From the Guidelines
Infants are at high risk for decreased body temperature due to greater surface area to body weight, low body fat, and lack of shivering response. The greater surface area to body weight ratio means infants lose heat more rapidly than adults, as heat loss occurs primarily through the skin surface 1. Infants also have low body fat, which serves as insulation in adults, making them more susceptible to heat loss. Additionally, infants lack a developed shivering response, which is an important mechanism for heat generation in older children and adults. When the body temperature drops, shivering generates heat through muscle contractions, but this thermoregulatory mechanism is not fully functional in newborns. Instead, infants rely primarily on non-shivering thermogenesis through brown adipose tissue, which is less efficient.
Some key factors that contribute to heat loss in infants include:
- Greater surface area to body weight ratio
- Low body fat
- Lack of shivering response These physiological differences make temperature regulation challenging for infants and explain why they require extra care to maintain normal body temperature, especially in cold environments 1. It is essential to implement strategies to minimize heat loss, such as occlusive wrapping, exothermic warming mattress, warmed humidified resuscitation gases, polyethylene caps, and increasing delivery room temperature, to prevent hypothermia and its associated risks 1.
From the Research
Reasons for Decreased Body Temperature in Infants
The following are reasons why infants are at high risk for decreased body temperature:
- Greater surface area to body weight: Infants have a large surface-to-volume ratio, which is a key thermal factor that contributes to heat loss 2.
- Low body fat: Infants, especially those with low birth weight, have less body fat to insulate themselves, making them more susceptible to hypothermia 3, 4.
- Lack of shivering response: Unlike adults, infants may not be able to shiver effectively to generate heat, making them more vulnerable to hypothermia 5.
Other Factors
Other factors that may contribute to decreased body temperature in infants include:
- Environmental factors, such as low ambient temperature 3, 6.
- Physiological factors, such as respiratory morbidity and thermal instability 4.
- Clinical factors, such as being born at night, being nursed in a cot, and having a low birth weight 3.
Note: Increased shivering response and high body fat are not supported by the provided evidence as reasons for decreased body temperature in infants. Less surface area to body weight is also not a correct reason, as infants actually have a greater surface area to body weight ratio.