Medical Health Encyclopedia

Emergency contraception

Emergency contraception has several potential effects on a woman's reproductive system that could help to decrease her risk of getting pregnant. Emergency contraceptive drugs appear to work primarily by preventing or delaying egg release (ovulation) from the ovaries. They may also slow egg or sperm transport in the fallopian tubes, and they may make the uterine lining less hospitable for implantation of a pregnancy. For example, IUDs are toxic to sperm and change the uterine lining so that implantation is less likely.

Emergency contraception can be used following many different situations of unprotected intercourse including rape, unplanned acts of intercourse, or when a birth control method fails. For instance, emergency contraception can help to prevent pregnancy after a condom breaks, a diaphragm slips out of place, or birth control pills are forgotten.

Emergency contraception is available by prescription only. An IUD requires an office visit, but a telephone call to the health care provider's office is usually all a woman needs to do in order to start emergency contraception medication.

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Some health care providers will provide their patients with a prescription for an emergency contraception drug to keep at home, in case it is needed in the future.

A toll-free hotline (1-888-NOT-2-LATE) is available to get more information about emergency contraception. Operators at this number may also be able to provide contact information for physicians in local areas who prescribe emergency contraception.

The first dose of emergency contraception medications can be taken up to 72 hours after unprotected intercourse. The second dose is taken 12 hours after the first. These drugs are most effective when taken as soon as possible after intercourse.

EFFECTIVENESS:

Oral emergency contraception medications prevent about 75-89% of pregnancies that occur after unprotected sexual intercourse, and they work best if taken as soon as possible after intercourse. Emergency contraception by IUD insertion is even more effective.