A method of contracep討on that can be taken after unprotected sex to prevent pregnancy. It works by delaying ovulation in that cycle. It may also prevent a fertilized egg from implanting in the uterus.
Advantages
Up to 85% effective if taken with 3 days (72 hrs).
Can be used in times of emergency eg incase of rape.
Can be used incase of failure of a regular method of contraception eg when a pill is forgotten or a condom breaks.
Disadvantages
Should not be used as a regular form of contraception
It does not disrupt an implantation that has already taken place.