Even with the multitude of birth control methods available today, accidents can happen. Condoms can break. Women can forget to take their birth control pills. Couples can get caught up in the heat of passion. In these cases, there is another option for women who do not wish to get pregnant—emergency contraception.

Emergency contraception, or the “morning-after pill,” has been around for more than 25 years. It prevents an estimated 1.7 million unintended pregnancies and 800,000 abortions each year in the United States. Emergency contraception works by delaying or inhibiting ovulation (the release of an egg), stopping fertilization, or preventing implantation. Women using emergency contraception can reduce the risk of pregnancy by 75% to 89% when compared to women who are at risk of pregnancy but do not use emergency contraception. New research conducted by the World Health Organization provides further insight into the pros and cons of two methods of oral emergency contraception: levonorgestrel and mifepristone.

When You May Want Emergency Contraception

If any of the following occurs during or around the time of sexual intercourse, and you do not wish to become pregnant, you may want to use emergency contraception:

  • Your partner’s condom broke or slipped off
  • You forgot to take your birth control pills
  • Your diaphragm or cervical cap slipped out of place during intercourse
  • You miscalculated your “safe” days
  • You weren’t using any birth control
  • If there is any way semen could have come in contact with your vagina

Types of Oral Emergency Contraception

Yuzpe Regimen

This regimen of emergency contraception uses two doses of oral contraceptive pills that combine estrogen and certain progestin hormones. The two doses are usually taken 12 hours apart, and work best if taken within 72 hours after unprotected sex. A number of birth control pill brands have been shown to be effective.

Levonorgestrel

An emergency contraceptive pill that can prevent pregnancy if taken within 72 hours after unprotected sex. It contains the synthetic hormone (progestin), which is commonly used in birth control pills, and is generally taken in one dose—though sometimes the pill is split into two doses.

Mifepristone

This form of emergency contraception contains an antiprogesterone drug that blocks receptors of progesterone, a key hormone in the establishment and maintenance of human pregnancy. It is generally taken in one dose. This drug is also known at RU-486 or the “abortion pill,” though if mifepristone is given within 72 hours after conception, the chances that implantation will have taken place is remote—meaning it is preventing pregnancy, rather than destroying an intact fetus. While mifepristone is being used as a contraceptive in this case, the fact that it is a known abortifacient may make some women uncomfortable, which is why research looking at other forms of emergency contraception has been undertaken.

What the Research Shows

A multi-center trial described in the December 7, 2002 issue of The Lancet looked at three different regimens for emergency contraception: single-dose mifepristone (10 mg), single-dose levonorgestrel (1.5 mg), or two-dose levonorgestrel (0.75 mg X 2). Researchers at 15 family-planning clinics in China, Finland, Georgia, Hungary, India, Mongolia, Slovenia, Sweden, Switzerland, and the United Kingdom studied 4084 healthy women who were seeking emergency contraception within five days of unprotected sex. These women were randomly assigned to receive one of the three different treatment regimens.

After the treatments, no significant differences in pregnancy rates or side effects were observed, illustrating that all three regimens were very effective for emergency contraception. (The average pregnancy rate was around 1.6%). These results also suggest that a single larger dose of the levonorgestrel was just as effective as two smaller doses of levonorgestrel given 12 hours apart. Women who used the two levonorgestrel regimens generally had an earlier onset of their menstrual periods than those who used mifepristone, which is an advantage because it provides sooner reassurance that an unwanted pregnancy has been avoided.

How This Affects You

Although emergency contraception is not a replacement for the responsible use of regular contraception, it is an important "back-up" method for use when contraception fails or was not used. Emergency contraception is not effective as a regular method of birth control and does not protect against sexually transmitted infections . You may want to consider testing for sexually transmitted infections if there is a possibility that unprotected sex put you at risk.

Emergency contraception is available from private doctors, hospital emergency rooms, and Planned Parenthood, as well as college, public, and women’s health centers. Cost can vary anywhere from under $10 to a couple hundred dollars depending on what method you use and the type of health care provider you see. Contact your health care provider immediately if you have had unprotected intercourse and wish to avoid an unwanted pregnancy.