The normal body surface temperature of newborns is 36.0 to 36.5°C, and the normal core (rectal) temperature is 36.5 to 37.5°C. Neonatal thermoregulatory center function is not yet perfect, the subcutaneous fat is thin, the body surface area is relatively large, the skin epidermal keratinization layer is poor, easy to dissipate heat. Neonates have no chilling response when cold, but rely on brown fat chemical heat production. Premature infants have less brown fat and poor heat production capacity, so they are more likely to suffer from hypothermia and even sclerosis when cold. High ambient temperature, low water intake and insufficient heat dissipation can increase body temperature and lead to dehydration fever. Be careful not to cover the child too much, many parents love their children, the warmth measures for children often more than ever, the child wrapped up tightly. In fact, this has fewer advantages and more disadvantages, when the temperature inside the quilt exceeds 34 ℃, the newborn will occur hyperthermia, a lot of sweating, resulting in a large loss of extracellular fluid, resulting in dehydration, metabolic acidosis, cerebral hypoxia and cerebral edema and a series of adverse consequences, medically known as infantile smothering syndrome. How to keep warm: In principle, it is appropriate for the child to have a normal face, warm extremities and no sweating. If the newborn behaves abnormally, has sweaty face and body temperature above 37.5℃, it indicates excessive warmth and should reduce some clothes and blankets. If the child’s hands and feet are cold and the body temperature is less than 36℃, it means that the warmth is not enough and it is necessary to add more clothes and increase the room temperature.