Sayyidah Aishah (may Allah be pleased with her) narrated from the Prophet (peace and blessings be upon him) that he (peace and blessings be upon him) said concerning the woman with istihadah: "She should leave prayer during the days of her menstruation, then perform ghusl once, then perform ablution until the like of her menstrual days (comes again). If she sees yellowness, she should sprinkle water, perform ablution and pray."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحيض / 1626