568 - Ishaq narrated to us, saying: Al-Walid ibn Muslim informed us, saying: I heard al-Awza'i say - regarding a woman experiencing istihada (prolonged non-menstrual bleeding) if she does not know the timing of her women's cycles and had no known days in the past - he said: "We follow this hadith: 'When the menstruation comes, leave the prayer.'"
Al-Awza'i said: "Its arrival is determined by the blackness of the blood, its foul odor, and its alteration; it does not persist in this state upon her, because if it were to persist, it would kill her. So, if the blood turns black, it is menstruation, and if the menstruation retreats and becomes yellowish or murky, she is then in a state of istihada."
Abu Ya'qub said: "In what was narrated by Muhammad ibn 'Amr, from al-Zuhri, from 'Urwah, that the Prophet, may Allah bless him and grant him peace, said to Umm Habibah: 'Indeed, menstrual blood is a black blood that is known' - there is a confirmation of al-Awza'i's statement. Likewise, it was narrated from Ibn 'Abbas that he said to a woman experiencing istihada: 'As for as long as she sees the Bahri (dark, deep-colored) blood, she should leave the prayer, and when it exceeds that, she should perform ghusl and pray.'"
