FPIN's Help Desk Answers

Misoprostol Dosing for First-Trimester Abortion


Am Fam Physician. 2020 Sep 1;102(5):online.

Clinical Question

What is the most effective way to dose misoprostol (Cytotec) for evacuating the uterus of first-trimester products of conception?

Evidence-Based Answer

Vaginal, oral, and sublingual misoprostol in single doses of 600 to 800 mcg are equally effective for promoting completed abortion in patients with an incomplete first-trimester spontaneous abortion. (Strength of Recommendation [SOR]: A, based on consistent meta-analyses of randomized controlled trials [RCTs].) When combined with mifepristone (Mifeprex), a single 800-mcg dose of vaginal or buccal misoprostol is more effective than a single 800-mcg dose of oral misoprostol for first-trimester therapeutic abortion. (SOR: A, based on a meta-analysis of RCTs.) Vaginal dosing is better tolerated than oral, buccal, or sublingual dosing. (SOR: A, based on meta-analyses of RCTs.)

Evidence Summary


Two 2017 systematic reviews evaluating misoprostol in women with incomplete first-trimester spontaneous abortion found that doses of at least 600 mcg were equally effective for uterine evacuation, regardless of the route of administration. The first review evaluated all options for the medical treatment of spontaneous abortion and included five RCTs of single-dose misoprostol regimens.1 One RCT (n = 198) comparing vaginal and oral misoprostol, 800 mcg, found similar success rates for complete uterine evacuation (relative risk [RR] = 0.94; 95% CI, 0.76 to 1.16). Two RCTs (n = 464) compared different doses of oral misoprostol: 600 mcg vs. 1,200 mcg. Both doses resulted in similar rates of complete uterine evacuation (RR = 1.00; 95% CI, 0.93 to 1.07). Two additional RCTs (n = 358) compared sublingual misoprostol, 400 to 600 mcg, with oral misoprostol, 600 mcg. Oral and sublingual administration produced similar rates of complete uterine evacuation (RR = 0.99; 95% CI, 0.94 to 1.05).

The second review 2 evaluated 18 RCTs (N = 1,802), only one of which was included in the first review.

Author disclosure: No relevant financial affiliations.

Address correspondence to Jon O. Neher, MD, at jon_neher@valleymed.org. Reprints are not available from the authors.


1. Kim C, Barnard S, Neilson JP, et al. Medical treatments for incomplete miscarriage. Cochrane Database Syst Rev. 2017;(1):CD007223.

2. Wu HL, Marwah S, Wang P, et al. Misoprostol for medical treatment of missed abortion: a systematic review and network meta-analysis. Sci Rep. 2017;7(1):1664.

3. Kulier R, Kapp N, Gülmezoglu AM, et al. Medical methods for first trimester abortion. Cochrane Database Syst Rev. 2011;(11):CD002855.

Clinical Inquiries provides answers to questions submitted by practicing family physicians to the Family Physicians Inquiries Network (FPIN). Members of the network select questions based on their relevance to family medicine. Answers are drawn from an approved set of evidence-based resources and undergo peer review. The strength of recommendations and the level of evidence for individual studies are rated using criteria developed by the Evidence-Based Medicine Working Group (https://www.cebm.net).

The complete database of evidence-based questions and answers is copyrighted by FPIN. If interested in submitting questions or writing answers for this series, go to https://www.fpin.org or email: questions@fpin.org.

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

A collection of FPIN's Clinical Inquiries published in AFP is available at https://www.aafp.org/afp/fpin.



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