Adenomyosis, or adenomyosis of the uterus, is of unknown etiology, but may be related to the invasion of the basal endometrium into the myometrium as a result of uterine operations and endometrial inflammation. 1. Transuterine operations: Transuterine operations or surgeries such as diagnostic curettage, abortion or labor and delivery, cesarean section, etc., may induce the endometrium to invade the myometrium, thus leading to adenomyosis. 2. Inflammation of the uterine lining: mainly seen in chronic endometritis, which is closely related to the development of adenomyosis. 3. Others: It can also be seen in factors such as hyperestrogenemia and heredity, which are also high-risk factors for the occurrence of adenomyosis. When adenomyosis occurs, it is recommended to go to a regular hospital for diagnosis and treatment to avoid delaying the condition.