Instructions for Using the Morning-After Pill

Choosing, Using, and Timing It Right

Morning after pill
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The morning-after pill is a type of emergency contraceptive that you can take if you have unprotected sex or you suspect the birth control method you used may have failed – you and your partner used a condom and it broke, for example.

Types of Morning-After Pills and How They Work

There are a variety of morning-after pills on the market, such as Plan B One-Step and Next Choice One Dose, but all work the same way. Each consists of one pill containing 1.5 milligrams of a medication called levonorgestrel, a progestin that prevents sperm from fertilizing an egg, and that also may change the lining of the uterus so that even if an egg does get fertilized it won't be able to implant.

Effectiveness of the Morning-After Pill

The morning-after pill works 84 percent to 89 percent of the time, but timing is important: It's most effective when taken within 24 hours, but you can still use it within three days after having sex. Whether it works for you or not depends in part on two things:

  • The amount of time that has gone by since you had sex – in other words, the sooner you take the pill, the more likely it is to keep you from getting pregnant.
  • The point in your cycle when you had sex. The closer you are to ovulation, the less effective the morning-after pill will be.

What to Expect After Taking the Morning-After Pill

If you find yourself in need of emergency contraception, choosing and using the morning-after pill is easy. Generic versions of the drug are just as safe and effective as brand names but do check the expiration date. It goes without saying, but don't buy a drug that has expired. Find another brand or ask the pharmacist for help.

You can take the pill at any time of time of day. Again, the sooner the better. In fact, it may be a good idea to have a package of the morning-after pill on hand so you can use it as quickly as possible if the need arises, rather than take time to go to the store. To make sure it will be effective, store it at room temperature and if you don't use it before it expires, toss it and replace it with a new one.

Do read the directions and package insert first, especially so you know how you may feel after. Thousands of women have taken the morning-pill with no serious complications, but there are some common minor side-effects:

  • Nausea or vomiting (you may be able to avoid this by taking an over-the-counter nausea drug an hour before you take the morning-after pill)
  • Breast tenderness
  • Headache
  • Pain in the lower part of your abdomen
  • Fatigue
  • Dizziness

Taking the morning-after pill may affect your menstrual cycle, causing you to spot or have irregular bleeding before your next period, for example. It also can delay your period or cause it to come sooner than expected, although it will likely be within a week of your usual time. You may have a heavier or lighter flow. Of course, if your period is more than a week late, it may mean the pill didn't work for you. Take a home pregnancy test right away to be sure.

If any other adverse reactions occur after using the morning-after pill, you should call your doctor. You may also want to consult with your doctor if your scheduled period is more than seven days late, as this may indicate that you could be pregnant.

If you develop severe abdominal pain three to five weeks after using the morning-after pill, you may have an ectopic pregnancy, in which a fertilized egg implants somewhere other than the uterus. This can have serious complications, so see your doctor right away.

How Long the Morning-After Pill Lasts

If the morning-after pill prevented you from getting pregnant, it's done its job. But remember that the pill won't continue to be effective. After you use it, your fertility will return, so don't take a chance and have unprotected sex. Be vigilant about using birth control. 

Don't, however, treat the morning-after pill as a regular form of birth control. If you keep having unprotected sex and following up with the morning-after pill, your periods could become irregular and unpredictable.

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