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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:

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.


Planned Parenthood

US Food and Drug Administration


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: Accessed February 16, 2017.

Emergency contraception. EBSCO DynaMed website. Available at: Updated November 7, 2016. Accessed February 16, 2017.

Emergency contraception. Family Doctor—American Academy of Family Physicians website. Available at: Updated January 2015. Accessed February 16, 2017.

Emergency contraception. The American College of Obstetricians and Gynecologists website. Available at: Updated October 2015. Accessed February 16, 2017.

Lo SS, Ho PC. Changes in contraceptive choice after emergency contraception. Int J Gynaecol Obstet. 2012;118(3):223-226.

Morning-after pill (emergency contraception). Planned Parenthood website. Available at: Accessed February 16, 2017.

Unintended pregnancy protection. Centers for Disease Control and Prevention website. Available at: Updated January 22, 2015. Accessed February 16, 2017.

Last reviewed February 2017 by Michael Woods, MD, FAAP  Last Updated: 2/16/2017