Musannaf Ibn Abi Shayba 1:1368

1368. Abda bin Sulayman narrated to us, from Hisham, from his father, from Zaynab bint Umm Salama, who said: I saw the daughter of Jahsh, and she was experiencing istihada (prolonged non-menstrual bleeding). She would emerge from the washbasin while the blood was overcoming her, and then she would pray.