The thickness of the double layer of the endometrium is usually no more than 13 millimeters, and a thickness of 20 millimeters is usually the result of diseases such as functional endometrial bleeding and endometrial cancer. Endometrial thickness of 20 mm is commonly seen in menopausal functional endometrial bleeding and pubertal functional uterine bleeding. This is due to unstable hormone secretion and luteal insufficiency in the female body, so the endometrium is continuously stimulated by estrogen and will proliferate over a long period of time, resulting in the thickening of the endometrium. The possibility of endometrial cancer should also be ruled out, which will also cause prolonged irregular bleeding from the vagina, and it is recommended to go to the hospital for diagnostic scraping and pathologic examination. If the above symptoms occur, it is recommended to go to the hospital in time for early and regular treatment.