It is narrated from Hazrat Aisha (may Allah be pleased with her) that once, during the night, my menstruation started suddenly while I was lying beside the Prophet (peace and blessings be upon him). So I moved back. The Prophet (peace and blessings be upon him) asked, "What happened? Have your days of postnatal bleeding begun?" She replied, "No, rather my days of menstruation have started." The Prophet (peace and blessings be upon him) said, "Wrap your lower garment well and then come back."