All infants are at risk for cold stress particularly within the first 12 hours of life. There are four mechanisms for heat loss, conduction, convection, radiation and evaporation. Conduction involves heat transfer from one object to another by actual contact. Examples of conduction include a cold mattress or scale in which if contact were to occur would be causative in heat loss for the infant. Conversely, if a warmed mattress or scale would come into contact with an infant it would cause heat gain.
Convection involves heat loss or gain by air motion.
An example of convection related heat loss would be a cool breeze. An example of a convection related heat gain would be the warm air currents in a heated isolette. An example of radiant heat loss would be the micropreemie infant in a single walled isolette next to a cold window. The infant would become cold regardless of the fact that he is in a heated isolette. Conversely, in the same situation but by a warm window in the sun, the infant would become to warm due to radiant heat gain.