Lower and extended dosage of misoprostol for cervical ripening in 1st trimester miscarriage (MISO200): A randomized...

To compare the efficacy of priming the uterine cervix before Manual Vaccum Aspiration (MVA) using 200 µg or 400 µg of vaginal misoprostol, inserted a mean time of 6 h before MVA in first trimester miscarriage.

Randomized, triple-blind, non-inferiority clinical trial. Patients between 18 and 50 years old, with a diagnosis of miscarriage, were eligible for the study. Patients were allocated to receive either 200 μg or 400 µg of misoprostol before the MVA. The primary outcome was the need to dilate the uterine cervix with mechanical dilators (Hegar dilators). As a secondary outcome, cervical dilatation ≥8 mm before the procedure was considered successful. A difference of <25% was considered as non-inferior.

Between December 21, 2016 and October 6, 2019, 269 women were screened. After screening, 105 and 106 women received 200 µg and 400 µg of misoprostol, respectively. Mechanical cervical dilatation was not necessary in 84.8% (95%CI 77% to 90%) and 96.2% (95%CI 91% to 99%), in the 200 µg and 400 µg groups, respectively [difference = 11.5% (95%CI 3.7% to 19.2%). Cervical dilatation of ≥8 mm was 52.4% (95%CI 42.9% to 61.7%) in the 200 µg misoprostol group, while in the 400 µg group was 71.7% (95%CI 62.5% to 79.4%) [difference = 19.3% (95%CI 6.5 to 32.2).

After a mean time of 6 h, 200 µg of vaginal misoprostol is not inferior to 400 µg of misoprostol for cervical priming before MVA, in first trimester miscarriage. This non-inferiority was not observed when the ≥8 mm criterion was considered.