Effects of aggressive parenteral nutrition on growth and clinical outcome in preterm infants.

Background: The goal of nutrition in the preterm infant is to achieve postnatal growth approximating normal fetal growth. During the early postnatal period, protein intake must be sufficient to achieve normal postnatal growth in extremely low-birthweight infants. The aim of this study was to test the hypothesis that giving higher amounts of amino acids and lipids to infants born at <34 gestational weeks (GW) may improve growth at the 40th week of gestation and have a positive preventive effect on development of retinopathy of prematurity (ROP).

Methods: Fifty-three neonates born at <34 GW and hospitalized in the neonatal intensive care unit (NICU) were included in this prospective study. They were randomly divided into two groups. Group 1 received aggressive parenteral nutrition (PN) (amino acids 3 g/kg per day and lipids 2 g/kg per day on first day of life). Group 2 received conventional PN (amino acids 1.5 g/kg per day and lipids 1 g/kg per day on first day of life). The anthropometric measurements, clinical outcomes and serum levels of insulin-like growth factor-I (IGF-I), IGF binding protein (IGFBP) and thyroid hormones were compared between groups.

Results: At 40 weeks of gestation, height, head circumference and serum IGF-I and IGFBP3 were statistically higher in the group receiving aggressive PN. Thyroid hormones were not affected by aggressive PN. The lower levels of IGF-I and IGFBP3 in the group receiving conventional PN were negatively correlated with development of ROP.

Conclusion: Aggressive PN seems to positively affect neonates' anthropometric measurements at the 40th gestational week and the development of ROP. These effects may be related to high levels of IGF-I and IGFBP3.