Inflammation of the vein may also occur, called thrombophlebitis or simply phlebitis. This may be caused by infection, the catheter itself, or the specific fluids or medication being given. Repeated instances of phlebitis can cause scar tissue to build up along a vein. A peripheral IV line cannot be left in the vein indefinitely out of concern for the risk of infection and phlebitis, among other potential complications. However, recent studies have found that there is no increased risk of complications in those whose IVs were replaced only when clinically indicated versus those whose IVs were replaced routinely. If placed with proper aseptic technique, it is not recommended to change a peripheral IV line more frequently than every 72–96 hours.