Thickening of the lining of the posterior wall of the uterus may cause endometriosis, menstrual disorders, affect the implantation of fertilized eggs and other adverse effects. 1. Endometrial lesions: If the endometrial lining of the posterior uterine wall continues to thicken under the effect of estrogen, it may cause abnormal endometrial hyperplasia, endometrial cancer and other lesions. 2. Menstrual disorders: for women with thickening of the endometrium at the back wall of the uterus, they may have heavy menstrual flow, prolonged menstrual period, etc. At the same time, due to the irregular peeling off of the thickened endometrium, there may be a small amount of irregular vaginal bleeding. 3. Affecting the implantation of fertilized egg: thickening of the endometrium will affect the normal implantation of fertilized egg, which will lead to female infertility. For women who are found to have thickening of the lining of the back wall of the uterus, it is recommended that they have a repeat ultrasound after their menstrual period, and if the lining is still thick, it is recommended that they go to the gynecology department of a regular hospital, and if necessary, they will need to have a scraping or have a hysteroscopic examination.