Neonatal Nurse Practitioner Practice Exam

What primarily contributes to a preterm neonate's decreased ability to maintain normal body temperature?

1. Decreased thermal receptors in the skin

2. Large surface area relative to body mass

3. Limited subcutaneous tissue and brown fat

4. Higher metabolic rate

The correct answer is: Limited subcutaneous tissue and brown fat

The primary reason for a preterm neonate's decreased ability to maintain normal body temperature is their limited subcutaneous tissue and brown fat. Premature infants are born before they have developed adequate stores of these crucial components for thermoregulation. Subcutaneous fat serves as an insulator that helps retain heat, while brown fat is metabolically active and generates heat through a process called non-shivering thermogenesis. The lack of sufficient brown fat in preterm infants makes it challenging for them to produce enough heat to maintain their body temperature in the external environment. While factors such as a large surface area relative to body mass also play a role in heat loss, the fundamental issue revolves around the insufficient protective fat layers and the inability to generate heat effectively, which places preterm neonates at significant risk for hypothermia.