The thermal environment is an important factor in the neonatal care of preterm infants, with effects on mortality and metabolic rate in these infants.

• It has been known for many years that low birthweight infants raised in subthermo-neutral conditions grow more slowly than those in thermo-neutral conditions, if each group receives identical feeding (120cal/kg/day).
• The infants are able to make up this difference when given a caloric supplement sufficient to match the calculated cost of the cold-induced metabolic rise. ¹ Using computer controlled incubator systems, improved caloric efficiencies for growth has been reported. ²

• There is limited scientific evidence for when to move the healthy growing preterm infant from a relatively warm incubator to a bassinet at room temperature.
• A study of healthy preterm infants moved to bassinets at different points - either a weight of 1600-1700g, or 1800-1900g, showed the rate of weight gain correlated with gross energy intake only and did not differ between the two groups. However, the rate of growth of skin folds increased dramatically after infants were moved from the incubator. This faster deposition of subcutaneous fat implies that the distribution of energy to fat, as opposed to muscle, visceral and skeletal growth, may be regulated by the thermal environment. This could represent an adaptation for better insulation against cold, however, the authors speculate that this may divert growth from other organs. ³

These factors should be taken into account when the decision is made to move an infant from an incubator to a bassinet. Consideration of appropriate clothing including head cover is important.  Can a baby increase its oral intake sufficiently, and is increased growth of fat better than growth of other vital organs?

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