The newborn spitting up phenomenon is more common for the following reasons: 1, the newborn baby’s digestive system is not well developed, the stomach is horizontal, the capacity of the stomach is small, the cardia sphincter is relaxed, the intake of milk a little more will appear spitting up. 2, improper feeding methods, newborns eat milk, because crying leads to eating milk often inhale air, milk is easy to flow into the mouth caused by spitting up. Incorrect posture of feeding, oversized rubber nipple orifice, too fast or too much milk, lying down immediately after feeding can lead to vomiting, it is recommended not to feed too much milk, to eat less and more, to raise the baby’s head when feeding, to put it down again after a few minutes, or to gently pat the baby’s back to make it burp. 3, vomiting caused by disease, if the baby vomits within 24 hours of birth If your baby spits up milk within 24 hours of birth, or spits up more milk, or even spits up milk in the form of jets, you should go to the hospital promptly for examination to clarify the cause.