An endometrial thickness of between 8 and 12 millimeters at the time of menstruation is normal, and is a normal thickness of the lining of the uterus. With an endometrial thickness in this range, the amount of menstruation will usually be within the normal range as well. If the endometrium is too thin it can cause very little menstruation or take an unusually long time to menstruate, which is usually associated with inflammation of the endometrium, endometrial defects, and uterine manipulation. If the endometrium is too thick, it will also have an effect on the amount of menstruation, which will lead to an increase in the amount of menstruation with blood clots, or even cause hemorrhage, resulting in hemorrhagic shock, functional uterine blood loss, etc. In addition, if the thickness of the endometrium is obviously abnormal, it is also necessary to consider whether there is a malignant lesion of the endometrium. Therefore, when abnormal menstruation occurs, it is necessary to review the ultrasound, and then according to the endometrial condition, as well as the patient’s clinical symptoms, to carry out further treatment and treatment.