Is the brown blood that accompanies the use of birth control pills menstruation or istihadah, and is prayer obligatory with it?

If the blood is red and recognizable, it is menstruation if it occurs at its appropriate time. As for the brownish discharge (kudra), it is considered menstruation if it occurs during the accustomed period or if it is connected to the menstrual flow. In the case of Istihadha (non-menstrual vaginal bleeding), one must follow what has been explained in previous fatwas.