While copper IUDs may increase menstrual bleeding and result in more painful cramps[10] hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether.[7] Cramping can be treated with NSAIDs.[11] Other potential complications include expulsion (2–5%) and rarely perforation of the uterus (less than 0.7%).[7][11] A previous model of the intrauterine device (the Dalkon shield) was associated with an increased risk of pelvic inflammatory disease; however, the risk is not affected with current models in those without sexually transmitted infections around the time of insertion.[12]