An endometrial thickness of 0.7cm 2 days before menstruation is generally abnormal. If the lining of the uterus is only 0.7cm 2 days before menstruation it is considered to be a thin lining of the uterus and is generally abnormal. This condition may cause a decrease in menstrual flow. If left untreated, it may also affect the endometrial tolerance, resulting in a lower pregnancy rate. There are many causes of thin endometrium, such as multiple uterine operations, long-term inflammation, etc. At this time, patients may have abnormal menstruation, non-pregnancy, and uterine adhesions. When the patient finds that the endometrium is thinning, she should seek medical treatment; hormone level measurement and ultrasonography are usually needed to identify the cause of the disease and treat the cause of the disease.