Higher rate of adverse events following abortion induced by mifepristone-misoprostol than procedurally

1. Mifepristone-misoprostol-induced abortions (IA) were associated with a higher risk of short-term adverse events than procedural IA in female patients up to 14 weeks of gestation.

2. Mifepristone-misoprostol IA was associated with a higher risk of an emergency department (ED) visit than procedural IA.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Procedural (surgical) IA is the conventional approach for pregnancy termination in the first trimester. Though, access to procedural IA can be challenging due to geographic barriers, local legislation, long wait times, and the need for self-referral. Mifepristone-misoprostol IA has been developed and introduced as an alternative. This oral medication has an efficacy of about 97% when used before 10 weeks gestation. However, there is a gap in knowledge as to understanding the short-term risk for adverse outcomes for this option. The relative safety and efficacy of mifepristone-misoprostol compared to procedural IA have not yet been evaluated in head-to-head trials. Overall, this study found that mifepristone-misoprostol IA resulted in more short-term adverse events than procedural IA, though the risk for serious adverse outcomes was very low. This study was limited by not assessing long-term outcomes, including future fertility and pregnancy outcomes. Nevertheless, these findings are significant, as they demonstrate that short-term adverse events are more likely to occur in mifepristone-misoprostol IA as compared to procedural IA.

Click to read the study in AIM

Relevant Reading: The War on Reproductive Health Care in the United States

In-Depth [retrospective cohort study]: This population-based retrospective cohort study included all women aged 15 to 49 years who had an IA up to 14 completed weeks’ gestation in Ontario, Canada between 2017 and 2020. Patients who were non-Ontario residents, women without continuous  Ontario Health Insurance Plan eligibility within two years of the index pregnancy date, women with missing information on rurality or neighborhood income, and women who had IA done while admitted to the hospital as an inpatient were excluded from the study. The primary outcome measured was a composite of any serious adverse events, comprising severe maternal morbidity, maternal end-organ damage, intensive care unit admission, or death. Outcomes in the primary analysis were assessed via logistic regression and propensity scores. Based on the primary analysis, serious adverse events occurred among 133 women after mifepristone-misoprostol IA (3.3 per 1000) versus 114 after procedural IA (1.8 per 1000) (Relative Risk [RR] 1.87, 95% Confidence Interval [CI] 1.44 to 2.43; Absolute Risk Difference [ARD] 1.5 per 1000, 95%CI, 0.9 to 2.2). The respective rates of any adverse event were 28.9 versus 12.4 per 1000 (RR 2.33, 95%CI, 2.11 to 2.57; ARD 16.5 per 1000, 95%CI 14.5 to 18.4). The respective rates of any adverse event were 31.2 versus 24.9 per 1000 (RR 1.25, 95%CI 1.04 to 1.51). In summary, this study demonstrates that mifepristone-misoprostol IA, compared to procedural IA, may lead to an increased risk of short-term adverse events.

Image: PD

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