Not Found
Locations

Find information on medical topics, symptoms, drugs, procedures, news and more, written for the health care professional.

Emergency Contraception (EC)

By Laura Sech, MD, Family Planning Fellow, Department of Obstetrics and Gynecology, University of Southern California Keck School of Medicine ; Penina Segall-Gutierrez, MD, MSc, Adjunct Associate Professor of Family Medicine and Obstetrics and Gynecology, Keck School of Medicine, University of Southern California ; Emily Silverstein, MD, Research Project Manager, Department of Obstetrics and Gynecology, University of Southern California Keck School of Medicine ; Daniel R. Mishell, Jr., MD, MSc, Endowed Professor of Obstetrics and Gynecology, Keck School of Medicine, University of Southern California

Click here for
Patient Education

Commonly used emergency contraception (EC) regimens include

  • Insertion of a copper-bearing T380A IUD within 5 days of unprotected intercourse

  • Levonorgestrel 0.75 mg po in 2 doses 12 h apart within 120 h of unprotected intercourse

  • Levonorgestrel 1.5 mg po once within 120 h of unprotected intercourse

  • Ulipristal acetate 30 mg po once within 120 h of unprotected intercourse

For women who have regular menses, the risk of pregnancy after a single act of intercourse is about 5%. This risk is 20 to 30% if intercourse occurs at midcycle.

When a copper-bearing IUD is used for EC, it must be inserted within 5 days of unprotected intercourse or within 7 days of suspected ovulation. The pregnancy rate with this EC method is 0.1%. Also, the IUD can be left in place to be used for long-term contraception. As EC, the copper-bearing IUD may affect blastocyst implantation; however, it does not appear to disrupt an already established pregnancy.

EC with levonorgestrel prevents pregnancy by inhibiting or delaying ovulation. The probability of pregnancy is reduced by 85% after levonorgestrel EC, which has a pregnancy rate of 2 to 3%. However, overall risk reduction depends on the following:

  • The woman's risk of pregnancy without EC

  • The time in the menstrual cycle that EC is given

  • The woman's BMI (levonorgestrel EC is less effective than ulipristal acetate in obese women with a body mass index [BMI] > 30)

Ulipristal acetate (a progestin-receptor modulator) has a pregnancy rate of about 1.5% and is thus more effective than levonorgestrel. Ulipristal acetate, like levonorgestrel, prevents pregnancy primarily by delaying or inhibiting ovulation. Although ulipristal acetate is more effective than levonorgestrel for women with a BMI > 30, its effectiveness also decreases as BMI increases. Thus, in obese women who strongly desire to avoid an unintended pregnancy, the copper-bearing IUD is the preferred method for EC.

There are no absolute contraindications to levonorgestrel or ulipristal acetate EC. Levonorgestrel EC is available behind pharmacy counters without a prescription. Ulipristal acetate is available by prescription only. Levonorgestrel and ulipristal EC should be taken as soon as possible and within 120 h of unprotected intercourse.

Another regimen (the Yuzpe method) consists of 2 tablets, each containing ethinyl estradiol 50 mcg and levonorgestrel 0.25 mg, followed by 2 more tablets taken 12 h later but within 72 h of unprotected intercourse. The high estrogen dose often causes nausea and may cause vomiting. This method is also less effective than other methods; thus, it is no longer recommended except when women do not have access to other methods.

EC can be given when another hormonal contraceptive is started as part of a quick-start protocol. A urine pregnancy test 2 wk after use of EC is recommended.

Key Points

  • Usually, hormones (eg, ulipristal acetate, levonorgestrel) are used for emergency contraception (EC); they are taken as soon as possible within 120 h of unprotected intercourse.

  • A copper-bearing IUD, inserted within 5 days of unprotected intercourse, is also effective and can be left in place for long-term contraception.

  • Pregnancy rates are 1.5% with ulipristal acetate, 2 to 3% with levonorgestrel, and 0.1% with a copper-bearing IUD.

  • Likelihood of pregnancy after hormonal EC depends on pregnancy risk without EC, time in the menstrual cycle that EC is taken, and the woman's BMI.

Drugs Mentioned In This Article

  • Drug Name
    Select Trade
  • MIRENA, PLAN B
  • ESTRADERM, ESTROGEL, VIVELLE
  • ELLA