Baby persistent fever more than 39 ℃, good mental state, no other symptoms generally will not be dangerous, but high fever is easy to cause febrile convulsions convulsions, and fever causes, it is recommended that timely medical treatment. In general, the baby fever more than 39 degrees, good mental state, and will not be dangerous, but 39 degrees belongs to the high fever, each baby’s nervous system development is not perfect, easy to cause febrile convulsions (due to the high fever caused by convulsions convulsions), which may result in biting the tongue, accidental inhalation of vomitus leading to asphyxia, etc., convulsions serious unrelieved may cause ischemia of the brain cells hypoxia and so on, to the baby caused irreversible neurological The baby’s nervous system will be irreversibly damaged. In addition, fever is the most common symptom of all diseases, the cause of which is unknown, and needs to be treated promptly by a doctor for the cause of the disease.