A Non-Inferiority Study of Outpatient Mifepristone-Misoprostol Medical Abortion at 64-70 Days and 71-77 Days of Gestation

Medical abortion with mifepristone and misoprostol is increasingly used as an outpatient alternative to aspiration, but it is not offered beyond 10 weeks of pregnancy in many clinics and facilities as a first trimester option due to limited evidence. We sought to bridge the evidence gap about outpatient medical abortion in the later first trimester. Better information about how well a common medical abortion regimen works in the 11^th week of pregnancy would be beneficial for health providers and for people who prefer to avoid aspiration procedures. If effective, it could increase access to safe abortion care where providers trained in aspiration are scarce.

We conducted a multi-center study to evaluate the success of mifepristone 200mg followed 24-48 hours later by misoprostol 800mcg buccally (in the cheeks) among people with 10 and 11 week pregnancies who were seeking abortion. In addition to method success, we assessed whether study participants were prepared to manage the procedure at home. Our findings show a very good chance of success, regardless of pregnancy age. Successful abortion occurred in 92.3% of the 10^th week pregnancies (which is consistent with other published studies) and in 86.7% of the 11^th week pregnancies. The reason for the lower success rate in the 11^th week was because nearly 9% of pregnancies continued after using the medication regimen. Pain, bleeding and acceptability measures did not differ by pregnancy age, and participants were able to manage their expulsions at home without making calls to the clinic. This regimen could be a reasonable option for medical abortion users with 11 week pregnancies, given high success and acceptability, but the significant increase in continuing pregnancies is concerning. Forthcoming evidence will shed light on the potential role of an additional dose of misoprostol at 10 and 11 weeks of pregnancy.

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