It is a normal physiological phenomenon for babies to cry after birth. When a baby is born and inhales a mouthful of fresh air, the lungs expand backward from their initial curvature, and when air is exhaled, the air in the lungs is expelled, creating stimulation as it passes through the vocal organs, hence the cry. A baby’s first cry represents the beginning of the functioning of his respiratory system, from dependence on the mother for survival, to independent survival. When the baby is still in the fetal state, it is in amniotic fluid all day long. Amniotic fluid, along with the mother’s blood and other fluids, can easily flow into the baby’s mouth during labor, and the baby has to cry loudly after birth in order to expel the dirt from its throat. In the absence of crying, the doctor will make the baby cry by patting him or her on the back. If the baby has not cried since birth, it should be promptly regulated or treated under the guidance of a doctor.