---
title: "Mifepristone vs Other Emergency Contraception: Effectiveness, Safety, and Acceptability"
id: "pubmed-42764179"
canonical_url: "https://medichelpline.com/clinical-feed/pubmed-42764179"
content_type: "clinical_feed_article"
specialty: "Pharmacology"
source_name: "PubMed / NCBI"
source_url: "https://pubmed.ncbi.nlm.nih.gov/42764179/"
doi: "10.1002/14651858.CD016275"
published_at: "2026-09-21T00:00:00.000Z"
evidence_level: "Journal Article"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Mifepristone vs Other Emergency Contraception: Effectiveness, Safety, and Acceptability
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/pubmed-42764179
- **Specialty:** [Pharmacology](https://medichelpline.com/clinical-feed/pharmacology.md)
- **Primary Source:** PubMed / NCBI
- **Source URL:** [Original Journal Publication](https://pubmed.ncbi.nlm.nih.gov/42764179/)
- **DOI:** [10.1002/14651858.CD016275](https://doi.org/10.1002%2F14651858.CD016275)
- **Published At:** 2026-09-21T00:00:00.000Z
- **Evidence Rating:** Journal Article
## Executive GIST (TL;DR)
- This Cochrane systematic review evaluated **mifepristone** versus other emergency contraception options (oral pills and IUDs) to prevent pregnancy in reproductive-age women presenting within five days of unprotected intercourse. - The review included 87 randomized trials (~36,000 participants) searched through 28 February 2025; most studies (79) were conducted in China. - Comparisons included mifepristone versus **levonorgestrel**, the **Yuzpe regimen**, dose-comparisons of mifepristone, and two trials versus **copper IUD**. Non-randomized studies were identified but excluded because they added no unique outcome data. - Low-dose mifepristone (<25 mg) reduced pregnancies versus levonorgestrel with high-certainty evidence (RR 0.73). Mid-dose (25–50 mg) also likely reduced pregnancies (RR 0.67; moderate certainty). - Mifepristone (any dose) probably reduced pregnancies versus the **Yuzpe regimen** (RR 0.14; moderate certainty) and was associated with fewer nausea/vomiting events but increased **delayed menses** risk. - Dose comparisons: mid-dose versus low-dose mifepristone slightly reduced pregnancies but increased delayed menses; certainty ranged up to high for these outcomes. - Evidence comparing mifepristone to **copper IUD** was very low certainty and insufficient to draw reliable conclusions for pregnancy prevention or side effects. - Adverse-event findings: overall fewer reported side effects with mifepristone than levonorgestrel or Yuzpe; delayed menses was the main adverse effect and greater with higher mifepristone doses. - Many studies had unclear risk of bias due to reporting gaps (randomization, allocation concealment, blinding, incomplete data) and generalizability may be limited given the geographic concentration of trials. - Authors conclude both low- and mid-dose mifepristone are probably more effective than levonorgestrel and likely more effective than the Yuzpe regimen; nausea/vomiting are less common with mifepristone, and delayed menses is the principal adverse effect.
## Clinical Analysis & Structured Key Points
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Affiliations Expand ### Affiliations * 1 Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA. * 2 Centre for Clinical Research and Training, Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, China. * 3 Kaiser Permanente Center for Health Research Evidence-based Practice Center, Kaiser Permanente, Portland, OR, USA. * PMID: **42764179** * DOI: [ 10.1002/14651858.CD016275 ](https://doi.org/10.1002/14651858.cd016275) Item in Clipboard Review # Mifepristone versus other interventions for the prevention of pregnancy in reproductive-age women using emergency contraception Shaalini Ramanadhan et al. Cochrane Database Syst Rev. 2026. Show details Display options Display options Format Abstract PubMed PMID Cochrane Database Syst Rev Actions * [ Search in PubMed ](https://pubmed.ncbi.nlm.nih.gov/?term=%22Cochrane+Database+Syst+Rev%22%5Bjour%5D&sort=date&sort_order=desc) * [ Search in NLM Catalog ](https://www.ncbi.nlm.nih.gov/nlmcatalog?term=%22Cochrane+Database+Syst+Rev%22%5BTitle+Abbreviation%5D) * [ Add to Search ](https://pubmed.ncbi.nlm.nih.gov/42764179/) . 2026 Sep 21:9:CD016275. doi: 10.1002/14651858.CD016275. ### Authors [Shaalini Ramanadhan](https://pubmed.ncbi.nlm.nih.gov/?term=Ramanadhan+S&cauthor_id=42764179)[ 1 ](https://pubmed.ncbi.nlm.nih.gov/42764179/#short-view-affiliation-1 "Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA."), [Alison Edelman](https://pubmed.ncbi.nlm.nih.gov/?term=Edelman+A&cauthor_id=42764179)[ 1 ](https://pubmed.ncbi.nlm.nih.gov/42764179/#short-view-affiliation-1 "Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA."), [Yan Che](https://pubmed.ncbi.nlm.nih.gov/?term=Che+Y&cauthor_id=42764179)[ 2 ](https://pubmed.ncbi.nlm.nih.gov/42764179/#short-view-affiliation-2 "Centre for Clinical Research and Training, Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, China."), [Robin A Paynter](https://pubmed.ncbi.nlm.nih.gov/?term=Paynter+RA&cauthor_id=42764179)[ 1 ](https://pubmed.ncbi.nlm.nih.gov/42764179/#short-view-affiliation-1 "Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA."), [Alyssa Hersh](https://pubmed.ncbi.nlm.nih.gov/?term=Hersh+A&cauthor_id=42764179)[ 1 ](https://pubmed.ncbi.nlm.nih.gov/42764179/#short-view-affiliation-1 "Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA."), [Jillian T Henderson](https://pubmed.ncbi.nlm.nih.gov/?term=Henderson+JT&cauthor_id=42764179)[ 3 ](https://pubmed.ncbi.nlm.nih.gov/42764179/#short-view-affiliation-3 "Kaiser Permanente Center for Health Research Evidence-based Practice Center, Kaiser Permanente, Portland, OR, USA.") ### Affiliations * 1 Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA. * 2 Centre for Clinical Research and Training, Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, China. * 3 Kaiser Permanente Center for Health Research Evidence-based Practice Center, Kaiser Permanente, Portland, OR, USA. * PMID: **42764179** * DOI: [ 10.1002/14651858.CD016275 ](https://doi.org/10.1002/14651858.cd016275) Item in Clipboard Cite Display options Display options Format Abstract PubMed PMID ## Abstract **Rationale:** Emergency contraception uses drugs or intrauterine devices to prevent pregnancy after unprotected intercourse. Understanding the effectiveness, safety, and acceptability of the various methods available is critical for reproductive healthcare providers and their patients. **Objectives:** To evaluate the effectiveness, safety, and acceptability of mifepristone compared to other interventions in reproductive-age women using emergency contraception for the prevention of pregnancy. **Search methods:** We used CENTRAL, MEDLINE, Embase, two other databases, and two trial registers, together with reference checking and contact with study authors and experts in the field, to identify the studies included in the review. The latest search date was 28 February 2025. **Eligibility criteria:** We included randomized controlled trials (RCTs) comparing mifepristone to oral emergency contraception pills (levonorgestrel, the Yuzpe regimen, and ulipristal acetate) or copper or levonorgestrel intrauterine devices (IUDs). We also planned to include non-randomized studies of interventions (NRSIs) for capturing rare adverse outcomes and detecting minimal clinically important differences (MCIDs). Participants were women seeking emergency contraception within five days of unprotected intercourse. **Outcomes:** The critical outcome was the number of pregnancies. Important outcomes included any side effects, altered menses, and acceptability, assessed as treatment satisfaction. **Risk of bias:** We used Cochrane's RoB 1 tool to assess the risk of bias in the RCTs. **Synthesis methods:** We synthesized results for each outcome using meta-analysis where possible, using both fixed-effect and random-effects models. We used GRADE to assess the certainty of evidence for each outcome. **Included studies:** We included 87 studies with approximately 36,000 participants. Seventy-nine studies were conducted in China, four in the UK, two in Cuba, and two were multi-country studies. Forty-one studies compared mifepristone with levonorgestrel; three with the Yuzpe regimen (estrogen and progestin); 42 compared two or more doses of mifepristone; and two compared mifepristone with copper IUD. We excluded all relevant NRSIs identified because none reported additional outcome data that were unavailable from the included RCTs. **Synthesis of results:** Mid-dose mifepristone (25 mg to 50 mg) versus levonorgestrel Compared to levonorgestrel, mid-dose mifepristone likely results in fewer pregnancies (risk ratio (RR) 0.67, 95% confidence interval (CI) 0.49 to 0.91; I2 = 0%; 27 studies, 6052 participants) and likely reduces the occurrence of any side effects (RR 0.55, 95% CI 0.39 to 0.76; I2 = 72%; 17 studies, 4350 participants), both with moderate-certainty evidence. It probably leads to fewer occurrences of early menses (RR 0.71, 95% CI 0.49 to 1.03; 7 studies, 1324 participants), but a higher risk of delayed menses (RR 1.29, 95% CI 1.01 to 1.64; I2 = 25%; 17 studies, 3615 participants), both with moderate-certainty evidence. No studies reported on acceptability. Low-dose mifepristone ( (accessed 30 September 2025). 2. 1. World Health Organization. Trends in maternal mortality 2000 to 2020: estimates by WHO, UNICEF, UNFPA, World Bank Group and UNDESA/Population Division; February 2023. Available at: (accessed 30 September 2025). 3. 1. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 152. Emergency contraception. Obstetrics & Gynecology 2015;3:e1-e11. [DOI: 10.1097/AOG.0000000000001047] [PMID: 26287787] - [PubMed](https://pubmed.ncbi.nlm.nih.gov/26287787/) 4. 1. World Health Organization. Emergency contraception fact sheet; November 2021. Available at (accessed 30 September 2025). 5. 1. Puig C. Russian Federation: Mifepristone EC pills less accessible; March 2025. European Consortium for Emergency Contraception. Available from: [https://www.ec-ec.org/russian-federation-mifepristone-ec-pills-less-acce...](https://www.ec-ec.org/russian-federation-mifepristone-ec-pills-less-accessible/) (accessed prior to 30 August 2026). Show all 107 references ## Publication types * Systematic Review Actions * [ Search in PubMed ](https://pubmed.ncbi.nlm.nih.gov/?term=%22Systematic+Review%22%5Bpt%5D&sort=date&sort_order=desc) * [ Search in MeSH ](https://www.ncbi.nlm.nih.gov/mesh?term=Systematic+Review) * [ Add to Search ](https://pubmed.ncbi.nlm.nih.gov/42764179/) * Meta-Analysis Actions * [ Search in PubMed ](https://pubmed.ncbi.nlm.nih.gov/?term=%22Meta-Analysis%22%5Bpt%5D&sort=date&sort_order=desc) * [ Search in MeSH ](http
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