Nutrition and growth in moderate to late preterm infants

Abstract

Moderate to late preterm (MLPT) infants comprise the majority of preterm infants but little is known about optimal nutritional practices and long-term outcomes for these infants. We aimed to assess growth and body composition changes from birth to four months’ corrected age, the effect of postnatal nutritional practices on body composition at four months’ corrected age, and neurodevelopmental outcomes at two years’ corrected age in MLPT infants participating in the DIAMOND trial. DIAMOND is a randomised factorial design clinical trial assessing the effect of different postnatal nutritional practices in MLPT infants on body composition at four months’ corrected age and neurodevelopmental outcomes at two years. We found that skinfold thickness measurement is not an accurate method for assessing infants’ body composition. Conditional growth analysis showed that changes in length after discharge were more related to fat free mass at four months, while changes in length before discharge were more related to fat mass at four months whereas changes in weight after discharge had a similar association with fat mass and fat free mass at four months. Girls and boys gained similar fat mass between discharge and four months, but boys gained more fat free mass than girls. Small for gestational age (SGA) infants gained more fat mass but not more fat free mass than appropriate for gestational age (AGA) infants over this period. Preliminary analysis of randomised data showed that early nutritional practices were unlikely to change body composition at four months’ corrected age, and that neurodevelopmental outcomes were in the normal range at two years’ corrected age. These findings suggest that better measures of body composition are required for New Zealand infants, but that growth in length may be a useful measure of early lean tissue growth. Patterns of growth and body composition changes are different between MLPT girls and boys and SGA and AGA infants. If the final analysis of DIAMOND trial confirms our preliminary findings, clinicians can choose nutritional practices that best suits mothers, infants, and local resources. Further follow-up will help determine the long-term outcomes of these nutritional practices in MLPT infants.