An endometrial thickness of 14 millimeters and no menstrual period is not a normal phenomenon because the endometrium is on the thick side. The thickness of the lining of the uterus changes at different times of the menstrual cycle. For example, the lining of the uterus is thinnest during menstruation and thickest before menstruation, but usually not more than 12 millimeters. Now the ultrasound examination of the endometrium 14 mm, and did not have menstruation, this is not a normal phenomenon, need to consider whether the pregnancy, whether there is endometrial hyperplasia and so on. 1. Pregnancy. Women who are sexually active and find that the uterine lining is 14 millimeters after the menstrual period is delayed need to test the urine with a pregnancy test first to see if they are pregnant. The endometrium is thicker because the endometrium no longer sheds after pregnancy when estrogen levels rise. 2. Endometrial hyperplasia. If there is endometrium without atypical hyperplasia or endometrium with atypical hyperplasia, endometrial thickening may occur. Medications such as progesterone or dexamethasone can be taken first to promote shedding of the endometrium. If the lining of the uterus is still thick after the period has cleared, diagnostic curettage is recommended as endometrial pathology should be ruled out.