BREAST-FEEDING AND GROWTH-FACTORS IN PRETERM NEWBORN-INFANTS

Background: We analyzed the role that nutrition and the insulin-like g rowth factors IGF-I and IGFBP-3 play on neonatal growth. Methods: Full -term and preterm infants with 1 and 3 weeks of postnatal life (n = 54 and n = 33, respectively) were studied. Anthropmetric variables, dail y intake of energy and nutrients, and serum levels of IGF-I and IGFBP- 3 were measured. Results: At the first week after birth, preterm infan ts had lower IGF-I levels than did those in the control group. At the third week of postnatal life, serum IGF-I and IGFBP-3 levels showed a significant increase. Preterm infants born before 33 gestational weeks showed lower IGF-I (p < 0.02) and IGFBP-3 (p < 0.02) levels than thos e born between 33 and 37 gestational weeks. Preterm infants fed with h uman milk supplemented with a formula showed higher serum IGF-I levels than those fed exclusively with a mirk formula (mean +/- SEM 48.2 +/- 9.5 mu g/L vs. 25.4 +/- 4.4 mu g/L, p < 0.05). IGF-I and IGFBP-3 were correlated between themselves and with energy and protein intake. Mul tiple regression analysis confirmed that energy intake and serum IGEBP -3 levels were the most predictable variables with regard to IGF-I lev els at neonatal period. Conclusions: These feedings suggest that IGF-I levels during the neonatal periods are influenced by the maturity sta ge of the newborn, energy intake, and the type of lactation. (C) 1997 Lippincott-Raven Publishers.