Note: Information provided on this page is for general education only, please seek medical assistance when in doubt
Emergency contraceptive methods are medications or devices used after unprotected sexual intercourse with a hope of preventing unwanted pregnancy. They are sometime also referred as morning-after pills.
Emergency contraceptives work primarily by preventing ovulation or fertilization. A number of pills exist including high dose birth control pills, levonorgestrel, mifepristone, ulipristal and IUDs.
Levonorgestrel pills, when used within 3 days, decrease the chance of pregnancy after a single episode of unprotected sex or condom failure by about 70% which results in overall pregnancy rate of about 2.2%.
Ulipristal, when used within 5 days, decreases the chance of pregnancy by about 85% which results in overall pregnancy rate of about 1.4% and generally considered to be a little more effective than levonorgestrel.
Mifepristone is also more effective than levonorgestrel while copper IUDs are the most effective method. IUDs can be inserted up to five days after intercourse and prevents about 99% of pregnancies after an episode of unprotected sex which results in overall pregnancy rate of about 0.1 to 0.2% which simply makes it the most effective form of emergency contraceptive.
In those who are overweight or obese levonorgestrel is less effective and an IUD or ulipristal is generally recommended.
Emergency contraceptive pills do not affect rate of sexually transmitted infections, and should be used as a method for birth control only. To prevent sexually transmitted infections use of condom is generally recommended.
Emergency contraceptive methods do have some side effects.