Is her stool soft? Does she get the urge to have a bowel movement and cannot hold it? Is it related to diet? Does she have a weak rectal sphincter and is unable to hold the stool in? If her rectal sphincter is weak, doing pelvic muscle exercises may help. You need to look at all of these things. If you have a specific event, a medication like Imodium will slow up the bowel and she may be able to go several hours without a problem but speak with your doctor about this.