Is an increase beyond the usual duration of menstruation considered istihada (abnormal bleeding) or menses, and when is the period of purity, and are discharge with streaks of blood between two menstrual periods, and before and after menstruation, considered istihada or menses?

The maximum duration of menstruation, according to the majority of scholars, is fifteen days. Therefore, blood, pink discharge, and discharge with red streaks that occur within this period are considered menstruation. A woman should not perform ghusl until she sees purity. However, if the total number of bleeding days exceeds fifteen days, then the woman is considered to be suffering from irregular bleeding (istihada). Discharge with red streaks between two menstrual periods is not considered menstruation if it does not reach the minimum duration of menstruation (a day and a night), and if there is between it and the previous menstruation the minimum period of purity (fifteen days or thirteen days).