From him, from Uthman bin Isa, from Sama'ah, who said: I asked Imam عليه السلام about a woman who sees blood during pregnancy. Imam عليه السلام said: "She should refrain (from prayer) for the days she used to menstruate. If the blood exceeds the days she used to refrain, she should add three more days as a precaution. After that, she is considered to be in a state of istihadah."