Emergency Contraception


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What is emergency contraception?

Emergency contraception is a form of birth control. You can use this method if you have had unprotected sex and are worried that you might get pregnant. For example, if your regular birth control fails (the condom breaks during sex), if you forget to take your birth control pills or if you have sex without using any birth control.

There are 3 types of emergency contraception.

  • Pills that contain levonorgestrel
    • Plan B One-Step: 1 pill to be taken within 72 hours after having unprotected sex
    • Levonorgestrel: 2 pills; the first dose taken within 72 hours of unprotected sex, and the second dose taken 12 hours after the first
    • Next Choice: 2 pills; the first dose taken within 72 hours of unprotected sex, and the second dose taken 12 hours after the first. Both doses can also be taken together and will result in the same effectiveness.
  • A pill that contains ulipristal acetate
    • ella: 1 pill to be taken within 120 hours of having unprotected sex
  • A copper-containing intrauterine device (IUD)
    • Paragard: the IUD placed in your uterus by your doctor within 7 days after unprotected sex.  An IUD is a small device that can be left in your body for 5 to 10 years. It will prevent pregnancy during that time.

The U.S. Food and Drug Administration has also said that some brands of regular birth control pills are safe for emergency use. The number of pills you take in each dose depends on which brand of pills you are using. However, this method is less effective and tends to cause more side effects. To learn more about which pills are safe for emergency use, talk with your doctor.

How does emergency contraception work?

Pills used for emergency contraception can prevent your ovaries from releasing an egg, can prevent an egg from being fertilized by sperm, or can prevent a fertilized egg from attaching itself to the wall of the uterus.

Emergency contraceptive pills are not the same as the medicine known as the "abortion pill." This medicine is taken in the early weeks of pregnancy to end the pregnancy. Pills used as emergency contraception can't end a pregnancy once a fertilized egg has attached itself to the wall of the uterus.

Unlike the morning-after pill, an IUD doesn't stop your ovaries from releasing an egg. The IUD can prevent an egg from being fertilized and it can stop a fertilized egg from attaching itself to the wall of the uterus.

No studies have shown that taking hormones while you are pregnant can hurt your baby. However, if you know you are pregnant, you should not take emergency contraception pills.

How effective is emergency contraception?

Emergency contraceptive pills can be very effective if they are used in time. If used within 72 hours of unprotected sex, it can reduce the risk of pregnancy by 75% to 89%. It is important to remember that these pills will work best when taken as soon as possible after unprotected sex.

Evidence has shown that being significantly overweight or obese can decrease the effectiveness of emergency contraceptives with levonorgestrel, including Plan B One-Step.  Women weighing more than 165 pounds should consider an alternative form of emergency contraceptive, such as ella or IUD.

Emergency IUD insertion is also very effective. It can reduce the risk of pregnancy by 99.9% if inserted within 7 days after unprotected sex.

It is important to remember that using this type of contraception regularly is less effective than using ongoing methods of contraception (like normal birth control pills or diaphragms). Emergency contraception should not be your main type of contraception.

Are there any side effects?

Some women feel sick to their stomach after they take emergency contraceptive pills. This feeling should go away in about 2 days. Your doctor can give you medicine that may help you feel better. Other side effects may include headache, breast tenderness, vaginal bleeding, and abdominal pain.

A possible side effect of an IUD is bleeding between periods. Talk to your doctor to find out more about how IUDs work. You also can read more about IUDs on familydoctor.org.

Who can use emergency contraception?

If you can take regular birth control pills, you should be able to take emergency contraceptive pills. If you are pregnant, have breast cancer, or have had blood clots, you should not use emergency contraceptive pills. Talk with your doctor about whether emergency contraception is right for you.

You should not use an IUD if you have a sexually transmitted infection (STI) or if you have been raped. Talk to your doctor about other options.

When do I need to start taking my regular birth control again?

After you take emergency contraceptive pills, your period may come earlier or later than usual. Call your doctor if you do not get your period within 21 days after taking the pills.

If your regular form of birth control is condoms, spermicides or a diaphragm, you may go back to using them right away after taking emergency contraceptive pills.

If your regular form of birth control is the pill, shot, contraceptive patch or vaginal ring, talk to your doctor about when to start using it again.

Where can I get emergency contraception?

Talk to your doctor about how to get emergency contraception, or about having a prescription on hand in case you need it. You also may be able to get emergency contraception from university and women's health centers, health departments, Planned Parenthood centers, and hospital emergency departments.

Plan B One-Step is now available in most U.S. pharmacies without a prescription. However, in some locations you may need to ask the pharmacist for the medicine.

Written by familydoctor.org editorial staff

Reviewed/Updated: 12/13
Created: 10/04

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