I.

Introduction

Emergency Contraception, also called postcoital contraception, method of preventing pregnancy after unprotected vaginal intercourse. Women may choose to use this form of birth control in any situation where unprotected intercourse has occurred and a pregnancy is not desired—for example, when a male condom breaks or slips off, a female condom becomes dislodged, or a diaphragm or cervical cap slips out of place during sex; when a woman forgets to take regularly prescribed birth control pills; or a woman is forced to have unprotected vaginal intercourse against her will. Emergency contraception takes two forms: the administration of emergency contraceptive pills (ECPs), which contain high doses of female sex hormones, or the insertion of a copper intrauterine device (IUD) in the uterus.

II.

Emergency Contraceptive Pills

There are two types of ECPs, also known as morning-after pills. One type contains a combination of the female sex hormones estrogen and progestin (formerly marketed under the brand name Preven but no longer available on the United States market). A second type of ECP contains only progestin (marketed as Plan B). The hormones in ECPs prevent an egg from being fertilized by sperm, either by delaying or preventing ovulation, or by affecting the ability of sperm to reach the egg. These hormones may also prevent an egg from implanting in the uterus. ECPs should not be confused with mifepristone (commonly known as RU-486), a drug that prevents pregnancy but also causes abortion when taken within the first seven weeks of pregnancy. ECPs do not cause abortions.

In 2006 the Food and Drug Administration (FDA) approved pharmacy-only nonprescription sales of ECPs (Plan B) for women 18 and older. Teenage girls 17 and younger need a prescription from a doctor to obtain the drug. Pharmacists must make a photo identification check. A woman takes ECPs in two doses. She ingests the first dose as soon as possible after unprotected intercourse, but within five days. The second dose is taken 12 hours later. The pills are most effective when taken within 72 hours of unprotected intercourse, and least effective in women who are close to ovulating. Most women begin to bleed from their menstrual cycle within two to three weeks after taking ECPs.

With typical use, combination ECPs reduce the risk of pregnancy by 75 percent, while progestin-only pills reduce the risk by 89 percent. ECPs are effective only against the current episode of unprotected intercourse—they do not provide birth control for the remainder of the woman’s menstrual cycle.

ECPs are easy to use and do not affect a woman’s ability to become pregnant in the future. If mistakenly taken by a pregnant woman, these pills do not cause birth defects. Women who are at increased risk for stroke, heart attack, or blood clots when taking hormonal contraceptives such as birth control pills can safely use ECPs.

ECPs do not protect against sexually transmitted infections, including human immunodeficiency virus, the cause of acquired immunodeficiency syndrome (AIDS). Women who take combination ECPs may experience nausea, vomiting, breast tenderness, fatigue, irregular bleeding, abdominal pain, headaches, fluid retention, and dizziness. These side effects usually disappear within a few days after ingesting the second dose of pills. Progestin-only ECPs cause fewer side effects than do combination ECPs.

III.

Intrauterine Device

Another form of emergency contraception is the insertion of a copper IUD. A trained health-care professional must insert the device, which is guided through the vagina into the uterus. In addition to triggering an immune response that disables sperm and eggs, the IUD releases copper, which kills sperm. Although the IUD can be removed after the woman’s next menstrual period, it can also be left in place for up to ten years to provide continuous protection against pregnancy. When inserted within five days of unprotected sex, the copper IUD is 99 percent effective in preventing pregnancy.

The use of a copper IUD for emergency contraception is not recommended for women with sexually transmitted infections or pelvic inflammatory disease. Women with multiple sexual partners, new partners, or who have been sexually assaulted should not use an IUD because of the risk of spreading undiagnosed infections to the uterus when the IUD is inserted. In some women, an IUD may cause abdominal pain, irregular vaginal bleeding, heavy periods, cramping, and infertility. Women who plan to become pregnant in the future may want to use ECPs instead of an IUD. In rare cases an IUD can also puncture the uterus, leading to severe health complications.