Newborns spitting up in their sleep may be caused by physiological factors, infections, gastrointestinal lesions and other factors. 1. Physiological factors: due to the newborn’s stomach capacity is small, and horizontal position, in the bedtime to eat more milk, and sleep posture is bad, there will be physiological spit up, after adjusting the child’s sleep posture, can be restored to normal. 2. Infection: for example, pneumonia or meningitis, due to the presence of infection, will lead to newborns spitting up in their sleep, may also be accompanied by fever, fatigue, crying and other abnormal manifestations. 3. Gastrointestinal lesions: For example, a cold abdomen after feeding may lead to indigestion, which will lead to spitting up in bed, which may be accompanied by crying and bloating. Newborns spit up in their sleep, and exclude physiological factors, there are other abnormal manifestations, parents are advised to take their children to the doctor for examination and treatment in a timely manner to avoid delays in the condition.