Diagnosing the cause of uterine bleeding typically involves several steps: 1. Medical History: A thorough medical and menstrual history is taken. 2. Physical Examination: A pelvic exam is conducted to check for abnormalities. 3. Blood Tests: To check for hormonal imbalances or other issues. 4. Imaging Tests: Ultrasound, MRI, or CT scans to visualize the uterus and surrounding structures. 5. Biopsy: Taking a small sample of uterine tissue for laboratory analysis. 6. Hysteroscopy: A procedure where a small camera is inserted into the uterus to look for abnormalities.