How should cases of irregular menstruation be dealt with, such as the cessation of blood flow then its return, or its continuation for more than 14 or 15 days, and must missed prayers be made up in these cases?

Blood seen during a period when it could be menstruation is considered menses. If it appears at a time when it cannot be menstruation, it is considered istihadah (non-menstrual bleeding). The maximum duration for menstruation is fifteen days, and the minimum period of purity between two menstrual cycles is fifteen days according to the majority of scholars. If blood returns after more than fifteen days of its cessation, it is menstruation. If blood returns after less than fifteen days, then either it can be combined with the previous bleeding, making the total duration (two bleedings and a period of purity between them) not exceeding fifteen days, in which case it is menstruation; or it cannot be combined, meaning the total duration exceeds fifteen days, in which case it is istihadah. In the case of istihadah, the woman with istihadah performs ablution after the entry of the prayer time and prays while taking precautions. Missed prayers during the period of istihadah must be made up according to the majority of scholars. The Hanbali school of thought considers blood after the age of fifty to be istihadah, whereas the majority of scholars do not specify a certain age for the maximum duration of menstruation.