Up to 40% of all babies have non-specific digestion problems during the first months, such as gas, colic or constipation. Until their fourth month, many babies have stomach cramps. This is known as colic. Colic symptoms are often accompanied by persistent crying. Many parents feel powerless and tend to feel stressed. Experts are still not sure what causes colic. The immature digestive tract is believed to cause problems for babies, causing gas and cramping.