Are the days in which the brownish discharge (kudra) appears two or three days before menstruation considered part of the menstrual period, or are they considered a state of purity during which prayer is obligatory?

The brownish discharge that precedes menstruation is not considered menses by many scholars, and a woman is not considered to be menstruating unless she sees clear blood. She remains in that state until the bleeding stops, along with any yellowish or brownish discharge that follows it.