Comparative effectiveness of 200 mcg versus 400 mcg misoprostol dosing for medication abortion from 24 to 27 weeks'...

To assess efficacy and adverse outcomes of misoprostol 200 mcg versus 400 mcg every three hours buccal or vaginal for medication abortion (MAb) from 24 to 27 weeks' gestation.

This retrospective cohort study included MAbs from 24 0/7-27 0/7 weeks' gestation at Bellevue Hospital from 7/2022-6/2025. All patients received digoxin 2 mg intraamniotic injection and mifepristone 200 mg oral followed at 24-48 h by misoprostol 200 mcg or 400 mcg every three hours buccal or vaginal based on hospital policy at time of admission. The primary outcome was time from first misoprostol dose to placental expulsion. Secondary outcomes were procedural complications. Primary statistical analysis was performed with Fisher's exact and Wilcox rank-sum tests.

Of 55 patients, 27 (49%) received 200 mcg doses of misoprostol and 28 (51%) received 400 mcg doses of misoprostol. Median time to expulsion was 13 h in the 200 mcg group versus 9.5 h in the 400 mcg group (p = 0.144). More patients in the 200 mcg group versus the 400 mcg group had blood loss ≥ 500 mL (11.1% vs 0%, p = 0.11) and retained placenta at four hours (3.7% vs 0%, p = 0.49). No patients in either group had uterine rupture.

Misoprostol 200 mcg versus 400 mcg every three hours buccal or vaginal for MAb from 24 to 27 weeks' gestation had overall similar outcomes. Although this single site retrospective study is underpowered to significantly differentiate between the two regimens, we observe that 200 mcg dosing may be associated with higher risk of complications. Larger studies are needed to clarify optimal misoprostol dosing for 24-27 week MAb.

For medication abortion from 24 to 27 weeks' gestation, serial doses of misoprostol 200 mcg versus 400 mcg every three hours have similar rates of complications, though there is a signal that 200 mcg dosing may be associated with longer time to expulsion, higher blood loss, and more incidences of retained placenta.