Is the red blood that appears every one or two months, accompanied by back pain after the insertion of a hormonal IUD, considered menstruation, necessitating the abandonment of prayer, fasting, and intercourse, or is it istihada (non-menstrual vaginal bleeding)?

If the blood appears for a period exceeding one day and one night but not exceeding fifteen days, it is menstruation (hayd). However, if its duration is less than one day and one night, or if the interval between it and the previous blood discharge is less than thirteen days, and the total of the two blood discharges and the period between them exceeds fifteen days, then it is irregular bleeding (istihada).