Gestational age-specific reference intervals for blood copper, zinc, calcium, magnesium, iron, lead, and cadmium during normal pregnancy

Objectives: The aim of this study was to investigate the blood copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), iron (Fe), lead (Pb), and cadmium (Cd) concentrations in women of <= 12 (group I), 13-20 (group II), 21-27 (group III), 28-35 (group IV), and 36-42 (group V) weeks of gestation and compare them with those in nonpregnant women. Design and methods: The cross-sectional study was performed in 2380 pregnant women [group I (n = 550); group II (n = 552); group III (n = 600); group IV (n = 553); and group V (n = 125)] and 552 nonpregnant women as controls. Blood seven element concentrations, including Cu, Zn, Ca, Mg, Fe, Pd, and Cd, were determined by atomic absorption spectrometry (AAS). Results: Compared with the nonpregnant women group, the concentrations of Cu, Zn, Ca, Mg, Fe, Pb, and Cd at <= 12, 13-20, 21-27, 28-35, and 36-42 weeks of gestation, on the whole, were significantly different. Blood Cu, Mg, Ca, Fe, Pb, and Cd concentrations were correlated with weeks of gestation (P < 0.05). The gestational age-specific reference intervals were established for Cu, Zn, Ca, Mg, Fe, Pd, and Cd. Conclusions: The established reference intervals for Cu, Zn, Ca, Mg, and Fe can provide important guidance for the reasonable supplementation of essential elements in pregnancy. And the reference intervals for Pd and Cd can play an important part in the surveillance and diagnosis of environmental overexposure. (c) 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.