Yahya related to me from Malik from Hisham ibn Urwa from his father that A'isha, the wife of the Prophet (ﷺ) said, "Fatima bint Abu Hubaysh said, 'Messenger of Allah, I never become pure - am I permitted to pray?' The Messenger of Allah (ﷺ) said, 'That is a vein, not menstruation. So when your period approaches, leave off from the prayer, and when its grip leaves, wash the blood from yourself and pray.' "