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    Emergency Contraception – Treatment

    Obstetrics and Gynecology

    Last Updated Jan 02, 2023
    Read Disclaimer
    By Kevin Shi, Mark Kang

    First 5 Minutes

    • Assess for sexual assault.
    • Assess for risk if Sex Transmitted Illness.


    • Emergency contraception (EC) is a form of acute birth control, which decreases the chance of pregnancy after unprotected intercourse, if contraceptive methods used failed, or if they were used unreliably.
    • Evaluate risks of pregnancy for every patient presenting for EC such as number of unprotected intercourse exposures, age, BMI, if they are in their fertile window in the cycle, and unreliable use of contraceptive method (e.g withdrawal or condom ripped) vs. no method.
    • Different forms of EC exist including oral medications and intrauterine devices (IUDs).
    • Most effective when used immediately but can be utilized up to 120 hours (5 days) post intercourse for oral medications, and up to 7 days with intrauterine devices.
    • Oral medications and intrauterine devices (IUDs) are not abortifacients.
      • Oral methods act to prevent ovulation if taken prior to the luteal phase of the menstrual cycle, while intrauterine methods primarily inhibit fertilization.
    • Always counsel patients on long-term contraception and barrier methods to prevent future need for EC, as patients in the year after oral EC use have pregnancy rates of 5-12 percent.
    • EC provides no protection against sexually transmitted diseases.

    Recommended Treatment

    Oral Medications

    • Progestin-only pill (Levonorgestrel 1.5mg aka “Plan B”).
      • Most effective if taken in first 12 hours, declining afterwards however remaining effective up to 72 hours post intercourse.
      • Available over-the-counter without a prescription.
      • Unintended pregnancy rate of 2.6%.
      • Common side effects include nausea and vomiting, if vomiting occurs within 2 hours of ingestion a 2nd dose is warranted as soon as possible.
      • Other side effects include abdominal pain, headache, fatigue, dizziness, breast tenderness, and temporary changes in menstrual cycle.
        • If menstrual period is delayed by 2 weeks or more after use, advise patient to take a pregnancy test.
    • Antiprogestin (Ulipristal Acetate 30mg “Ella”).
      • Effective up to 120 hours post intercourse.
      • Unintended pregnancy rate of 1.8%.
      • Counsel patients to not use progestin-containing contraceptives for 5 days afterwards, as they could interfere with the action of this method.
    • “Yuzpe Method” using combined hormonal oral contraceptives (OCPs).
      • Most effective if taken in first 12 hours, declining afterwards however remaining effective up to 120 hours post intercourse.
      • Reduces change of pregnancy from 47 – 74%.
      • Utilizes combined hormonal OCPs at the equivalent dose of 100mcg ethinyl estradiol and 0.5mg Levonorgestrel, with 2 doses 12 hours apart.
        • There is no formal medication with this dosage, however acceptable regimens are able to be found online for many common OCPs.
    • Less effective than other methods and less-tolerated by patients.
    • Low cost and wide availability make this method important for those residing in rural settings with more challenges to access other methods, or concerns with privacy.

    Intrauterine Devices (IUDs)

    • Copper 380mm2 IUD ( “Paragard”)
      • Effective up to 7 days post intercourse, and can provide up to 12 years of reversible long-term contraception.
      • Unintended pregnancy rate of 0.1%.
    • Levonorgestrel 52mg IUDs (“Mirena” and ”Liletta”)
      • Effective up to 5 days post intercourse, and can provide up to 5 years of reversible long-term contraception.
      • Unintended pregnancy rate of 0.3%, non-inferior to copper IUDs.
      • Less menstrual bleeding and cramping when compared to copper IUDs.

    Criteria For Safe Discharge Home

    All patients are safe to discharge home unless there are safety or other medical concerns in the context of the patient presentation (e.g., sexual assault).

    Quality Of Evidence?


    Many studies have been performed and validated in the literature with consistent results across all methods of current emergency contraception.


    Related Information

    Reference List

    1. Cleland K, Raymond EG, Westley E, Trussell J. Emergency contraception review: evidence-based recommendations for clinicians. Clin Obstet Gynecol. 2014 Dec;57(4):741-50. doi: 10.1097/GRF.0000000000000056. PMID: 25254919; PMCID: PMC4216625.

    2. Shen J, Che Y, Showell E, Chen K, Cheng L. Interventions for emergency contraception. Cochrane Database Syst Rev. 2017 Aug 2;8(8):CD001324. doi: 10.1002/14651858.CD001324.pub5. Update in: Cochrane Database Syst Rev. 2019 Jan 20;1:CD001324. PMID: 28766313; PMCID: PMC6483633.

    3. Turok D. Emergency Contraception. In: UpToDate. Waltham, MA. Accessed December 14, 2022. Available at: https://www.uptodate.com/contents/emergency-contraception?search=emergency%20contraception&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

    4. https://www.healthlinkbc.ca/healthlinkbc-files/emergency-contraception-ec#:~:text=What%20types%20of%20emergency%20contraception,Copper%20IUD%20(intrauterine%20device)


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