Mifepristone is NOT Recommended as Emergency Contraception
Mifepristone is not included in current U.S. guidelines for emergency contraception and should not be used for this indication. The CDC's U.S. Selected Practice Recommendations for Contraceptive Use (2013) clearly identifies only four emergency contraception options available in the United States: ulipristal acetate (30 mg), levonorgestrel (1.5 mg single dose or split dose), combined estrogen-progestin regimen, and the copper IUD 1.
Why Mifepristone Is Not Used for Emergency Contraception in the U.S.
Despite research showing mifepristone's effectiveness as emergency contraception in doses ranging from 10-600 mg when taken within 72-120 hours of unprotected intercourse 2, 3, 4, 5, 6, it has never been approved or recommended for this purpose in the United States. The FDA-approved indication for mifepristone is for medical abortion (in combination with misoprostol) and for Cushing's syndrome—not for emergency contraception 7.
Current Evidence-Based Emergency Contraception Options
For emergency contraception within 5 days of unprotected intercourse, use one of these FDA-approved options:
First-Line Options:
- Copper IUD: Most effective option; can be inserted within 5 days of unprotected intercourse (or up to 5 days after ovulation if timing can be estimated) 1
- Ulipristal acetate 30 mg: Single oral dose; more effective than levonorgestrel when taken 3-5 days after intercourse 1
Alternative Option:
- Levonorgestrel 1.5 mg: Single oral dose (or 0.75 mg twice, 12 hours apart); similar effectiveness to ulipristal acetate within first 3 days, but less effective at 3-5 days 1
Important caveat: Levonorgestrel may be less effective in obese women compared to ulipristal acetate 1.
Timing Considerations
All emergency contraceptive pills should be taken as soon as possible within 5 days of unprotected intercourse 1. While effectiveness decreases with time, particularly after 3 days, they remain options through 120 hours post-intercourse.
Why Research Findings Don't Translate to Clinical Practice
Although multiple studies demonstrated that mifepristone 10-600 mg prevents 92-100% of pregnancies when used as emergency contraception 2, 3, 4, 5, with comparable or superior efficacy to levonorgestrel 4, 6, it has not been adopted in U.S. practice. The main drawback identified in research was dose-dependent delay in subsequent menstruation (42% with mifepristone vs. 13% with standard regimens) 5, though lower doses (10 mg) reduced this effect while maintaining efficacy 3.
The absence of mifepristone from U.S. emergency contraception guidelines reflects regulatory and practical considerations rather than lack of efficacy. Its primary FDA-approved use as an abortifacient has created barriers to its use for other indications 8, and it remains subject to Risk Evaluation and Mitigation Strategy (REMS) requirements that restrict prescribing 9.
Clinical Bottom Line
Use the guideline-recommended emergency contraception options: copper IUD (most effective), ulipristal acetate 30 mg, or levonorgestrel 1.5 mg. Do not use mifepristone for emergency contraception—it is not approved, not recommended in guidelines, and not part of standard U.S. practice for this indication.