Endometrium 19mm may be normal phenomenon, or may be endometrial thickening, need to be judged according to the specific circumstances. 1. Normal phenomenon: Clinical ultrasound suggests that the endometrial thickness is 19mm, which can normally be seen during pregnancy. 2. Endometrial thickening: the thickness of the endometrial lining changes with the menstrual cycle, if it is in the post-ovulatory period or pre-menstrual period, or early pregnancy, the endometrial lining will be thickened, but the thickness of 10mm or so, usually not more than 15mm. The endometrium is 19mm, suggesting that the endometrium is thickened and there may be endometrial pathology, such as precancerous endometrial lesions, endometrial polyps, endometrial cancer, and so on. Therefore, whether the endometrial lining of 19mm is abnormal or not needs to be judged according to the specific situation, and if it is abnormal, consult a doctor as soon as possible for treatment.