Sunan Ibn Majah, Chapter: The Chapters on Dry Ablution

It was narrated from 'Urwah bin Zubair and 'Amrah bint 'Abdur-Rahman that 'Aishah the wife of the Prophet (saw) said: "Umm Habibah bint Jahsh experienced prolonged non-menstrual bleeding for seven years when she was married to 'Abdur-Rahman bin 'Awf. She complained about that to the Prophet (saw) and the Prophet (saw) said: 'That is not menstruation, rather it is a vein, so when the time of your period comes, leave the prayer, and when it is over, take a bath and perform prayer.'" 'Aishah said: "She used to bathe for every prayer and then perform the prayer. She used to sit in a washtub belonging to her sister Zainab bint Jahsh and the blood would turn the water red." (Sahih)