TIMING OF SERIOUS ADVERSE EVENTS FOLLOWING MIFEPRISTONE ABORTION IN US COMMERCIAL AND MEDICAID POPULATIONS

Author(s)

Onur Baser, MA, MS, PhD1, Precious Nchekwube, MPH2, Yaas Azmoudeh, MPH3, Wanlin Guo, MS2;
1City University of New York (CUNY), Graduate School of Public Health, New York, NY, USA, 2Columbia Data Analytics, New York, NY, USA, 3Rowan University, Cooper Medical School, Camden, NJ, USA
OBJECTIVES: We generated risk-adjusted estimates of adverse events (AEs) following mifepristone abortion suitable for comparison with clinical trial data, to inform evidence-based policy development
METHODS: This retrospective cohort study comprised approximately 172 million commercially insured patients and 60 million Medicaid-insured patients from Kythera Labs Commercial and Medicaid claims between 01JAN2017-15NOV2025. Clinically important AEs, including sepsis, infection, transfusion, hemorrhage, hospitalization, ectopic pregnancy, and life-threatening AEs (repeated surgical abortion, emergency department [ED] visits occurring within 0-15, 16-30, and 31-45 days of abortion) were evaluated. AEs were categorized as major if they required hospital admission and minor if they did not. Odds ratios (ORs) and predicted probabilities were estimated across combinations of age, comorbidities, and socioeconomic status (SES), and race/ethnicity.
RESULTS: Women with medical abortions and ≥1 clinically important AE (commercial: 7.45% [16,654/223,403]; Medicaid: 6.44% [3872/60,163]) were included. In the commercial population, 60.36% of the first AEs occurred within 15 days, 23.25% within 16-30 days, and 16.39% occurred within 31-45 days. In the Medicaid population, 60.80% of first AEs occurred within 15 days, 23.11% within 16-30 days, and 16.09% occurred within 31-45 days. Among commercial abortions, 6.71% were associated with ≥1 clinically important AE, vs Medicaid (6.31%). Medication abortion-related ED visits were most common (commercial: 4.14%; Medicaid: 3.81%) followed by other abortion-related complications and hemorrhage without transfusion. The predicted incidence of AEs among commercial abortions varied by age, SES, comorbidities, and race (4.67% to 11.30%); AE-related hospitalization rates were 0.20%-0.81%. The predicted AE rate for Medicaid abortions ranged from 4.81% to 12.16%; hospitalization for major events ranged from 0.22% to 1.22%.
CONCLUSIONS: Clinically important AEs following medication abortion are rare; <1% of abortions lead to major AEs requiring hospitalization. Transparent, real-world data are critical for contextualizing clinical risk and guiding evidence-based policy decisions to ensure that abortion regulations are proportionate to measured clinical risks.

Conference/Value in Health Info

2026-05, ISPOR 2026, Philadelphia, PA, USA

Value in Health, Volume 29, Issue S6

Code

CO189

Topic

Clinical Outcomes

Topic Subcategory

Clinical Outcomes Assessment

Disease

SDC: Reproductive & Sexual Health

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