Emergency contraception (EC) is like a backup plan for when things don’t go as planned after unprotected sex or if your regular birth control fails. It works in a few different ways depending on the type and when you take it. Sometimes it stops ovulation, other times it prevents the sperm from fertilizing an egg, or it might even stop a fertilized egg from implanting in the uterus. It’s a last-minute safeguard to prevent pregnancy when you need it most.