The sudden crying of a newborn baby may be related to physiological factors, or it may be due to pediatric colic, acute upper respiratory tract infection and other causes. 1. Physiological factors: If the newborn’s stomach is hungry, urinating, defecating, or the temperature of the environment he is in is too hot or too cold, it may make the child feel uncomfortable and may show sudden crying. 2. Pediatric colic: When a newborn has colic, it may show sudden crying. Pediatric colic is a functional intestinal spasm, which can be manifested as paroxysmal abdominal pain, due to gastrointestinal discomfort, there will be sudden crying and crying, and may be accompanied by facial redness, knee bending and other manifestations. 3. Acute upper respiratory tract infection: When a newborn is infected by a virus, which induces acute upper respiratory tract infection, it can lead to cough, runny nose, fever and other symptoms, and due to physical discomfort, it may show sudden crying and crying. Newborns suddenly cry more than, parents should promptly help find the cause, if necessary, should be timely to take the newborn to the regular hospital, a clear diagnosis of the cause, by the doctor’s guidance for treatment and conditioning.