How does emergency contraception work?

Several. It may prevent or delay ovulation, interfere with fertilization, or prevent implantation.
ECP's may. delay release of an egg from an ovary, prevent fertilization or prevent a fertilized egg from attaching to the uterus.

Related Questions

How well does emergency contraception work to prevent pregnancy?

89 % Plan b or emergency hormonal contraception is almost 90% effective if it is used within 72 hours of intercourse, and there has only been one ejaculation in that time frame. Read more...
It can be very. effective depending on when it is taken. Here is an example > Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes. Read more...

How long after sex does emergency contraception work?

72 hours. Plan b - the emergency contraception pill - is indicated to use up to 72 hours after unprotected sex. The earlier you take it the better your chances of preventing pregnancy. I often recommend patients to keep it on hand so they can take it as early as possible after exposure. Read more...
ECP. Emergency Contraception like Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes. Read more...