Spitting up after feeding a newborn baby may be related to physiological factors, or it may be caused by indigestion, gastrointestinal diseases and other reasons. 1. Physiological factors: Since the stomach of a newborn presents a horizontal position, if the child eats milk too fast, swallows more gas, or lies down immediately after eating milk without burping, spitting up may occur. 2. Indigestion: the development of the gastrointestinal system of newborns is still immature, if parents do not feed properly, give the child too much milk at one time, or feeding too often, may lead to indigestion, resulting in gastrointestinal dysfunction, there may be the phenomenon of spitting up after feeding, may also be accompanied by abdominal distension, abdominal pain and other manifestations. 3. Gastrointestinal diseases: such as pyloric hypertrophy, intussusception, congenital megacolon and other diseases, may cause vomiting after eating milk, may also be accompanied by abnormal bowel movements, frequent crying and other manifestations. Newborns spit up after eating milk, may also be related to other factors, if the symptoms of frequent recurrence, or the presence of other obvious discomfort, you should seek medical attention as soon as possible, after diagnosis of the causative factors to give targeted treatment.