It was narrated that 'Aishah said:
Fatimah bint Abi Hubaish came to the Messenger of Allah (ﷺ) and said: "I am a woman who suffers from Istihadah (non-menstrual vaginal bleeding) and I never become pure. Should I stop praying?" He said: "No, that is a vein, it is not menstruation. When you period comes, stop praying, and when it goes, wash the blood from yourself and pray."
English reference: Vol. 1, Book 1, Hadith 213
Arabic reference: Book 1, Hadith 214