Early versus late misoprostol administration after mifepristone for medical abortion.

Purpose: To evaluate the successful medical termination of pregnancy comparing two regimens: misoprostol 2 or 48 h after mifepristone administration.

Design: Prospective randomized study.

Setting: Department of Obstetrics and Gynecology.

Sample: One hundred pregnant women admitted for medical termination of pregnancy were enrolled; no pregnancies were over 55 days gestational age.

Methods: All subjects were randomly assigned for misoprostol administration either 2 or 48 h after mifepristone. All participants underwent transvaginal ultrasound examination for uterine contents 48 h and 3 weeks after mifepristone.

Main Outcome Measure: Procedure failure, defined as the presence of fetal heart activity, presence of a gestational sac, or a need for uterine curettage after misoprostol administration.

Results: Each group consisted of 50 women. Fetal heart activity was significantly more frequent after 48 h in the 2-h interval group (10/50) than in the 48-h interval group (0/50) (p = 0.002). Three weeks after misoprostol administration, fetal heart activity was present in 4/50 (8 %) in the 2-h interval group (p = 0.118) and none of the 48-h interval group. At 48 h residual tissue was present in 13/50 (26 %) and 5/50 (10 %) in the 2 and 48-h interval groups, respectively (p = 0.031); this was reduced to 12/50 (24 %) compared to 5/50 (10 %) in the two groups, respectively (p = 0.054) after 3 weeks.

Conclusions: Successful medical termination of pregnancy can be achieved using misoprostol administration 2 h after mifepristone in 76 % of cases. However, this regimen is not recommended as it is significantly inferior to the traditional 48-h interval regimen.