"False positive" urine pregnancy test results after successful medication abortion.

ABSTRACT Objective: To examine the proportion of high-sensitivity urine pregnancy test (HSPT) results that were positive by time after successful medication abortion. Study Design: We used data from an ongoing study that provides mifepristone and misoprostol for medication abortion by direct-to-patient telemedicine and mail. Providers evaluated abortion outcomes by patient interview and clinical tests per clinical judgment and participant preference. We identified all participants enrolled July 2016 – September, 2020 who had an HSPT result and no indication of viable pregnancy after treatment. We used logistic regression to examine the association between the timing of the initial post-treatment HSPT, gestational age, and the proportion of HSPTs that gave a positive result. Results: Of the 472 participants in our analysis, 88 (18%) had positive initial HSPTs. The proportions that were positive at ≤20 days, 21-27 days, 28-34 days and ≥35 days after mifepristone ingestion was 14/29 (48%), 15/58 (26%), 49/258 (19%), and 10/127 (8%) respectively (p Conclusions: The proportion of participants with positive HSPTs declined with time after successful medication abortion. However, nearly one-fifth of participants with complete abortion had positive tests 4 weeks after treatment.