Newborns sleeping with their mouths open can be physiological phenomena or pathological conditions, whether it is normal or not needs to be analyzed. 1. Physiological phenomenon: If the baby’s mouth is open during sleep, and the baby has no obvious abnormal symptoms, such as fever, cough and other symptoms, it is often considered to be a normal physiological phenomenon, without special intervention. Or the ambient temperature is low or less wrapped, newborns are prone to nasal congestion, this time there can be open-mouth breathing, but can not be considered abnormal, is a normal physiological response, but need to pay attention to adjust the indoor temperature and wrapping, and so on. 2. Pathological conditions: such as neonatal pneumonia, the baby can appear fever, moaning, spitting obvious phenomena, such as sleeping with the mouth open phenomenon, which is the disease state, is not normal, the need for timely intervention and treatment, to avoid delays in treatment aggravation of the condition. About the newborn sleep mouth open need to be combined with the baby with or without other special circumstances, it is recommended that when necessary to consult a specialist physician judgment assessment.