It was narrated that 'Aishah said:
"Fatimah bint Abi Hubaish came to the Messenger of Allah and said: 'O Messenger of Allah! I am a woman who bleeds continuously and never becomes pure, should I give up the prayer?' He said: 'No, rather that is a vein and it is not menstruation. When the time of your period comes, leave off the prayer, and when it is over, take a bath and wash the blood from yourself and perform the prayer." This is the Hadith of Waki'.