Emergency Contraception
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Emergency Contraception

image Unintended pregnancy is surprisingly common. At least half of all pregnancies in the United States each year are mistimed or unplanned, because birth control measures weren't used or those that were used did not work. An emergency contraceptive pill is available to provide women with another option for preventing unintended pregnancy

It is considered one of the best-kept secrets of reproductive medicine, but emergency contraception is not new—it has been around for over 30 years. Oral contraceptives have been used for years for that purpose. There are many brands that can be used. There are also products that have been developed specifically for use only in an emergency.

Emergency contraceptive pills prevent pregnancy in a variety of ways. Depending on the time of the month in a woman's cycle, the drug may prevent ovulation (release of the egg from the ovary), interfere with fertilization, or prevent a fertilized egg from attaching in the uterus. They will not induce an abortion if a woman is already pregnant, according to the definition of pregnancy used by the National Institutes of Health and the American Congress of Obstetricians and Gynecologists.

Pregnancy Prevention—Nearly 90%

If taken within 72 hours, emergency contraceptive pills reduce the chance of pregnancy by almost 90% after one act of unprotected sex. The sooner treatment begins, the more likely it will be effective.

Some health experts have reservations about the use of emergency contraception. "I'm concerned that women will rely on this method and not take normal precautions," says Kathleen Winfield, a public health nurse in New Jersey who specializes in the prevention of infectious diseases. The convenience of swallowing two pills may indeed be attractive to those who might otherwise use a barrier method of contraception, like a condom, that helps prevent the spread of HIV and some other sexually transmitted diseases. However, studies done to evaluate this very issue have repeatedly shown that immediate access to emergency contraception does not alter a woman’s (or adolescent’s) sexual behavior nor contraception choices.

You Should Know

If you plan to take emergency contraceptive pills, here are some imporant things to keep in mind:

  • Do not swallow any extra pills. Extra pills will not further reduce your risk of pregnancy, but they could make you feel sick.
  • If you throw up within one hour of taking the pills, call your doctor. You may need to repeat a dose or take anti-nausea medicine.
  • Call your doctor if you have any of these symptoms:
    • Severe leg pain
    • Severe abdominal pain
    • Chest pain, cough, or shortness of breath
    • Blurred or loss of vision
  • Using emergency contraception frequently can cause your menstrual cycle to become irregular.
  • You should start your period within a month. If you do not have a period when you expect to, take a pregnancy test.

Other Emergency Contraceptives

Pills are not the only kind of emergency contraception available. An intrauterine device (IUD) placed in your uterus within seven days of unprotected sex can act as emergency contraception. An IUD is a type of temporary birth control for women. It is inserted into the uterus by a doctor. IUDs can be hormone-releasing or made of copper. Both are shaped like a letter “T” with a tiny string attached.

An IUD does not stop your ovaries from releasing an egg the way emergency contraceptive pills do. Instead, it can prevent an egg from becoming fertilized or from attaching to the wall of the utuerus. Emergency IUD insertion can reduce the risk of pregnancy by 99.9% if it is inserted within seven days of unprotected sex.

Where to Get Emergency Contraception

Women 17 and older can get emergency contraceptive pills at any pharmacy, without a prescription. Women under 17 must have a prescription. You can obtain a prescription through Planned Parenthood and most healthcare providers. To identify a clinic or pharmacy that carries emergency contraception, call your physician or the Emergency Contraception Hotline at 1-888-NOT-2-LATE.


The Emergency Contraception

Planned Parenthood


The Society of Obstetricians and Gynaecologists of Canada

Women's Health Matters


Answers to frequently asked questions about types of emergency contraception. The Emergency Contraception Website. Available at: http://ec.princeton.edu/questions/dose.html#dose. Updated April 2011. Accessed June 21, 2011.

Emergency contraception. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/. Updated May 2011. Accessed June 21, 2011.

Emergency contraception. American Academy of Family Physicians. FamilyDoctor.org website. Available at: http://familydoctor.org/online/famdocen/home/women/contraceptive/805.html. Updated January 2011. Accessed June 21, 2011.

Intrauterine device insertion. EBSCO Health Library website.Available at: http://www.ebscohost.com/healthLibrary/. Updated January 2011. Accessed June 21, 2011.

Piaggio G, von Hertzen H, Grimes DA, Van Look PFA. For: Task Force on Postovulatory Methods of Fertility Regulation. Timing of emergency contraception with levonorgestrel or the Yuzpe regimen. Lancet. 1999;353:721.

Preven website. Available at: http://www.preven.com .

Task Force on Postovulatory Methods of Fertility Regulation. Randomised controlled trial of levonorgestrel versus the Yuzpe regimen of combined oral contraceptives for emergency contraception. Lancet. 1998;352:428-433.

Unintended pregnancy. Department of Health and Human Services: Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/reproductivehealth/unintendedpregnancy/index.htm. Updated April 2010. Accessed June 20, 2011.

8/23/2010 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : US Food and Drug Administration. FDA approves ella tablets for prescription emergency contraception. US Food and Drug Administration website. Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm222428.htm . Updated August 13, 2010. Accessed August 23, 2010.

Last reviewed June 2011 by Brian Randall, MD

Last updated Updated: 6/21/2011

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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