Elongated menstruation generally refers to prolonged periods, which may be caused by uterine fibroids, pelvic inflammatory disease, endometriosis, as well as other causes such as cervical cancer. 1. Uterine fibroids: the cause of uterine fibroids is not clear, and it is considered to be related to abnormal hormone levels, heredity, stem cell dysfunction and other factors. Patients will have prolonged menstrual period because of increased menstrual flow, prolonged menstrual cycle and non-menstrual bleeding. 2. Pelvic inflammatory disease: Pelvic inflammatory disease is mainly caused by Neisseria gonorrhea, Chlamydia trachomatis infection and other factors. Patients will have symptoms such as increased menstrual flow, prolonged menstrual period, abnormal vaginal bleeding and increased vaginal discharge. 3. Endometriosis: The cause of endometriosis is not yet clear, and it is considered to be caused by heredity, abnormal immune function, and environmental factors. Patients may have prolonged menstrual period, increased menstrual flow and irregular menstrual flow. 4. Others: Cervical cancer, adenomyosis or placement of birth control ring may also lead to prolonged menstruation. It is recommended that women with prolonged menstrual periods need to consult a doctor in time, and can take appropriate measures under the guidance of the doctor.