Add up all the time your baby spends snoozing. If she's sleeping for 13 or 14 hours a day, that's normal for a child her age and there's no need to worry -- she's probably just redistributed her sleep into a new pattern. But if your daughter has increased her total amount of sleep by more than an hour a day or is logging 15 or more hours, have your pediatrician check for an underlying cause. She could have an iron deficiency, which is common in babies who are exclusively breastfed or who drink formula that's not iron-fortified. Low thyroid hormone could also be causing the problem. If a thorough checkup reassures you and your pediatrician that everything's fine, it may simply be that your baby has recently become much more active; crawling and learning how to walk can definitely tire a baby out.