Mishkat al-Masabih #519

‘Adi b. Thabit quoted his father as saying that his grandfather (‘Adi's grandfather’s name is given as Dinar by Yahya b. Ma'in) reported the Prophet as saying regarding a woman who has a prolonged flow of blood that she should abandon prayer during as many days as she used to have her courses, then wash, perform ablution for every prayer, fast and pray. Tirmidhi and Abu Dawud transmitted it.