First of all, the Plan B(morning after) pill is an emergency contraceptive (a BACKUP method of birth control and NOT FOR ROUTINE use). An emergency contraceptive (meant to be used in an “emergency”) is a method of preventing pregnancy that’s used after another contraceptive used fails or if no protection was used. It works before an egg is released by the ovary(ovulation) by stopping or delaying the release of the egg from the ovary. This pill is available as a non prescription medication(over the counter) and should be taken as soon as possible after the event “within 72 hours” for this to be effective. It’s efficacy might also be affected by body weight. Some other emergency contraceptives options exist that can be used more than 72 hours after but will require a doctor’s clinic visit and prescription, like the Ella and IUD options. PS: Note that the Plan B pill will not work if a person is already pregnant, meaning it will not affect an existing pregnancy. Like + Follow ...