Maturation of thermal capabilities in preterm infants.

Very low-birth-weight infants (VLBW) may initially require environmental temperatures higher than skin temperature. We examined the correlation between gestational age, birth weight, and the time to reach skin-air temperature equilibration (TTE) in VLBW infants. We also examined the effect of antenatal steroids on TTE in infants with birth weight < 1000 g. There is a significant exponential correlation between TTE and birth weight or gestational age (p < 0.05). There was no significant change in TTE in infants who were treated antenatally with steroids, as compared with infants who were not treated. Multiple regression analysis with TTE as the dependent variable and birth weight or gestational age, race, betamethasone treatment, and gender as the independent variables showed a significant correlation between gestational age and TTE (p = 0.04). We conclude that thermal capabilities are exponentially correlated with gestational age or birth weight.