What is the ruling regarding blood that flows with the same quantity and characteristics after fifteen days, given the psychological and physical hardship in praying in this state, and the doubt concerning the correct calculation of the menstrual cycle days?

The maximum period for post-natal bleeding (nifas) is forty days. Anything beyond that is considered irregular bleeding (istihada), unless it coincides with her regular menstrual cycle, in which case it is considered menstruation (hayd). The maximum period for menstruation is fifteen days. If the bleeding stops within the forty days and then resumes within the same period, it is still considered nifas, which prohibits prayer and fasting. There is a view that the maximum period for nifas is sixty days. Errors in calculation after sincere effort (ijtihad) are excused.