Endometrial thickness varies in 1 menstrual cycle, in the follicular phase when the endometrium is relatively thin, if the menstrual period has just cleaned up, the endometrium 0.5cm normal, with the growth of follicles, the endometrium will gradually thicken, until the follicle is mature if the endometrium is still 0.5cm, that is, the endometrium is too thin to be able to get pregnant. Under normal circumstances, when the endometrium reaches 0.8cm at the time of ovulation, it has no effect on pregnancy. If the thickness of the endometrium is within 0.4cm after menopause, if it is more than 0.5cm, it is not normal and needs to be closely observed. When irregular vaginal bleeding occurs, it is necessary to scrape the uterus for pathologic examination to prevent pre-cancerous lesions in the uterine cavity.