The chances of pregnancy are very high when the thickness of the uterine lining has already reached 15mm, because after pregnancy it leads to thickening of the uterine lining. Since the fertilized egg has just been deposited in the uterus, the gestational sac is not yet visible through ultrasound, and the diagnosis can be clarified through blood HCG test. If the value of blood HCG is greater than 10mIU/ml, it indicates pregnancy. It is recommended to check again every other day, if it can double the original value, it indicates that the possibility of intrauterine pregnancy is very high. If the pregnancy continues, proper rest should be given and nutrition should also be strengthened. In addition, if the endometrium is 15mm thick and the blood HCG test is negative, it is possible that there is inflammation or lesions in the endometrium, which leads to abnormal thickening of the endometrium, and diagnostic curettage is needed if necessary.