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Emergency Contraception


The Manual's Editorial Staff

Last full review/revision Jun 2021| Content last modified Jun 2021
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What is emergency contraception?

Emergency contraception is birth control (something used to prevent pregnancy) that you use after you've had sex. You can use it if you have sex without birth control or if your birth control fails, such as when a condom breaks.

There are 2 main types of emergency contraception:

  • Medicines ("morning-after pills")

  • Getting a copper IUD (intrauterine device) inserted in your uterus

These methods are called "emergency" because you should be using another method to keep from getting pregnant. You shouldn't depend on doing something after you have sex.

  • Use emergency birth control as soon as you can after sex to avoid getting pregnant—the sooner you use it, the greater the chance it will work

  • You can get several different types of medicine that work as emergency contraception pills

  • Putting in a copper IUD is the most effective form of emergency birth control and will continue to prevent pregnancy for up to 10 years (or until you have it removed)

What are the types of emergency birth control?

Pills are more commonly used as emergency birth control, but a copper IUD works better and provides ongoing birth control.

Medicines for emergency contraception (morning-after pills)

These are pills you take soon after sex to avoid getting pregnant.

There are several different kinds of morning-after pills:

  • Levonorgestrel must be taken within 3 days of sex—in the United States it's available over the counter (without a prescription) at pharmacies

  • Ulipristal acetate must be taken within 5 days of sex—you need a doctor's prescription to get it

  • Combination oral contraceptives (birth control pills), available with a doctor's prescription, can also be used but sometimes cause nausea and vomiting—you take 2 pills followed by another 2 pills 12 hours later

Levonorgestrel works better the sooner after sex you take it. It doesn't work as well in obese women.

Copper IUDs

A copper IUD is a small T-shaped plastic device wrapped in copper wire that is placed in your uterus (womb) to prevent pregnancy.

  • Your doctor must put in the copper IUD

  • You must have it put in within 5 days of having sex

  • The IUD can be left in as birth control for up to 10 years

How well does emergency birth control work?

When used correctly, emergency birth control works for most women who use it.

  • Using levonorgestrel, about 20 to 30 in 1000 women get pregnant

  • Using ulipristal acetate, about 15 in 1000 women get pregnant

  • Combination birth control pills don’t work as well as levonorgestrel or ulipristal

  • Using the copper IUD, about 2 in 1000 women get pregnant

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