Maternal zinc and cord blood zinc, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels in small-for-gestational-age newborns

PURPOSE: To determine the relationship between maternal serum zinc (Zn) levels and birth weight of the offspring and their correlation with cord blood Zn, insulin-like growth factor (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) levels. METHOD: 22 term small-for-gestational-age (SGA) and 34 term appropriate-for-gestational-age (AGA) infants and their mothers were included. Maternal and cord blood Zn levels and cord blood IGF-1 and IGFBP-3 levels were measured. RESULTS: Eighteen percent of mothers had Zn deficiency (< 75 mcg/dl). No significant difference between IGF-1 and IGFBP-3 levels and birth weight of infants of the mothers with and without Zn deficiency was found. Maternal and neonatal Zn levels correlated (r = 0.38, p < 0.01). Mean IGF-1 and IGFBP-3 levels were significantly lower in the SGA group compared to the AGA group (42.3 +/- 16.8 ng/ml, 1.2 +/- 0.2 mcg/ml, and 62.4 +/- 22.7 ng/ml, 1.5 +/- 0.4 mcg/ml, p < 0.001). A correlation was found between birth weight, IGF-1 and IGFBP-3 levels, and weight gain of the mother during pregnancy (p < 0.01). CONCLUSIONS: Zn deficiency was not observed to be a risk factor for low birth weight. The significant difference between the SGA and AGA babies' IGF-1 and IGFBP-3 levels emphasizes function of the IGF system in intrauterine growth.