Treatment of Early Pregnancy Loss With Mifepristone and Misoprostol Compared With Misoprostol Only

To compare the rates of treatment failure in cases of early pregnancy loss between mifepristone-misoprostol and misoprostol only.

This retrospective cohort study included patients who received medical treatment for early pregnancy loss between 2016 and 2023 at a single medical center. Patients returned for a follow-up ultrasonogram after 1 week and were treated again with misoprostol if needed. Finally, they were instructed to obtain an ultrasonogram after menstruation and to return for evaluation in case retained product of conception was suspected. We defined treatment failure as needing any surgical intervention because of retained product of conception, including cases when retained product of conception was diagnosed and treated after menstruation. In May 2022, we changed our protocol for treating early pregnancy loss from misoprostol to mifepristone and misoprostol. We compared the failure rate between patients who received mifepristone-misoprostol and those treated with misoprostol only.

A total of 999 patients were included: 224 in the mifepristone-misoprostol group and 775 in the misoprostol-only group. The rate of treatment failure was significantly lower in the mifepristone-misoprostol group compared with the misoprostol-only group (17.8% vs 25.1%, P =.002). After multivariant analysis was performed, the use of mifepristone and misoprostol was associated with a reduction of 34% in the odds ratio for treatment failure compared with misoprostol alone (adjusted odds ratio 0.661, 95% CI, 0.44-0.97, P =.038). In addition, prior vaginal delivery was associated with a lower risk for treatment failure, and increasing gestational age (according to ultrasonogram) was correlated with a higher risk for treatment failure.

The addition of mifepristone to misoprostol was associated with a significantly lower rate of treatment failure, including late surgical intervention for early pregnancy loss, compared with misoprostol alone.