Effects of Depot Medroxyprogesterone Acetate Injection Timing on Medical Abortion Efficacy and Repeat Pregnancy: A Randomized Controlled Trial

Abstract

Objective: To evaluate the effects of timing of depot medroxyprogesterone acetate injection on medical abortion outcome and risk of repeat pregnancy within the subsequent 6 months.

Methods: In a multinational randomized trial, we assigned women undergoing medical abortion who wanted depot medroxyprogesterone acetate to administration either with mifepristone (Quickstart group) or after the abortion (Afterstart group). We ascertained abortion outcome, pregnancies, and contraception use over 7 months.

Results: From August 2013 to March 2015, we enrolled 461 participants with pregnancy durations of 75 days or less. Of participants included in the abortion outcome analyses, 14 of 220 (6.4%) and 12 of 226 (5.3%) in the Quickstart and Afterstart groups, respectively, had surgery to complete the abortion; the upper 90% confidence limit on this difference was 4.9%, within our prestipulated 5% noninferiority margin. Ongoing pregnancy after initial abortion treatment was significantly more common in the Quickstart group (8/220 [3.6%]) than in the Afterstart group (2/226 [0.9%]); the difference was 2.7% (90% confidence interval 0.4-5.6%). By 6 months, 5 of 213 (2.3%) and 7 of 217 (3.2%) in the Quickstart and Afterstart groups, respectively, became pregnant (exact log-rank test, P=.64). Use of highly effective contraceptives was significantly more common in the Quickstart group at 31 days (P<.001), but no difference was apparent at 6 months. The Quickstart group was significantly more satisfied with group assignment.

Conclusion: Depot medroxyprogesterone acetate administration with mifepristone did not appreciably increase the risk of surgery after medical abortion but did increase the risk of ongoing pregnancy. It enhanced patient satisfaction, but we found no evidence that it decreased 6-month risk of repeat pregnancy.

Clinical trial registration: ClinicalTrials.gov, https://clinicaltrials.gov, NCT01902485.