Irregular menstruation at the age of 49, sometimes for ten days and sometimes for forty days, may be caused by perimenopausal syndrome, endometrial polyps, endometrial cancer and other diseases, as well as uterine fibroids, cervical cancer, ovarian cancer and other diseases. 1. Perimenopausal syndrome: Perimenopausal syndrome is caused by the endocrine system changes in the body due to the failure of ovarian function in women, and the main symptoms of patients are irregular menstrual cycle, menopause, hot flashes, anxiety, etc. Therefore, women at the age of 49 years old will have irregular menstruation for sometimes more than ten days and sometimes more than forty days. 2. Endometrial polyps: endometrial polyps are considered to be caused by high estrogen levels or inflammatory stimulation, and the main symptoms of patients are abnormal menstruation, non-menstrual bleeding, and foul-smelling secretions. Therefore, 49-year-old women will have symptoms of irregular menstruation sometimes for ten days and sometimes for forty days. 3. Endometrial cancer: endometrial cancer is caused by excessive stimulation of endometrium by estrogen, and the typical symptoms of patients are abnormal vaginal bleeding, menstrual disorders, abnormal vaginal discharge, etc. Therefore, 49-year-old women will have irregular menstruation sometimes for ten days and sometimes for forty days. 4. Other: uterine fibroids, cervical cancer, ovarian cancer and other diseases may also cause 49-year-old women to have irregular menstruation sometimes for ten days and sometimes for forty days. Therefore, it is recommended that 49-year-old women with irregular menstruation should consult a doctor in time to find out the cause of the disease and treat it under the doctor’s guidance.