Background: Earlier studies indicate that some term infants born by elective cesarean section start to sweat in a warm environment while others do not, and that sweating is inhibited by feeding cold glucose. The aim of this study was to investigate whether vaginally born infants react the same way when fed cold water.

Subjects: Fourteen vaginally born term infants on the first day after birth.

Interventions: The infants were nursed at a temperature of 36.6°C until rectal temperature (TRECT) reached 37.5 °C or sweating occurred. The infants were then fed cold water. Evaporation rate (ER; g/m2h), skin blood flow (Qs), and body and skin temperatures were measured before and after administering cold water.

Results: Sweating occurred in 9 infants at or below a TRECT of 37.5 °C. In infants who started to sweat, ER increased from 5.6±2.8 to 15.7±10.6 (SD) (p<0.05). Ten minutes after feeding cold water, ER had decreased to the level obtained before sweating. Qs increased by 42% during sweating and decreased by 22% after the feeding (p<0.01). In infants who did not sweat, no increase in ER was noted and the changes in Qs were less marked.

Conclusion: Some, but not all, vaginally born infants start to sweat in a warm environment. Sweating and concomitant changes in Qs are inhibited by feeding cold water. This may indicate an individual difference in the post-natal adaptation of the central temperature set-point.