A postmenopausal endometrial lining of 1mm is usually normal. The thickness of the endometrium changes cyclically under the influence of estrogen and progesterone in the body. During a menstrual cycle, the endometrium in the proliferative phase can thicken from about 1mm to 5-8mm, and up to 10-15mm in the secretory phase, followed by atrophy, necrosis and exfoliation of the functional layer of the endometrium in the menstruation phase, which is discharged along with blood through the vagina. After menopause, ovarian function declines and estrogen levels gradually decrease, resulting in atrophy and thinning of the endometrium. Generally, the endometrium of postmenopausal women should be less than 4mm, if it exceeds this range, it should be considered as abnormal endometrial thickening. Diseases that cause abnormal endometrial thickening include endometritis, functional or dysfunctional endometrium, endometrial polyps and endometrial cancer. If you experience symptoms such as irregular vaginal bleeding, abnormal vaginal discharge, lower abdominal pain, etc., you should go to the hospital to find out the cause of the problem and get early treatment, regardless of the thickness of the endometrium.