The morning after pill, also known as Plan B, is a form of emergency birth control that women can use after other forms of birth control have failed or weren't used.
Basics
According to the Mayo Clinic, women don't usually become pregnant until a few days after they've had unprotected sex, so you can take Plan B within 72 hours of intercourse. The morning after pill prevents the sperm from reaching the egg and fertilizing it and prevents the ovaries from releasing eggs.
Types
The morning after pill has the same type of hormones that birth control contains. One type of morning after pill contains levonorgestrel and others contain progestin and estrogen.
Effectiveness
According the Mayo Clinic, the manufacturer claims that Plan B is 80 percent effective in preventing pregnancy after one instance of unprotected sex if taken correctly.
Prescription
If you are 16 years old or younger, you'll need a prescription to get the morning after pill as of 2009; however, if you're 17 or older, you can get it at your local pharmacy.
Warning
Side effects can include nausea, stomach upset, abdominal pain, drowsiness, dizziness and headaches.
