56 to 63 days.

Results: The uptake of medical abortion increased during the study period and was 45.8% during the use of fixed protocol versus 54.6% during flexible protocol (p<.0001). The rates of complete abortion were 94.9% and 94.4% (n.s.), respectively. Continuing pregnancy was rare (0.7%). Among all subjects, a history of abortion was associated with a significantly lower rate of complete abortion (90.9 vs. 96.3%, p<.002). The other parameters analyzed (age, parity, duration of pregnancy, smoking, mifepristone-misoprostol interval) did not have a significant effect on the rate of complete abortion.

Conclusions: A flexible dosing protocol of mifepristone and misoprostol is effective; thus, its use is encouraged. Previous abortion is a significant risk factor of incomplete medical abortion. Thus, special attention should be paid to the follow-up of these women.