Is the light pinkish discharge, which appeared before the usual period after the insertion of an IUD, and was followed by heavy bleeding as usual, then became light and brownish for more than 15 days, considered istihada ( метроrhagia) thereby permitting prayer, fasting, ghusl, and making up missed prayers?

The maximum duration of menstruation is fifteen days. If the bleeding lasts for fifteen days and does not exceed it, then all of it is considered menstruation. However, if the bleeding and any interspersed purity exceed fifteen days, then it is considered istihada (non-menstrual bleeding). The prayers of the days that were thought to be menstruation but later turned out to be otherwise must be made up. If she sees purity followed by a brownish or yellowish discharge that is not during her customary period, it is not considered menstruation.