Retrospective cohort study comparing success of medical management of early pregnancy loss in pregnancies conceived with and without medical assistance.

Objective: To compare the success rates of medical management using a combined mifepristone and misoprostol protocol in cases of early pregnancy loss (EPL) between women who conceived without medical assistance and those who conceived through in vitro fertilization (IVF), after fresh or frozen embryo transfer, and evaluate for the predictive factors of success, time to first passage of tissue, and time to complete resolution of pregnancy.

Design: Retrospective cohort study.

Setting: University hospital.

Patient(s): Women who presented with EPL below 13 weeks of gestation between June 2013 and July 2021 who were managed medically with mifepristone 200 mg orally and misoprostol 800 mcg vaginally were included in the study.

Intervention(s): Medical management with mifepristone and misoprostol; conception without medical assistance vs. post-IVF, after fresh or frozen embryo transfer.

Main Outcome Measure(s): We evaluated overall success and performed subgroup analysis according to the mode of conception and compared fresh vs. frozen-thawed embryo transfers for IVF pregnancies. In all groups, we also calculated success according to gestational age and compared the time to first passage of tissue. The potential predictive factors of treatment success were analyzed. The side effects and complications of treatment were recorded.

Result(s): A total of 930 women were included in the study, 99 (11%) of whom achieved pregnancy after IVF. The overall success of medical treatment was 89% with no statistically significant difference according to the mode of conception (89% vs. 89%) or type of transfer (fresh 89% vs. frozen 89%). Only lower gestational age by sonography was independently predictive of treatment success, showing a negative regression coefficient of β = -0.333 and an odds ratio of 0.717. The mean time to first passage of tissue was 5.0 ± 2.1 hours. Altogether, 666 women (72%) showed pregnancy resolution on the day of medication administration, an additional 110 women at 1-week follow-up, and a further 74 women after ≥4 weeks on ultrasound.

Conclusion(s): Medical management of EPL with mifepristone and misoprostol is a highly successful treatment option that results in completed abortion in a timely fashion in both pregnancies conceived without medical assistance and those conceived after IVF.