Effectiveness
Progestin-only EC reduces the risk of pregnancy by 89 percent if started within 72 hours of unprotected intercourse. For example, eight out of 100 women will become pregnant after having unprotected sex once during the second or third week of their cycles. But only one woman out of 100 will become pregnant after taking progestin-only EC.
Combination EC reduces the risk of pregnancy by 75 percent if started within 72 hours of unprotected intercourse. Only two out of 100 will become pregnant after taking combination EC.
Emergency contraception is meant as backup birth control only. EC is not as effective as the correct and consistent use of reversible contraception the IUD, the shot, the pill, the patch, or the ring.EC does not continue to prevent pregnancy during the rest of the cycle. Other methods of birth control must be used.
Emergency contraception offers no protection against sexually transmitted infections. You may want to consider testing for sexually transmitted infections if there is a possibility that unprotected sex put you at risk.
