Project Summary/Abstract
Prevalence of oral feeding difficulty in infants admitted to a neonatal intensive care unit (NICU) is
increasing. This not only leads to prolonged NICU stay, but an escalation of healthcare costs as well. A
major contributor is the increase in large for gestational age (LGA) infant birth rate because of rising
maternal obesity and diabetes during pregnancy. LGA infants are considered poor oral feeders. Significant
knowledge gaps exist in understanding the complex mechanisms implicated in LGA infants with oral
feeding difficulty. LGA infants are exposed to excess energy in utero and body composition studies have
shown that they have higher fat mass (FM) and lower fat-free mass (FFM) proportion. Oral feeding ability
can be influenced by hunger and satiety, which may have a feedback mechanism with the state of the
body's energy stores (FM as proxy) and resting metabolic rate (RMR, FFM as proxy), and these effects
may be mediated through the appetite-regulating hormone (ARH) levels. Our preliminary data suggest that
infants with a higher FM and lower FFM proportion (disproportionate body composition) took longer to
reach independent oral feeds, required longer hospitalization, and required higher g-tube placement. FFM
is better associated with oral (energy) intake than FM, suggesting that FFM is major determinant of energy
intake and appetite in infants. The standard NICU feeding strategy is focused on promoting weight gain
irrespective of birth weight or body composition, which is inappropriate in LGA infants as LGA infants who
demonstrated ‘catch-down’ growth in early infancy had better long-term outcomes. These infants had a
greater proportion of FM loss compared to FFM during the catch-down period. LGA infants with oral
feeding difficulty in the NICU are dependent on tube-feeding and the feeding intake is regulated by the care
team rather than being infant-driven. The lower FFM% in these infants may reduce their ability to meet the
standard oral intake volumes indexed to total mass (150 ml/kg/day). The continued provision of excess
calories above the metabolic needs from tube-feeding may increase their body adiposity, prevent natural
catch-down growth, and exacerbate their oral feeding difficulty. The proposed research will evaluate the
interrelationship between body composition, oral feeding ability, and ARH levels in LGA infants. Further, we
will evaluate the effects of a short-term FFM-indexed feeding (target feeding volume indexed to FFM)
versus the standard approach to feeding (target feeding volume indexed to total mass) on oral feeding
outcomes, catch-down weight, and body composition in LGA infants with oral feeding difficulty. Knowledge
gained from this proposal will provide a rationale for future studies designed to evaluate precision
nutritional therapies for LGA infants. This may ultimately shorten the length of hospital stay and enhance
the quality of life for these infants.
