Emergency Contraception, or EC (commonly known as the 'morning after pill'), is essentially a higher dose of birth control. It can be taken up to 120 hours after unprotected sex, but it's most effective within 72 hours. A lot of women choose to keep a dose of EC in their medicine cabinets in case of unexpected contraceptive failure. You need a prescription for EC. So if you don't want to deal with taking care of this kind of thing under the stress of a pregnancy scare, act preemptively!
There are two types of pills used specifically for emergency contraception: Plan B and Preven.
Plan B is a progestin-only emergency contraceptive. It is safe and effective for most women—it's also approved by the United States Food and Drug Administration.
Find out everything you ever wanted to know about Plan B, including its effectiveness, side effects, and timing information at the official Plan B Emergency Contraception site:
Preven is the 'double dose' method of birth control. Although it is not actually an administration of two birth control pills, it has about the same estrogen-progesterone composition as any typical birth control. Preven is also approved by the United States Food and Drug Administration.
Find out everything you ever wanted to know about Preven at the official Preven site: http://www.preven.com/prodinfo/fastfacts.asp.
There are 21 total brands of oral contraceptives that can be used for Emergency Contraception in the Unites States (Health Services uses Levlen—for more information, see the Health Services page).
For a comprehensive list of these options and information about each of them, see the Princeton University Emergency Contraception website at http://ec.princeton.edu/questions/dose.html.
Still not satisfied? Check out this EC facts sheet at http://www.backupyourbirthcontrol.org/toolkit/print/ec-factsheet.htm
Or just go to http://www.backupyourbirthcontrol.org/ for complete information.