Musannaf Ibn Abi Shayba 1:1354

Hatim narrated to us, from Abd al-Rahman ibn Harmala, from Sa'id ibn al-Musayyib, regarding the woman who experiences *istihada* (prolonged non-menstrual bleeding) and whose menstruation becomes prolonged: She should perform ghusl and cleanse herself thoroughly. Then, she should place cotton [or a pad] just as the one suffering from a nosebleed places it. She should then bind herself with a cloth and pray.