The endometrial lining is 10cm thick, which is definitely not normal. The size of a normal uterus is only 5cm x 4cm x 3cm, if the endometrium reaches 10cm, it is definitely abnormal. Generally speaking, the thickest endometrium in clinical practice is 3cm, and if it appears to be 10cm, it is definitely abnormal. The normal thickness of the endometrium is usually 4-18mm, which is 0.4-1.8cm. if the endometrium is 10cm thick, it is quite serious. The thickness of the endometrium varies with the menstrual cycle, and the normal thickness of the endometrium is usually no more than 2 cm, or about 3 cm if there is endometrial disease. If the thickness of the endometrium is 10cm, it is necessary to undergo surgery.