What predisposes newborns to heat loss?

• A. Small surface area relative to body weight
• B. Increased body fat
• C. Limited capacity for thermoregulation
• D. Large surface area relative to body weight

Answer: (D)

Newborns are particularly susceptible to heat loss due to their relatively large surface area compared to their body weight. This larger surface area means that they have more skin exposed for the loss of heat to their environment. The principle of heat transfer indicates that the greater the surface area, the more heat can be lost through radiation, conduction, convection, and evaporation.

In newborns, the skin is also thinner and less effective as a barrier compared to older children and adults, making it easier for heat to exit the body. Additionally, the subcutaneous fat layer in newborns, while present, is not as developed or as effective insulators as in older individuals, which further contributes to their vulnerability to hypothermia.

The limited capacity for thermoregulation in newborns means they are unable to effectively control their body temperature through mechanisms such as shivering or adjusting blood flow to the skin, making the large surface area to weight ratio a key factor in their predisposition to heat loss.