Aishah narrated:"Fatimah bint Abi-Hubaish came to the Prophet and said: 'O Messenger of Allah! I am a woman who suffers from persistent bleeding and I do not become clean. Shall I give up Salat?' He said: 'No. That is only a bIood vessel, it is not menstruation. When your menstruation begins then leave the Salat. And when it ends, then wash the blood from you and perform Salat

English translation · Jami' at-Tirmidhi