Sayyidah Aishah (may Allah be pleased with her) says: Umm Habibah bint Jahsh (may Allah be pleased with her), who was the wife of Abd al-Rahman bin Awf (may Allah be pleased with him), had prolonged bleeding (istihadah) for seven years. She complained to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "This is not menstruation; rather it is a vein, so take a ritual bath and pray." Aishah (may Allah be pleased with her) says: Then she used to take a ritual bath for every prayer and pray, and she would sit in the tub of her sister Zaynab bint Jahsh (may Allah be pleased with her), and the redness of the blood would rise above the water.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1558