A neonate in the delivery room is at high risk for hypothermia. Which anatomical and physiological characteristic MOST predisposes the newborn to rapid heat loss compared to adults?

• A Inability to shiver
• B Higher surface-area-to-body-mass ratio ✓
• C Absent brown adipose tissue
• D Overactive sweat glands

Explanation

Neonates have a substantially higher surface-area-to-body-mass ratio than adults, which increases heat loss by radiation, convection, and evaporation. This is the single greatest predisposing factor. Newborns do have brown adipose tissue for non-shivering thermogenesis and cannot shiver effectively, but the surface area ratio is the dominant contributor to heat loss. Neonatal sweat glands are immature, not overactive.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.