Emergency Contraception

image Unintended pregnancy is surprisingly common. Nearly half of all pregnancies in the US each year are mistimed or unplanned, because birth control measures were not 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

There are many options for birth control, but 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 120 hours (5 days), 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. They argue that women may not take normal precautions. The convenience of swallowing 2 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 topic 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 important 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 1 hour of taking the pills, call your doctor. You may need to repeat a dose or take anti-nausea medication.
  • Call your doctor if you have any of these symptoms:
    • Severe leg pain
    • Severe abdominal pain
    • Persistent headache
    • Persistent nausea or vomiting
    • 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 5 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 uterus. Emergency IUD insertion can reduce the risk of pregnancy by 99.9% if it is inserted within 5 days of unprotected sex.

Where to Get Emergency Contraception

Women 15 and older can get emergency contraceptive pills at any pharmacy, without a prescription. Adolescents under 15 must have a prescription. You can obtain a prescription through Planned Parenthood and most healthcare providers. To identify a vendor that carries emergency contraception, call your doctor, local pharmacy, or public health department.


US Food and Drug Administration


The Society of Obstetricians and Gynaecologists of Canada
Women's Health Matters


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Morning-after pill (emergency contraception). Planned Parenthood website. Available at: https://www.plannedparenthood.org/learn/morning-after-pill-emergency-contraception. Accessed February 16, 2017.
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Last reviewed February 2017 by Michael Woods, MD, FAAP
Last Updated: 2/16/2017

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