If ultrasound examination reveals a 0.3 cm separation of the uterine cavity, it may be caused by the following reasons: 1. After abortion, medication abortion, or diagnostic curettage, there is still residual blood in the uterus after the operation of the uterine cavity, so that the uterine cavity is separated. It is recommended to combine the clinical history with a comprehensive analysis, separate the adhesions in the posterior fornix if necessary, and then discharge the pus from the uterine cavity and give a large amount of antibiotics for treatment.