Why are premature infants at a higher risk of hypothermia?

Premature infants are at a higher risk of hypothermia primarily due to their larger surface area to body mass ratio. This physiological characteristic means that they have more skin relative to their weight, which results in a higher heat loss through radiation, convection, and evaporation. As their body is not able to generate sufficient heat to compensate for this loss, they are particularly vulnerable to becoming hypothermic.

In comparison, factors like insulating fat, birth weight, and muscle tone play less significant roles in their thermal regulation. Premature infants may actually have less insulating fat than full-term infants, which further increases their risk of hypothermia. Additionally, lower birth weights are common in premature infants, and stronger muscle tone does not directly contribute to temperature regulation. Thus, the unique surface area to mass ratio is the key reason for their increased susceptibility to hypothermia.