Plan B delays ovulation for about five days, according to Choice to Live With. Plan B, also known as the morning-after pill, is a form of oral medication that serves as emergency contraception. It is taken after unprotected sex to prevent unwanted pregnancy.
Plan B includes two pills that contain hormones to delay the ovaries from releasing an egg, notes Choice to Live With. The first pill is taken up to 72 hours following intercourse. The second pill is taken 12 hours after the first pill. Plan B is available over the counter for people at least 18 years old. People younger than 18 need a prescription to get Plan B. Nausea is the most common side effect of Plan B, according to the McKinley Health Center at the University of Illinois.