[Extrauterine growth restriction among neonates with a birthweight less than 1,500grams].

INTRODUCTION: Growth restriction in preterm infants has been related to a poor neurodevelopment outcome.

OBJECTIVES: To define the incidence of postnatal growth restriction in premature babies ≤1,500 grams and to detect related clinical or biochemical markers.

METHODS: Retrospective longitudinal observational study. Multivariate linear regression models were used to determine variables that can predict the change in weight z-score during admission.

RESULTS: The study included 130 patients with a mean birthweight of 1,161±251grams and a gestational age of 29.9±2.5 weeks. At hospital discharge, 59.2% had a weight below P10.During admission, the z-scores of weight and length decreased by -0.85±0.79 and -1.09±0.65, respectively.The largest decrease in z-score occurred during NICU admission, with a weight gain rate of 6.6±8.8g/Kg/day, after which growth acceleration took place (16.7±3.8g/Kg/day), but was insufficient to catch-up.Higher levels of urea were negatively correlated with the change in the z-score of weight (P<.001), and a weight <P10 at birth positively correlated (P=.013).

CONCLUSIONS: More than half of newborns ≤1,500 grams have a weight at discharge of <P10. This growth restriction occurs during NICU admission, and affects low birth weight infants less frequently.Urea levels correlate negatively with weight gain, which requires further study of the relationship between growth and the protein compartment.