Related topics: •  Birth Control Pills •  Cervical Cap

Emergency contraception can prevent pregnancy after you've had sex without birth control or after your birth control method has failed -- say, the condom broke or slipped off, your diaphragm got knocked out of place, or you forgot to take your birth control pills. Depending on where you are in your cycle, your chances of becoming pregnant from one episode of intercourse can be as high as 30 percent. Using emergency contraception can reduce your risk of pregnancy by up to 89 percent.

Only one brand of pills -- Plan B -- is specifically sold for emergency contraception, and they should be taken as soon as possible (but always within three days) after having unprotected sex. If you are a woman aged 18 or older, you can obtain Plan B directly from a pharmacist in all 50 states; in other words, you can buy Plan B pills over the counter without a prescription. If you are 17 or younger, contact your pharmacist for further information on availability. (For women 17 and younger, Plan B is available from a pharmacist in 9 states or through a prescription from a doctor; your pharmacist can help you figure out your available options.)

If it's been longer than three days (but less than a week) since you had unprotected sex, you may still be able to avoid pregnancy by having an intrauterine device (IUD) inserted. When the insertion is done in time, an IUD is better than 99 percent effective.

You should take the first dose as soon as possible but no more than three days (72 hours) after having unprotected sex; take the second dose 12 hours after you take the first tablet. According to the manufacturer, the sooner you begin the Plan B regimen, the more effective it is likely to be.

Plan B, which is approved by the U.S. Food and Drug Administration, contains the hormone levonorgestrel, an ingredient found in many birth control pills, but at a higher dose than the amount contained in a single pill. (Unlike many birth control pills, it does not contain estrogen.) The regimen can prevent a pregnancy by temporarily blocking ovulation, interfering with fertilization, or thinning the lining of the uterus to keep a fertilized egg from becoming implanted there.

The pills aren't the same as RU-486, the European "abortion pill," which interrupts an existing pregnancy. Plan B is a back-up method for preventing pregnancy and will not work if you are already pregnant. In addition, it is not meant for routine use, and it doesn't offer any protection against sexually transmitted diseases.

Regular birth-control pills will also work when taken in the right dose, but you should always check with your doctor first. The instructions can be pretty complicated and they vary from brand to brand. You have to make sure that you have enough pills and that you're taking the right ones at the right time, especially if they're the three-phase kind. Also, remember that the last 7 pills in a pack of 28 don't contain any hormones.

Side effects include nausea, abdominal pain, fatigue, and menstrual changes. Taking an over-the-counter antinausea medication an hour before the first dose of pills can reduce the risk of nausea. See your doctor immediately if you have severe leg or abdominal pain, chest pain or shortness of breath, severe headaches or dizziness, loss of vision or trouble speaking, or jaundice. These can indicate a range of rare but serious complications, from blood clots to liver damage.

About 50 percent of women will have a period within a week of taking the pills. If you don't get a period within 21 days or your period is more than a week late, call your doctor -- you may be pregnant. This could be a medical emergency if the egg is implanted in your Fallopian tubes or abdomen.

No. If you're already pregnant, the pills won't work. There's no evidence that taking birth control pills will harm a fetus at all, but it's not a good idea to risk exposing an unborn child to hormones unless you plan to have an abortion.

You may not be a good candidate for the pills if you've ever had breast cancer, any reproductive cancer, a stroke, blood clots in your legs or lungs, diabetes, liver or kidney disease, severe migraines, or high blood pressure. The IUD may not be a good choice for you if you're at risk of sexually transmitted disease because you or your partner has had multiple sexual partners. In such a case, IUD insertion ups your chances of developing pelvic infections, which can lead to infertility if left untreated.

Further Resources

You can get more information -- including the exact doses recommended for each brand of pill, as well as a directory of physicians in your area who are willing to prescribe them -- on the Emergency Contraception Website , which is operated by the Office of Population Research at Princeton University.

References

First published July 15, 1999
Last updated April 24, 2007
Copyright © 1999 Consumer Health Interactive

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