Hello, unwanted 72 works if it taken with in 72 hrs of unprotected intercourse. If taken in first 24hrs of unprotected intercourse there is 95 % chances of it preventing pregnancy. And if the intercourse is away from ovulation period then there is less chances of her getting pregnant. If she is worried much get her one urine pregnancy test, can be done at home with pregnancy kit. It else visit gynecologist.