Relation of cord serum levels of growth hormone, insulin-like growth factors, insulin-like growth factor binding proteins, leptin, and interleukin-6 with birth weight, birth length, and head circumference in term and preterm neonates

OBJECTIVES: Fetal growth process is governed by multiple factors. We investigated the relation of insulin-like growth factors (IGFs), IGF binding proteins (IGFBPs), leptin, and interleukin-6 (IL-6) with intrauterine growth in preterm and term neonates. METHODS: Thirty-eight preterm and 43 term neonates were recruited. Anthropometric measures were recorded and umbilical cord blood samples were collected at birth. RESULTS: Birth weight (BW), birth length (BL), ponderal index, head circumference (HC), and cord serum levels of albumin, prealbumin, retinol-binding protein (RBP), total and free IGF-I, IGF-II, IGFBP-3, acid-labile subunit (ALS), and leptin were significantly lower, whereas levels of IGFBP-1, IGFBP-2, and IL-6 were significantly higher in preterm than in term neonates (P < 0.05). Total and free IGF-I, ALS, and leptin had significantly positive correlations, whereas IGFBP-2 had a significantly negative correlation, with BW and BL in preterm plus term neonates. Forward stepwise multivariate regression analysis showed that gestational age (GA), IGFBP-2, leptin, and free IGF-I are significant predictors of BW; GA, IGFBP-2, ALS, transferrin, and leptin are significant predictors of BL; and GA and free IGF-I are significant predictors of HC in preterm and term neonates. CONCLUSIONS: Our results suggest that IGF-I, IGF-II, IGFBP-2, ALS, and leptin play important roles in intrauterine growth.