title: Gestational age-specific reference intervals for blood copper, zinc, calcium, magnesium, iron, lead, and cadmium during normal pregnancy.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China. diyudeshouhuzhe@126.com
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Enwu
authors.initials: E
authors.lastname: Yuan
authors.forename: Junjie
authors.initials: J
authors.lastname: Liu
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Lou
authors.forename: Liting
authors.initials: L
authors.lastname: Jia
authors.forename: Xiaofu
authors.initials: X
authors.lastname: Li
authors.forename: Linlin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000328:Adult; D002104:Cadmium / Q000097:blood*; D002118:Calcium / Q000097:blood*; D016022:Case-Control Studies; D003300:Copper / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007501:Iron / Q000097:blood*; D007854:Lead / Q000097:blood*; D008274:Magnesium / Q000097:blood*; D011247:Pregnancy / Q000097:blood*; D012016:Reference Values; D055815:Young Adult; D015032:Zinc / Q000097:blood*
chemical_list: D002104:Cadmium; D007854:Lead; D003300:Copper; D007501:Iron; D008274:Magnesium; D015032:Zinc; D002118:Calcium