ED Contraception Emergency Plan B

Emergency Contraception (EC)

Emergency contraception (EC) is used to prevent a pregnancy after a woman has had unprotected sex. EC prevents pregnancy in different ways. It may (1) prevent the egg from leaving the ovary; (2) stop the sperm from reaching the egg; or (3) keep the fertilized egg from attaching to the womb (uterus). EC is sometimes called the "morning after pill." However, this name is misleading because some types of EC can work up to 5 days after having sex, not just the morning after. EC is not an abortion pill. It does not work if you are already pregnant. If you are overweight or obese, certain types of EC may not work as well for you. Talk with your healthcare provider about your options.

When to use EC

You may want to use EC in any of the following types of situations:

  • You had sex without birth control (unprotected sex).
  • You were forced to have sex.
  • You were using a condom but it broke or came off.
  • You forgot to take your pill or missed your shot.
  • You suspect that your ring, patch, diaphragm, cervical cap, sponge, or spermicide was not used correctly.
  • You use the natural family planning method and had unprotected sex at a time when you are likely to become pregnant. (This is usually week 2 or 3 of a 4-week cycle, if your periods are regular.)
  • You were using the withdrawal method, and he didn't pull out in time.
  • Your IUD came out.
  • You think your regular birth control method failed.

Note: EC does not protect you from sexually transmitted diseases (STDs). To protect against STDs when having sex, a condom must always be used. This is true even when another method of birth control is used.

Types of EC

  • Oral medicine
    • Levonorgestrel (available over the counter)
    • Ulipristal acetate (prescription only)
    • A high dose of certain brands of birth control pills (BCPs) can also be used as EC. Talk with your provider to learn more about this option. BCPs require a prescription.

Note: EC can cause side effects in some women when used. These can include nausea, vomiting, tender breasts, and headaches. If needed, medicine can be bought over the counter or prescribed to help prevent nausea and vomiting. Talk with a healthcare provider or a pharmacist to learn more.

  • Insertion of a copper intrauterine device (IUD)
    • When an IUD is used as a form of EC, it must be placed into the uterus by a trained healthcare provider within 5 days after having unprotected sex. The IUD can be removed after your next period. Or it can be left in place for ongoing birth control. Talk with your provider to learn more.

How well EC works

When used correctly, EC works very well to prevent pregnancy. It is most effective when taken as soon as possible after unprotected sex or suspected failure of birth control. Ideally, EC should be taken within 72 hours. But it can be used up to 120 hours after sex. For exact efficacy rates of different types of EC, ask a healthcare provider or pharmacist.

Home care

  • Take EC exactly as directed.
  • If you do not get your period in 3 weeks, use a home pregnancy test or see a healthcare provider to find out if you are pregnant.
  • If you have sex before your next period starts, be sure to use another birth control method.
  • If you are not using birth control regularly, see a healthcare to learn more about your options. You may also go to a local family planning clinic.
  • Do not rely on EC as a form a regular birth control.

Follow-up care

Follow up with your healthcare provider, if needed.

When to seek medical advice

Call your healthcare provider right away if any of these occur:

  • You throw up (vomit) within 3 hours of taking EC.
  • You have severe side effects from taking EC.
  • You have fever of 100.4?F (38?C) or higher, or as directed by the provider.
  • You have irregular vaginal bleeding.
  • You have heavy vaginal bleeding (soaking 1 pad an hour for 3 hours).
  • You feel weak, dizzy, or faint when standing.


To learn more about EC, go to the following website:

Office on Women's Health, US Department of Health and Human Services