RESUMEN
BACKGROUND: Trace elements are an essential nutritional component for humans and inadequate tissue-concentrations may have a significant effect on fetal size. OBJECTIVE: To measure ten trace elements in blood samples from mothers and their newborns, and assess their association with anthropometric characteristics at birth. The effects of other factors on fetal growth, such as biologic characteristics of the infant and mother, were analysed. METHODS: A cross-sectional study was conducted in the Hospital general, University of Valencia, Spain. Healthy pregnant women, and their full-term infants were selected (n = 54 paired samples). Infants were grouped according to birth weight: small for gestational age (SGA n = 11), appropriate (AGA n = 30), and large (LGA n = 13). Anthropometric and biologic characteristics of the infant and mother were recorded. Levels of ten essential elements: arsenic (As), barium (Ba), cobalt (Co), copper (Cu), chrome (Cr), iron (Fe), magnesium (Mg), manganese (Mn), selenium (Se) and zinc (Zn), in maternal and cord plasma samples were determined. Samples were obtained from the umbilical cord immediately after delivery and the samples of their mothers were drawn at 2-4 h after delivery. RESULTS: The analysis identified that cord blood Cu (p = 0.017) and maternal blood Ba and Mg (p = 0.027 and p = 0.002, respectively) concentrations were significantly higher among SGA infants compared to AGA and LGA infants. A multiple linear regression analysis showed that increased umbilical cord Cu concentration (adjusted ß -146.4 g, 95% CI -255 to -37.7; p = 0.009), maternal smoking during pregnancy (adjusted ß -483.8 g, 95% CI -811.7 to -155.9; p = 0.005), shorter gestational age (adjusted ß 350.1 g, 95% CI 244.5 to 455.8; p = 0.000), and female sex (adjusted ß -374 g, 95% CI -648 to -100; p = 0.009) were significantly associated with decreased birth weight. Maternal anaemia was positively associated with birth weight (adjusted ß 362 g, 95% CI 20.8 to 703.1; p = 0.038). No significant associations were found between maternal trace elements and birth weight in multivariate analysis. CONCLUSIONS: We did not observe significant associations of cord blood trace elements other than Cu and maternal trace elements with birth weight in the multivariate analyses.