There's a lot of information out there about the morning-after pill -- some of it good, some of it not so good, and some of it flat-out wrong. Here is a description of what the morning-after pill is and how it works, based on information from trusted health resources such as the federal government's Department of Health and Human Services and About.com's Women's Health website.
The morning-after pill, one type of emergency contraception (EC), is a type of birth control pill doctors prescribe in emergencies, such as when a condom breaks, after a sexual assault occurs, or when a woman forgets to take her regular birth control pills. If taken within 72 hours of sexual intercourse, the morning-after pill prevents sperm from fertilizing eggs.
Morning-after pills prescribed in the United States, such as Plan B and Preven, will not end a pregnancy that has already happened: Therefore, they are not abortion pills. Like other birth control pills, they use hormones to keep sperm away from eggs in the first place.
The morning-after pill and other forms of emergency contraception may be obtained from many doctors and nurse practitioners, including those that work at women's health clinics such as Planned Parenthood.