A term neonate is delivered and placed under a radiant warmer. The primary mechanism by which a neonate generates heat in the immediate postnatal period is:

• A Non-shivering thermogenesis in brown adipose tissue ✓
• B Shivering thermogenesis in skeletal muscle
• C Metabolism of white adipose tissue triglycerides
• D Peripheral vasoconstriction reducing heat loss

Explanation

Neonates rely on non-shivering thermogenesis in brown adipose tissue, which is rich in mitochondria and uncoupling protein 1 (thermogenin). Shivering thermogenesis is minimal or absent in neonates. White fat stores energy but does not generate heat directly. Peripheral vasoconstriction reduces heat loss but does not generate heat; it is a conservation mechanism, not a production mechanism.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.