It is supposed to cover up to 72hrs.
emergency pill protects you within 72 hours of unprotected sex. the pill delays the release of an egg and most cases prevents implantation. if you have sex after 24 hours of taking the pill, you are at a risk of getting pregnant since the pill works better within 24 hours of taking it. it is not advisable to take the pill more than once within a month because of its side effects.