[Trace elements and growth factors in the perinatal period]

The objective of this study was to measure serum IGF-I, IGFBP-3, copper and zinc levels and to analyze their relationship to perinatal growth. Serum IGF-I (RIA after acid-ethanol extraction), IGFBP-3 (RIA), copper and zinc (atomic absorption spectrophotometry) levels were measured in cord blood (n = 78) and in newborn children 1 (n = 110) and 3 (n = 42) weeks after birth. Anthropometric variables were measured and the weekly average intake of energy and nutrients were calculated. We found that IGF-I and zinc levels during the 1st week of postnatal life were lower in fullterm LGA and AGA and in preterm (PT) AGA infants than in cord blood. The highest IGF-I levels were obtained in LGE fullterm infants (37.9 +/- 29.5 ng/mL) and the lowest in SGA preterm infants (9.3 +/- 10.3 ng/mL). Serum zinc levels in preterm neonates continued decreasing at the 3rd week after birth. However, IGF-I and IGFBP-3 levels increased significantly (IGF-I: 13.2 +/- 15.5 vs 34.5 +/- 27.3 ng/mL, p < 0.01; IGFBP-3: 364.3 +/- 185.1 vs 634.1 +/- 306.9 ng/mL, p < 0.01). Serum copper levels in the control group increased in relationship to the levels found at the 1st week of life, while this increase neither happened in fullterm SGA infants nor in preterm infants. A positive relationship was found between IGF-I and IGFBP-3. Both were directly connected to energy and protein intake. We conclude that intrauterine over-nutrition is related to higher IGF-I levels, whereas prematurity and intrauterine growth retardation are associated with lower zinc, IGF-I and IGFBP-3 levels and with a lack of increase in copper serum levels.