Medication Abortion Safety and Effectiveness With Misoprostol Alone.

Importance: Misoprostol-alone regimens for abortion may be more effective than previously thought. Objective: To estimate the effectiveness of medication abortion with misoprostol alone among individuals self-managing their abortion. Design, Setting, and Participants: For this prospective observational cohort study of callers to safe abortion hotlines and accompaniment groups in Argentina, Nigeria, and Southeast Asia, participants were recruited between July 31, 2019, and October 1, 2020, prior to starting their medication abortion. Eligible participants were 13 years or older, had no contraindications to medication abortion, and were not currently bleeding. Participants completed a baseline and 2 follow-up surveys. The analysis was restricted to participants who reported using misoprostol alone and was performed between January 6, 2022 and September 8, 2023. Exposure: Self-managed medication abortion using misoprostol alone. Main Outcomes and Measures: The primary outcome was effectiveness, defined as participant self-report of complete abortion without procedural intervention, measured at 1 week and 3 weeks after taking misoprostol. Secondary outcomes included method safety, measured by self-report of experiencing warning signs (eg, heavy bleeding, pain, fever, discharge) indicative of a potential complication and by medical treatment (eg, blood transfusion, intravenous fluids, overnight hospital stay) indicative of a potential adverse event. Additional outcomes included length of bleeding and cramping, time to expulsion, and experience of adverse effects. Results: Among 1352 enrolled participants, 637 used misoprostol-alone regimens for abortion and were included in the analysis (591 [92.8%] from Nigeria, 45 [7.1%] from Southeast Asia, and 1 [0.2%] from Argentina; 384 [60.2%] aged 20-29 years; 317 [49.8%] with pregnancy durations <7 weeks and 205 [32.2%] with pregnancy durations between 7 and <9 weeks). At last follow-up after taking medication (median, 22 days; IQR, 21-26 days), 625 participants (98.1%; 95% CI, 96.7%-98.9%) had a complete abortion without procedural intervention. Potential adverse events were reported by 6 participants (0.9%; 95% CI, 0.4%-2.1%). Most participants experienced bleeding for less than 1 week (median, 4 days; IQR, 3-6 days) and expelled their pregnancy within 24 hours of starting the abortion process (median, 12 hours; IQR, 9-15 hours). Common side effects included nausea (335 participants [52.6%]), fever (232 [36.4%]), and diarrhea (181 [28.4%]). Conclusions and Relevance: The findings suggest that misoprostol alone is a highly effective method of pregnancy termination. Future research should explore strategies to maximize the effectiveness of misoprostol alone in clinical and nonclinical settings.