Second Trimester Medication Abortion Regimens and the Mifepristone-Misoprostol Dosing Interval
The purpose of this article is to review current methods of induction termination of pregnancy in the second trimester. The specific area of focus is recent publication regarding timing of mifepristone and misoprostol dosing. In the context of Reproductive Medicine, current international guidelines recommend initial treatment with mifepristone followed by misoprostol after 24 to 48 h.
Clinical Findings and Efficacy
Recent findings from retrospective studies indicate that a shorter interval between mifepristone and misoprostol of less than 12 h or even concomitant administration may result in a shorter total abortion time without increasing risk of incomplete abortion or complications. Given the potential benefit of increased efficacy, with successful expulsion of the pregnancy, and reduced time to delivery with shorter mifepristone-misoprostol intervals or concurrent administration practitioners should offer all second trimester medication abortion treatment with mifepristone.
Data Summary of Dosing Regimens
- Standard Interval: Mifepristone followed by misoprostol after 24 to 48 hours.
- Shortened Interval: Interval of less than 12 hours between medications.
- Concurrent Administration: Concomitant dosing of mifepristone and misoprostol.
- Primary Outcomes: Shorter total abortion time and reduced time to delivery.
Key Subjects in Pharmacotherapy
Research in this field covers several subjects of particular interest, published recently, including:
- Dosage compensation
- Obstetrics
- Pharmacotherapy
- Phase II trials
- Pregnancy Outcome
Future Directions in Medical Abortion
Further studies are needed to evaluate the implementation of concurrent or varied dosing intervals and the magnitude of benefit vs risks, with attention to the patient experience, resources, and costs. Relevant research includes an observational study on Second-Trimester Medical Abortion with Misoprostol Preceded by Two Sequential Doses of Mifepristone and the dosing interval between mifepristone and misoprostol in second and third trimester termination.