"O Messenger of Allah, I do not become pure, so should I stop praying? He said: "no, that is a vein." - (One of the narrators) Khalid said, in what I read from him - "and it is not menstruation, so when your period comes, stop praying, and when it goes, wash the blood from yourself and pray."
Sunan an-Nasa'i Book 3, Hadith 19
← Previous Hadith 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 the same amount of time as your regular period has passed, then wash the blood from yourself and pray."

Sunan an-Nasa'i Book 3, Hadith 18 Next Hadith → "Umm 'Atiyah said: 'We used not to regard yellowish and brownish discharge as anything important.'"

Sunan an-Nasa'i Book 3, Hadith 20