Similar success, different expulsion rates with 12-, 24-hour medication abortion regimens

Key takeaways:

• Median time to fetal expulsion was shorter after mifepristone but longer after misoprostol with the 12- vs. 24-hour regimen.
• Success rates, adverse effects and satisfaction levels were similar for both regimens.

SAN FRANCISCO — For second-trimester medical abortion, 12- and 24-hour mifepristone-misoprostol regimens produced similar success rates, adverse effects and satisfaction but different times to mifepristone and misoprostol fetal expulsion.

“Misoprostol is currently recommended as the go-to agent for second trimester abortion. It's cheap, it's easy to use and it's efficient,” Raanan Meyer, MD, physician at Cedars-Sinai Medical Center, Los Angeles, said during a presentation at the ACOG Annual Clinical & Scientific Meeting. “In addition, mifepristone prior to misoprostol is considered the most efficient method for second trimester abortion.”

Meyer and colleagues conducted a prospective randomized controlled trial from July 2020 to June 2023 to compare 12- and 24-hour mifepristone-misoprostol regimens for second-trimester medical abortion. Eighty women in Israel were randomly assigned to mifepristone 12 (n = 40) or 24 (n = 40) hours before misoprostol administration.

Primary outcomes were time from mifepristone and misoprostol administration to fetal expulsion.

Median time from mifepristone administration to fetal expulsion was 8.5 hours shorter with the 12-hour regimen compared with the 24-hour regimen (24.5 vs. 33 hours; P = .001). Median time from first misoprostol administration to fetal expulsion was 3 hours longer with the 12- vs. 24-hour regimen (12.5 vs. 9.5 hours; P = .028).

At 12 hours after misoprostol administration, abortion was complete for 45% of women in the 12-hour regimen group and 62.5% of women in the 24-hour regimen group. At 24 hours after misoprostol administration, abortion was complete for 75% of women in the 12-hour regimen group and 90% of women in the 24-hour regimen group.

Researchers observed comparable needs for additional medical and/or surgical treatment for uterine evacuation between the 12- and 24-hour groups. In addition, pain scores, adverse effects and satisfaction levels were similar for women in both groups.

“We believe that these findings are important for patients and can provide more patient-centered care, more flexibility, potentially shorter hospitalization time and also provide providers with more flexibility,” Meyer said.