Hi, Thanks for posting in HCM. I understand your concern. Postinor 2 is an emergency contraceptive pill. It needs to be taken within 72 hours after an episode of unprotected intercourse to prevent unwanted or accidental pregnancy. The pill would prevent pregnancy from happening by causing breakthrough bleeding within 3 weeks from the day of its intake. In case bleeding does not take place by 3 weeks, you need to seek medical attention immediately. The cause for delay in bleeding needs to be known so as to treat it accordingly. Kindly consult Gynecologist for proper evaluation and management without further delay. Hope the information provided would be helpful. All the best.