Increased menstrual flow after the IUD is usually due to increased endometrial fibrinolytic enzyme activity and prostaglandins, intrauterine infection or abnormal position of the IUD. 1. Placement of IUD will cause an increase in endometrial fibrinolytic enzyme activity and prostaglandins, resulting in increased menstrual flow because the blood is not easily coagulated. 2. Placement of IUD has intrauterine operation, due to localized injury or failure to pay attention to hygiene after the operation, it is easy to lead to upstream infection, causing increased menstrual flow. 3. For long-term placement of IUD with particularly heavy menstrual flow, it is also necessary to consider whether the position of the IUD has shifted downward, partially embedded and other reasons. 4. Pathological changes in the uterus or endometrium, such as endometrial polyps, fibroids, etc., are likely to cause increased menstrual flow after placing the IUD. If the menstrual flow is still heavy more than six months after the placement, and there is a drop in hemoglobin, you can consider removing it. If the menstrual flow increases after the IUD is placed, it is recommended to go to the hospital for examination to rule out other abnormalities causing the increase in menstrual flow, and to give standardized treatment under the guidance of the doctor.