Postinor 2 is an emergency contraceptive pill designed to prevent pregnancy after unprotected sexual intercourse or contraceptive failure. It contains levonorgestrel, a synthetic hormone that works primarily by preventing ovulation. Postinor 2 is most effective when taken as soon as possible after intercourse, ideally within 72 hours. This medication does not protect against sexually transmitted infections (STIs) and should not be used as a regular form of birth control. Always consult a healthcare professional for personalized advice.