Growth and fat-free mass gain in preterm infants after discharge: a randomized controlled trial.

Objective: To investigate whether the consumption of a nutrient-enriched formula after hospital discharge determines different growth and weight gain composition in preterm infants according to intra- and extrauterine growth pattern.

Methods: Two hundred seven preterm infants were randomized at term-corrected age to receive treatment A (term formula) or B (nutrient-enriched formula) up to 6 months of corrected age, using 2 computer-generated randomization lists, 1 for adequate for gestational age (AGA) and 1 for small for gestational age (SGA) infants. Infants were weaned according to our clinical practice after 6 months' corrected age. Anthropometric parameters and body composition by an air displacement plethysmography system were assessed at term and 1, 3, and 6 months' corrected age. Anthropometric parameters were also assessed at 12 months.

Results: Protein intakes were higher in infants receiving treatment B than in infants receiving treatment A at each study point. There were no differences between the feeding groups in weight and length SD scores in either the AGA and SGA group through the study. The mean head circumference values were higher in AGA infants receiving treatment B than in AGA infants receiving treatment A at 6 and 12 months, whereas at 6 months, the percentage of fat mass was lower. No difference in body composition was detected among SGA infants through the study.

Conclusions: This randomized controlled trial demonstrates the beneficial effect of the consumption of a nutrient-enriched formula after hospital discharge by AGA infants both in terms of head circumference growth and fat-free mass gain.