Environment and Growth in Preterm Infants
|Reviewed by Dr Claire West
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.
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?
a1. BioI Neonate 14 : 324; 1969.
al. Pediatrics 57 : 494; 1976.
et a1. Pediatrics 68 : 82; 1981