Sunan An-Nasa'i

It was narrated that 'Aishah said:""Fatimah bint Abi Hubaish suffered from Istihadah and she asked the Prophet (ﷺ): 'O Messenger of Allah, I suffer from Istihadah and 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 goes wash the traces of blood from yourself and do Wudu'. That is a vein and is not menstruation.'"" It was said to him (one of the narrators): ""What about Ghusl?"" He said: ""No one is in doubt about that