Hormonal birth control mimics estrogen and progesterone and prevents pregnancy by: stopping the ovary from releasing an egg (ovulation); thinning the uterus lining to prevent a fertilized egg from implanting in the uterus lining; and thickening cervical mucous to prevent the sperm from entering the uterus.

Barrier birth control methods block the sperm and egg from meeting.

Even if birth control is used, accidents can happen, but it’s still possible to prevent pregnancy with emergency contraception (EC).