What is the ruling on the blood that comes down at the beginning of menstruation due to an IUD, which is in the form of a brownish discharge or pinkish, and is it considered menses for which the rulings of menses apply, or is it istihadah (irregular vaginal bleeding outside of menstruation)?

The rulings of Islamic law are received from the jurists. Accordingly, any blood a woman sees is considered menses, regardless of its color. Furthermore, according to the Hanbalis, brownish and yellowish discharges are considered menses if they occur during the habitual period. So, if a woman sees blood, brownish, or yellowish discharge during the first two days of her habitual period, she is considered to be menstruating. If this discharge stops and she sees dryness, she must perform ghusl (ritual purification bath) and pray. She then becomes menstruating again if the bleeding resumes, until it ceases with the sighting of purity.