Patient Education

Emergency Contraception

Emergency contraception is used to prevent an unwanted pregnancy after having unprotected sex or birth control failure.  Although it is generally effective, emergency contraception should not be used as a birth control method.  This page provides basic information about emergency contraception and how it works.


Emergency contraception should be used after you have had unprotected sex but do not want a child. You may need emergency contraception if:

  • You didn’t use any birth control
  • You didn't use your birth control correctly
  • You were forced to have sex
  • You didn’t plan on having sex
  • A condom broke or slipped off
  • Your diaphragm slipped out of place

Timing is important, and emergency contraception should be started as early as possible.  It most likely delays ovulation to prevent a pregnancy.  It does not end an existing pregnancy.  You should not use emergency contraception in pill form if you know you are pregnant.  Emergency contraception is available in doctor’s offices, family planning clinics, hospitals, and some drug stores.


  • Pills: Pills are the most common form of emergency contraception. They work in different ways: by delaying ovulation, by blocking fertilization, or by keeping a fertilized egg from implanting in the lining of the uterus. Plan B One-Step is one pill, taken within 72 hours/3 days of unprotected sex. This is available without a prescription at pharmacies if you are 17 or older. (If you are under 17 you will need a prescription from a health care provider.) Ella is one pill that can be taken within 120 hours/5 days of unprotected sex. (Approved by the FDA 8/2010). Another option is to take specific doses of birth control pills. The number depends on the pill taken, and you need a prescription for this method. After taking emergency contraceptive pills, it is normal to experience some temporary side effects like nausea, headache, breast tenderness, fatigue or dizziness. Nausea is more likely if you take doses of birth control pills rather than the single pill option. If your period is more than one week late, you should take a pregnancy test.
  • Intra-Uterine Device: IUDs are another form of emergency contraception. The IUD must be inserted by a provider within 5 to 7 days of having unprotected sex. An advantage of an IUD is that it can provide 5 to 10 years of birth control once it is in place.


When taken correctly, emergency contraception will prevent about 75% of pregnancies that would have occurred in women not using any birth control. However, it is not as effective as birth control methods. Ask your provider about a regular method of birth control and other ways to protect yourself against sexually transmitted diseases.


Using an effective method of birth control before having sex is the best way to prevent unwanted pregnancies. Fortunately, emergency contraception is available to women who have had unprotected sex for any reason. Either pick up Plan B One-Step or Ella at your pharmacy, or call your provider for further advice or treatment options. Remember, timing is important so act quickly for the best results.