Adaptation To Extrauterine Life - Temperature Regulation

Temperature Regulation

Newborns come from a warm environment to the cold and fluctuating temperatures of this world. They are naked, wet, and have a large surface area to mass ratio, with variable amounts of insulation, limited metabolic reserves, and a decreased ability to shiver. Physiologic mechanisms for preserving core temperature include vasoconstriction (decrease blood flow to the skin), maintaining the fetal position (decrease the surface area exposed to the environment), jittery large muscle activity (generate muscular heat), and "non-shivering thermogenesis". The latter occurs in "brown fat" which is specialized adipose tissue with a high concentration of mitochondria designed to rapidly oxidize fatty acids in order to generate metabolic heat. The newborn capacity to maintain these mechanisms is limited, especially in premature infants. As such, it is not surprising that some newborns may have problems regulating their temperature. As early as the 1880s, infant incubators were used to help newborns maintain warmth, with humidified incubators being used as early as the 1930s.

Basic techniques for keeping newborns warm include keeping them dry, wrapping them in blankets, giving them hats and clothing, or increasing the ambient temperature. More advanced techniques include incubators (at 36.5°C), humidity, heat shields, thermal blankets, double-walled incubators, and radiant warmers while the use of skin-to-skin "kangaroo mother care" interventions for low birth-weight infants have started to spread world-wide after its use as a solution in developing countries.