Is the menstrual period that has become light and irregular after the removal of the copper IUD considered purity, or must one wait for the period to return to its normal state before performing ghusl?

If a woman sees blood at a time when it could be menstruation, she must refrain from prayer, fasting, and all other things that a menstruating woman abstains from, and perform ghusl after it ceases. If the blood reappears within the menstrual period (a maximum of 15 days), she is considered menstruating again and must perform ghusl after it ceases. Thus, any blood she sees during the menstrual period is considered menstruation, unless its duration exceeds fifteen days, in which case she is considered to be experiencing istihada (non-menstrual vaginal bleeding).