New Study to Further the Evidence-Base for a Later First Trimester Medication Abortion Regimen

Gynuity Health Projects has initiated a study to strengthen the evidence for extending the gestational age limit for outpatient medication abortion beyond 70 days of pregnancy—the current limit set by the U.S. Food and Drug Administration. This latest in a trilogy of studies will explore with more rigor an adjustment to the dosing regimen in the later first trimester (11 and 12 weeks of pregnancy).

With a grant from the Society of Family Planning Research Fund, we have partnered with four clinics in the U.S. to evaluate the efficacy at 71-77- and 78-84-days’ gestation of an outpatient combination regimen that uses one 200mg dose of mifepristone followed in 24 to 48 hours by two 800mcg doses of misoprostol, taken buccally four hours apart. The study will at the same time evaluate side effects as well as client experience with the protocol.

Having a reliable regimen for medication abortion through 11 and 12 weeks of pregnancy would broaden options, making it easier for people to obtain care both in and out of health facilities. It would help those who, for instance, live far from providers trained to perform uterine aspiration, prefer to avoid aspiration abortion, or experience delays in getting clinic appointments due to surging demand in states where the procedure is still available. Better information about the efficacy of a mifepristone-misoprostol regimen in the later first trimester could also provide greater reassurance for people around the world who choose self-managed abortion.

Our four clinic partners in this study are Planned Parenthood Great Northwest, Hawai'i, Alaska, Indiana, Kentucky (PPGNHAIK); Philadelphia Women’s Center; Planned Parenthood North Central States (PPNCS); and the Queen's Medical Center (Hawaii). An additional two clinics—one in Tennessee and the other in Georgia—had to withdraw from the study due to the enforcement of post-Roe abortion bans in their states.

This new study builds on our two published studies evaluating the success of combined mifepristone-misoprostol regimens for abortion through the 11th week of pregnancy.

The first study prospectively assessed the efficacy of a common first trimester outpatient regimen using one dose of mifepristone 200mg and one dose of misoprostol 800mcg. Our findings demonstrated a particularly good chance of abortion success: 92.3% and 86.7% in the 10th and 11th week, respectively. Ongoing pregnancy was 3.6% and 8.7%, respectively. This regimen could be a reasonable option for medication abortion at 11 weeks, but the findings indicated that the significant increase in continuing pregnancies in the later week was cause for concern.

The second study, a retrospective chart review, compared the regimen effectiveness of outpatient medication abortion at 10- and 11-weeks’ gestation using a second 800mcg dose of misoprostol, four hours after the first one, following a 200mg dose of mifepristone taken up to 48 hours earlier. Findings showed that treatment success was seemingly higher (99.6% and 97.7% in the 10th and 11th weeks, respectively) and ongoing pregnancy was much lower (0.4% and 1.4%, respectively) than what we had observed in the first study. A quarter of clients did not return to the clinic for follow up, making it difficult to draw definitive conclusions about the efficacy of the study regimen. The regimen, however, showed promise and warranted more rigorous investigation.