Buhayyah said: I heard a woman who was (perhaps) asking Sayyidah Aishah (may Allah be pleased with her) about menstruation. Sayyidah Aishah (may Allah be pleased with her) said: I asked the Messenger of Allah (peace and blessings be upon him) about a woman whose menstruation had become irregular and who was bleeding profusely. The Messenger of Allah (peace and blessings be upon him) ordered me "to tell her to wait for as long as she used to menstruate each month, to sit for the extent of those days and leave prayer, then perform ghusl, bind a cloth around herself like a loincloth, and pray."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1621