Intestinal Distress
Intestinal pain could be the cause of your baby's unwillingness to sleep. If your baby is crying and having trouble sleeping, it could be a tummy ache that is causing her problems.
Gas
If the baby is not crying because she is hungry, particularly if you just fed her, she may have a gas bubble and need to be burped. Babies, like anyone else, can also get plain old tummy aches. A tummy ache may result from a simple gas bubble (the most common cause) or something more complex. If your baby is one who needs burping, maybe you didn't get all the gas out when you burped her after dinner. If your baby is one who normally doesn't need burping, maybe just this once she has a stubborn gas bubble that she needs a little help dislodging. To try to dispel a gas bubble, hold her upright and rub her back in a circular motion.
Alert!
Some babies burp naturally. Such a baby usually doesn't need to be burped by your rubbing or gently patting his back. But occasionally one of these babies gets a gas bubble in his tummy that he cannot dislodge on his own. Even if your baby is a “self-burper,” it can't hurt to try to burp him in case that's the cause of his crying.
Lactose Intolerance
Another cause of intestinal problems is lactose intolerance. This is an inability in the baby's system to digest lactose, or milk sugar. The baby who is lactose intolerant typically is fussy all the time, not only at night. (A less common possibility, but one you might also consider, is cow's milk protein allergy, in which case the culprit is not milk sugar but milk protein.) You should be particularly alert to the possibility of lactose intolerance if your baby suffers from frequent loose and/or foul-smelling bowel movements. If you suspect that your baby has lactose intolerance or cow's milk protein allergy, talk to your pediatrician. Switching your child to a soy-based formula or an elemental formula may alleviate the problem if an intolerance to cow's milk or to breast milk is the cause. If you are breastfeeding, first try eliminating dairy products from your own diet for a week or two and see if that doesn't make a big difference. Once there are no milk proteins to pass from your system into your breast milk as the result of your diet, your child's problem may well be alleviated.
If you've begun feeding your baby strained foods, she might also have an allergy to one of the foods you're feeding her. Even if she's not actually allergic, her stomach might simply be having a bit of trouble handling some food you've introduced. She might also be eating too much. An overfull tummy could make her feel uncomfortable and/or gassy.
