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    How Does Emergency Contraception Work?

    When you think you need emergency contraception, you need answers fast. The good news is you have a lot of reliable options that can help if you act quickly. Learn more about your choices and how they work.

    Emergency Contraception Explained

    It can help if you just had sex and something went wrong -- you forgot to use protection, you used it incorrectly, or the condom broke, for instance. It's also an important option for women who were forced to have sex.

    By using emergency contraception within 3 days of sex (the sooner, the better), you can dramatically lower your chance of getting pregnant. It may also work up to 5 days after sex, though it won't be as effective.

    How It Works

    Emergency contraception pills use hormones or medications that block pregnancy. Most use the same hormones that are in regular birth control pills.

    The emergency-use pills mainly work by stopping the release of an egg. The pills also may stop sperm from fertilizing the egg. They also may prevent a fertilized egg from implanting in the uterus. If you're already pregnant, most of these pills will have no effect.

    Emergency contraception works well. But you should take it quickly -- preferably within 24 hours of sex. Yes, it's often called the "morning after" pill. But really, the sooner you take it, the more effective it will be. Studies show that if you take emergency contraception within 72 hours of sex, you have only a 1% to 2% chance of getting pregnant.

    Types of Emergency Contraception

    There are several kinds of pills, or an IUD.

    Most of these pills use levonorgestrel, a form of the hormone progesterone. They include:

    You should use these drugs within 72 hours of having sex. They may still work up to 5 days later, but they're less effective with time. There are some differences among them. Plan B One-Step, My Way, and Next Choice One Dose are one pill. Some other generics are two pills that you take at the same time.

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