Endometrial thickening is not necessarily a sign of menstruation. In addition to the normal endometrial thickening before menstruation, it can also be seen in the following two special cases of endometrial thickening: 1. Pregnancy: After a woman is pregnant, due to the relatively short time of pregnancy or ectopic pregnancy situation, it can appear that the ultrasound shows endometrial thickening and the patient’s blood or urine test shows pregnancy. In this case, if the pregnancy is relatively short and there is no abnormal vaginal bleeding and abdominal pain, you can continue to observe. If the pregnancy has been longer, or if irregular bleeding or abdominal pain occurs, further ultrasound, blood HCG, progesterone and other dynamic observation is needed. 2. endometrial lesions: such as endometrial inflammation, polyps, submucosal fibroids, or tumor lesions of the endometrium, hysteroscopic scraping or hysteroscopic removal of lesions is needed in a timely manner. The tissue should be sent for pathological examination to clarify the diagnosis.