It is narrated from Sayyidah Aishah (may Allah be pleased with her) that Fatimah bint Abi Hubaysh (may Allah be pleased with her) asked the Prophet (peace and blessings be upon him): I have istihadah and do not become pure; should I leave prayer? He (peace and blessings be upon him) said: "That is a vein, not menstruation. When menstruation comes, leave prayer; and when it goes, wash the blood from your body, perform ablution and pray. It is from a vein, not menstruation."
In one narration: Fatimah bint Abi Hubaysh (may Allah be pleased with her) asked the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Wash the blood off yourself, perform ablution and pray."
Muslim recorded it without the words "and perform ablution", as though he considered them weak because they contradict the rest of the narrators from Hisham.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1622