My son has the same problem. Later finding out that it is very common in kids. What's happening is, her colon and bowel has been stretched, and of course takes longer to fill, making bowel movements further apart (days). What my son's doctors told me was to put mineral oil in chocolate milk ( one tablespoon) and have him drink it every morning. Make sure that it is after a bowel movement and is all cleared out. The mineral oil lubricates the insides, making it impossible to back on a bowel movement. If you do this everyday, it may take up to 6 months to get the colon and bowel back to normal size.