Umbilical serum insulin-like growth factor 1 (IGF-1) in newborns: effects of gestational age, postnatal age, and nutrition.

Aim: The aim of this study was to determine the relationship between nutrition, gestational age, and birth weight, and serum insulin-like growth factor 1 (IGF-1) levels in newborns.

Method: The first study group consisted of sixty newborns: thirty were fed with human breast milk and the others were fed with infant formula. Serum samples were obtained from all the newborns on days one and seven of life. Seventy-two pregnant women and their neonatal cord blood serum samples were obtained in a labor ward in the study group. All the serum samples were analyzed for IGF-1 by immunoassay.

Result: Newborns fed with human milk had higher serum IGF-1 concentrations compared to formula-fed controls (p < 0.05). Cord IGF-1 levels showed a negative correlation with birthweight (p < 0.05) and a positive correlation with gestational age (p < 0.05).

Conclusion: These findings suggest that IGF-1 levels during the neonatal period are influenced by gestational age, birth weight, and nutrition.