A 3mm keloid diverticulum is usually a localized defect in the lower uterine incision caused by poor healing of the incision after cesarean section, which requires prompt medical attention once detected. Keloid diverticulum is a relatively common complication of cesarean section, because during cesarean section, the lower part of the uterus is cut open, and then sutured again after delivery of the fetus, if the incision does not heal smoothly, it will form a depression or defect and form a keloid diverticulum, which is usually detected during ultrasound examination, and some patients are asymptomatic and can be treated without any special treatment. Some patients may have unclean discharge after cesarean section, or have irregular menstruation after the return of menstruation, which needs to be treated by hysteroscopic repair of scar diverticulum.