The reasons why newborns stretch hard and especially frequent are generally intestinal flatulence and excessive growth, as follows: 1. Intestinal flatulence: newborns are just born, the function of the digestive system is not yet well developed, and the digestive function is relatively weak. If the amount of milk eaten is too large, the process of eating milk too quickly, too fast, will swallow to stomach some air, or the abdomen is cold, etc., will appear intestinal flatulence. The baby frequently stretches and strains, probably to eliminate the gas in the intestines, thus relieving bloating. 2, growing too fast: newborns in the first three months of life, both weight and length, growth rate is usually faster, bones, tendons, muscles, skin are growing rapidly. Rapid growth may not be adapted by the child, which leads to physical discomfort, coupled with a short sleep cycle, deep and light sleep often switch, there will be frequent stretching and straining to relieve the above discomfort.