It is narrated from Hazrat Aisha (may Allah be pleased with her) that once, during the night, my menstruation suddenly started while I was lying beside the Prophet (peace and blessings be upon him). So I moved away. The Prophet (peace and blessings be upon him) asked, "What happened? Have your days of nifas (postnatal bleeding) started?" 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."