To survive normally, the lungs must breathe normally, and when the baby is in the womb, the alveoli are closed and do not need to breathe, while crying at birth can breathe air into the lungs to open the alveoli completely, so that the lungs can breathe normally. If there is no crying at birth, some of the alveoli will not be fully opened, or amniotic fluid into the alveoli, so that the baby can not breathe normally and well, resulting in breathing difficulties, lack of oxygen and other performance, serious cases can affect the development of brain cells, intellectual development or other effects, and even life-threatening.