Chapter on the Rules of Menstruation, Istihadah, and Nifas, and Purification From Them

It is narrated from Ahmad ibn Muhammad, from Ali ibn Al-Hakam, from Dawood, the servant of Abu Al-Mi'za, from someone who informed him, from Abu Abdullah عليه السلام, who said: I asked Imam عليه السلام about a woman who is menstruating, and then her usual period of purity passes while she is still seeing blood. Imam عليه السلام said: "She should add a precautionary day if her menstruation lasts less than ten days. If the blood continues after that, she is considered to be in the state of istihadha (irregular bleeding). If the blood stops, she should perform ghusl and pray."