Emergency Contraception

Emergency contraception may be used to prevent pregnancy for a short period of time after unprotected sex.

Emergency contraception decreases the chance of pregnancy after one episode of unprotected intercourse, including when the act occurs near the time the egg is released (ovulation)—when conception is most likely. Overall, the chance of pregnancy is about 5% after one episode of unprotected sex, but closer to ovulation, it is about 20 to 30%. The sooner emergency contraception is used, the more likely it is to be effective.

Available options for emergency contraception include medications taken by mouth and a coppercopperintrauterine device is the most effective form of emergency contraception. The copper IUD prevents the fertilized egg from implanting in the uterus.

• Insertion of a copper IUD: To be effective, the IUD must be inserted within 5 days of unprotected sex or, if the time of ovulation can be estimated, within 5 days of ovulation (release of an egg from the ovary). The chance of pregnancy after insertion of the IUD is 0.1%—the same as it is when the IUD is used for regular birth control. Also, after its insertion, the IUD can be left in place to provide continued contraception for up to 10 years. The effectiveness of a copper IUD as emergency contraception is not affected by weight. Thus, in women who are obese who strongly desire to avoid pregnancy, the copper IUD is the preferred method for emergency contraception.

• To be effective, this IUD should be inserted within 5 days of unprotected sex or, if the time of ovulation can be estimated, within 5 days of ovulation. The chance for pregnancy after insertion of this IUD is 0.3%.

• Yuzpe method:estrogen is used. The high dose often causes nausea and sometimes causes vomiting. Doctors may recommend medications that can help prevent nausea and vomiting. This method is less effective than other methods and is used only when women do not have access to other methods. A hormonal contraceptive may be started at the same time. A backup method (such as a condom) is recommended for 7 days after starting to use the hormonal contraceptive.

A pregnancy test is done 2 to 3 weeks after emergency contraception is used to make sure the woman is not pregnant. Resumption of menstrual periods and a negative pregnancy test result confirms that the woman is not pregnant.