Transepidermal water loss in newborn infants. VI. Heat exchange with the environment in relation to gestational age.

The amount of water evaporated from the skin of newborn infants and the temperatures of the skin, of the ambient air, and of the surfaces facing the infants were measured and used as a basis for calculation of the evaporative, radiative and convective heat exchange between the infant and the environment. The infants were of varying gestational ages, from 25 to 39 completed weeks of gestation. Evaporative heat exchange was high in the most preterm infants when nursed at a low ambient humidity, while the high ambient humidity needed to maintain these infants at a stable body temperature led to a low loss of heat through radiation and convection or even a heat gain. In the more mature infants evaporative heat exchange was lower, while radiative and convective heat exchange was higher.