Indiana Family Health Council, Inc.

Emergency Contraceptive Pills (ECPs)
What Is It?	Pills taken after unplanned, unprotected sex to prevent pregnancy.
How Does It Work?	Depending on when in the menstrual cycle ECPs are taken: Prevents ovulation. May prevent implantation of fertilized egg.
How Is It Used?	Plan B: two pills taken at the same time within 120 hours of unprotected sex. (Contain progestin only) Or: Certain birth control pills are taken within 120 hours after unprotected sex, with a second dose of pills exactly 12 hours later. (Contain estrogen and progestin)
How Well Does It Work?	Plan B is up to 89% effective and combined birth control pills are up to 75% effective. The sooner they are taken after unprotected sex the more effective they will be.
What Are Its Main Advantages?	Can be used after unplanned, unprotected sex. Can be used when usual method fails (for example, when a condom breaks). Can be used after rape. Plan B is available over the counter.
What Are Some Possible Problems?	Frequently causes nausea and vomiting. Vomiting may reduce effectiveness. There is less chance of vomiting with Plan B. Should not be used if already pregnant. May change time of next menstrual period (early or late). If period does not begin within 4 weeks of taking ECPs, get a pregnancy test.

Source: Contraceptive Technology: Seventeenth Revised Edition, Hatcher RA, Trussel J., et al., New York, NY; Irvington Publishers, 1998.

This Web site is partially funded by the Department of Health & Human
Services, Public Health Service Title X Family Planning Project.