Print Back to List

How Does Plan B Work?

The synthetic (artificial) hormones in the morning after pill are the same hormones used in many birth control pills to prevent pregnancy. The hormone used in Plan B changes the body’s signals so that pregnancy is prevented by temporarily stopping the release of an egg from the ovary, or it may prevent fertilization. It may also prevent a fertilized egg from attaching to the uterus.

The Plan B pill is not effective in terminating an existing pregnancy or an ectopic (tubal) pregnancy.