At birth, how is a 29-week gestation infant most likely to lose body heat?

A 29-week gestation infant, being preterm, is at a greater risk for heat loss due to several factors related to their size, skin condition, and environmental exposure. Evaporation is a significant mode of heat loss for any newborn, particularly for preterm infants, as they are often born with wet skin after delivery. The process of evaporation occurs when moisture on the skin surface converts to vapor, which leads to a significant drop in body temperature.

In addition to evaporation, convection also plays a role in heat loss. Convection refers to the transfer of heat through air or fluid moving around the baby. For instance, if the infant is in a breezy environment or if cooler air is moving across their skin, heat can be lost to the surrounding air.

Understanding the mechanisms of heat loss in newborns is crucial for ensuring that preterm infants, who lack sufficient insulating subcutaneous fat and often have a large body surface area relative to their weight, are adequately warmed during and after birth. This is essential for their survival and helps prevent hypothermia, which can lead to further complications in vulnerable infants.