Musannaf Ibn Abi Shayba 1:1351

Abu Khalid al-Ahmar narrated to us, from al-Mujalid and Dawud, from al-Sha'bi, who said: I sent my wife to the wife of Masruq, and she asked her about the woman experiencing prolonged non-menstrual bleeding (mustahada). She mentioned from Aisha that she said: She sits for the number of days of her menstrual cycle, then she performs ghusl and performs wudu for every prayer.