What is the ruling regarding blood that appears before the fifteenth day of purity and continues until after the fifteenth day? Is it considered menstruation if it ceases at fifteen days of purity, or is it irregular bleeding (dam fasad)? What is the ruling regarding previous prayers performed based on the assumption that the bleeding was post-partum hemorrhage (istihadah) or irregular bleeding, especially with doubt about the correctness of that assumption?

The shortest period of purity between two menstruations is thirteen days according to the Hanbalis, and fifteen days according to the majority of scholars. So, if a woman sees blood after a period shorter than the minimum purity between two menstruations, and it is not possible to combine it with what preceded it, then she is considered to have Istihada (non-menstrual vaginal bleeding). She should then refer to her previous habit, or act based on valid discernment. If she cannot discern, she should estimate six or seven days of the month by investigation.

As for the prayers she missed, thinking she was menstruating, it is more cautious to make them up, and this is the opinion of the majority of scholars.