Uterine adhesions generally depend on the location and size of the adhesions. If the adhesion site is located in the center of the uterine cavity or the adhesion area is large, ultrasound is easy to detect; on the contrary, if the adhesion site is hidden, near the edge of the uterine cavity or the adhesion site is small, ultrasound is called difficult to detect. The most common causes of uterine adhesions are endometritis and post-cleansing surgery. In the early stage of endometritis, the endometrium is thickened, the echogenicity is reduced, and a small amount of fluid will appear in the uterine cavity. As the inflammatory infection worsens, the lining of the uterus will slowly become thinner and the menstrual flow will decrease significantly. If there is a secondary infection after the removal of the uterus, the lining of the uterus will not be repaired properly, and the uterine cavity will be adherent, and the ultrasound will show that the lining of the adherent area is thinned or even interrupted. If the diagnosis of uterine adhesions is made, a hysteroscopy is sufficient.