In the U.S., an estimated 2.3 million pregnancies annually are unplanned. Most women who have had unprotected sex have a 30 percent chance of getting pregnant at the most fertile point in their menstrual cycle. Emergency contraceptive pills reduce that chance by 75 percent, to a pregnancy risk of no more than 8 percent.
Side effects are common but last only a few days.
About half of women who use the pills experience nausea, and about 20 percent vomit. Less common are headache, breast tenderness, dizziness, and fluid retention. Since emergency contraception is so brief, almost all women can use it without fear of the side effects usually associated with long-term use of oral contraceptives. He adds that many doctors don't think to bring it up with their patients. Soon after, Gynetics, Inc., a New Jersey pharmaceutical company, announced plans to market emergency contraceptive pills sometime next year.