Prolonged menstrual period may be caused by endocrine disorders, gynecological inflammation and endometrial abnormality. 1. Endocrine disorders: such as abnormal ovarian function, ovulation disorders and abnormal thyroid function may lead to endocrine disorders, resulting in prolonged menstrual period. 2. Gynecological inflammation: such as pelvic inflammatory disease, due to inflammatory stimulation leading to pelvic congestion and edema, increased vascular fragility, mainly manifested in prolonged menstrual period and increased menstrual flow. 3. Endometrial abnormality: endometrial polyp, endometrial hyperplasia, endometrial cancer, etc., can lead to prolonged menstrual period. In addition, uterine fibroids, submucosal fibroids or intermural fibroids protrude into the surface of the uterine cavity, which increases the area of the endometrium, and prolonged menstruation occurs. Patients with prolonged menstrual periods should go to the gynecology department of regular hospitals in time to find out the cause of the disease and under the guidance of professional doctors for targeted treatment.