It was narrated that 'Aishah said:"Fatimah bint Abi Hubaish said to the Messenger of Allah (ﷺ): 'O Messenger of Allah (ﷺ), I do not become pure. Should I stop praying?' The Messenger of Allah (ﷺ) said: 'That is a vein and is not menstruation. When your period comes, stop praying, and when it has passed, then wash the blood from yourself and pray

English translation · Sunan an-Nasa'i