Ulipristal plus misoprostol shows promise for medication abortion

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Ulipristal acetate followed by misoprostol is effective and acceptable for use as medication abortion, according to a recent study published in the New England Journal of Medicine.¹

While a combination of mifepristone and misoprostol is recognized as the clinical standard for medication abortion, access remains limited in many countries. Ulipristal is a similar drug to mifepristone, binding to the progesterone receptor with high affinity, a wide margin of safety, and good oral availability.

According to investigators, ulipristal acetate “has shown to be a feasible and acceptable regimen for cervical preparation in second-trimester abortions prior to dilation and evacuation.” A case series was conducted to expand on this data by assessing ulipristal followed by misoprostol for induced abortion within the first 63 days of pregnancy.

A 60 mg and a 90 mg oral ulipristal dose were both evaluated, followed by 800 μg of buccal misoprostol after 24 hours. A structured exit survey was completed by participants to assess acceptability outcomes.

Satisfaction ratings ranged from “very satisfied” to “very unsatisfied,” and pain acceptability from “very acceptable” to “very unacceptable.” Pain was also measured on a numerical scale from 0 to 10, with higher scores indicating increased pain.

Participants included adult women residing in Mexico City and eligible for medication abortion use in an intrauterine pregnancy under 64 days’ gestation. Additional eligibility criteria included a body mass index of 32 or less, access to a telephone for follow-up communication, and responding to a short list of questions.

Patients with ectopic pregnancy, a history of hepatic or renal disease, undiagnosed adnexal mass, gestational trophoblastic disease, administered intrauterine device, and certain allergies were excluded from the analysis. Participants received ulipristal at the clinic and were observed for 1 hour to assess adverse events.

After the 1-hour period, patients were discharged with 4 200-μg misoprostol pills to take at home. Follow-up evaluations were performed after 7 to 10 days, with efficacy determined by complete termination of the intrauterine pregnancy.

Participant report allowed additional adverse events to be captured. The efficacy and safety of the regimen was reported as the primary outcome of the analysis.

There were 133 participants included in the final analysis, undergoing a follow-up visit at a median 14 days. Of participants, 97% reported pregnancy at the follow-up visit, while the remaining 4 underwent additional interventions.

Adverse events were reported by 3 participants. One patient reported nearly fainting after taking misoprostol, another reported mild maculopapular rash after taking misoprostol, and the final presented with urinary tract infection. All 3 adverse events received treatment, and no severe adverse events were reported.

Under 4% of participants reported side effects after taking ulipristal. After taking misoprostol, the most common side effect was chills in 77.4% of patients. This was followed by diarrhea in 66.9%, nausea in 48.1%, fever in 38.1%, and vomiting in 27.1%.

Of participants, 97.7% reported the treatment as satisfactory or very satisfactory. Additionally, 85% reported the pain level as being acceptable or very acceptable. Only 6% reported the pain as unacceptable or very unacceptable, while the remainder reported neutral pain acceptability.

These results indicated efficacy and acceptability of a combined ulipristal and misoprostol regimen for medication abortion. Investigators concluded “the findings prompt further consideration of ulipristal in the evolving landscape of medication abortion.”

“As a form of emergency contraception, ulipristal acetate works by delaying ovulation, thus preventing pregnancy,” said Stella Dantas, MD, FACOG, president of the American College of Obstetricians and Gynecologists.² “This new study demonstrates that in a different, higher dosage, ulipristal acetate may have a different mode of action that, in combination with misoprostol, ends a pregnancy.”

References

1. Winikoff B, Bousiéguez M, Salmerón J, et al. A proof-of-concept study of ulipristal acetate for early medication abortion. NEJM Evid. 2025;4(2). doi:10.1056/EVIDoa2400209
2. ACOG responds to new study on ulipristal acetate. American College of Obstetricians and Gynecologists. January 23, 2025. Accessed February 5, 2025. https://www.acog.org/news/news-releases/2025/01/acog-responds-to-new-study-on-ulipristal-acetate