It is narrated from Sayyiduna Abu Thabit al-Ansari (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The woman with istihadah (irregular bleeding) leaves the prayer during the days of her menstruation, then she takes a ritual bath and prays, and after that she performs ablution for every prayer."
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 19165