Benefits and Drawbacks

Effectiveness: According to Planned Parenthood and the Reproductive Health Technologies Project, if taken within the first 72 hours of unprotected intercourse, emergency contraceptive pills are 75-89% effective in reducing the risk of pregnancy. The effectiveness rate of 75% does not mean a 25% failure rate. Instead, when considering 100 women who have had unprotected intercourse during the middle 2 weeks of their cycle, about 8 became pregnant. If those 8 had used emergency contraception, only 2 would have become pregnant. Emergency contraception pills work best when used as soon as possible after unprotected sexual intercourse. Planned Parenthood cites emergency IUD insertion as being 99.9% effective.

Advantages: Emergency contraception is a safe form of backup birth control if your birth control fails or if you have unprotected sexual intercourse. It is used after intercourse but before pregnancy has occurred. After use, fertility returns to normal unless a form of birth control is continued.

Disadvantages: Common side effects of emergency contraceptive pills are similar to those of birth control pills. They include nausea, abdominal pain, fatigue, headache, and menstrual changes. Breast tenderness, fluid retention, and dizziness may also occur. Many of these symptoms may be less severe with progestin-only or intrauterine forms of emergency contraception. Serious risks include heart attack, blood clots, and strokes. Emergency contraceptive pills do not continue to protect against pregnancy during the rest of the cycle. Emergency contraception may not prevent tubal pregnancy. If you experience severe abdominal pain, contact your health care provider immediately. Tubal pregnancy can be life threatening. Side effects of IUDs used for emergency contraception are the same as those for ongoing birth control IUDs. Emergency contraception does not protect against sexually transmitted infections, nor does it treat existing infections.

Women who should not use emergency contraception: Women who are pregnant, those with undiagnosed vaginal bleeding, and women with an allergy to the product should not use emergency contraceptive pills. IUD use for emergency contraception is not recommended for women who are not in an established monogamous relationship and those who have been raped. See Birth Control Intrauterine Devices for more information about IUDs.