Eight or nine days after menstruation, the uterine lining thickness of 12mm, if there is no contraindication to surgery, the general recommendation is to clear the uterus. A woman’s normal endometrial thickness is between 5mm-10mm, so after eight or nine days of menstruation, the endometrial thickness of 12mm, this situation is generally considered to be the endometrial thickening of the endometrium, you need to undergo a scraping examination, which is used to determine the existence of endometrial pathology, and at the same time, it can be used to stop the hemorrhage. In addition to physiological factors before menstruation and medications, such as estradiol valerate tablets and estradiol tablets, endometrial thickening can also be caused by pathological factors, such as endometrial polyps and endometrial cancer. Women are advised to go to regular hospitals for examination and treatment under the guidance of specialists according to the results.