title: Evaluation of lead and essential elements in whole blood during pregnancy: a cross-sectional study.
abstract: OBJECTIVE
  Physiological concentrations of some elements fluctuate during pregnancy due to the increased requirements of growing fetus and changes in the maternal physiology. The aim of the study is to evaluate the distribution at different stages of pregnancy in healthy Chinese women and to show the association between trace elements and gestational age-specific reference intervals.
  
  
  METHODS
  A cross-sectional study was performed in 1089 pregnant women and 677 nonpregnant control women. Five element concentrations, including Cu, Zn, Ca, Mg, Pb in the blood were determined by atomic absorption spectrometry. Spearman's rank correlation test was used to assess the relationship between weeks of gestation and blood element concentrations.
  
  
  RESULTS
  The mean levels of Cu and Mg were 23.64 ± 4.69 μmol/L and 1.36 ± 0.12 mmol/L, respectively, in the control women. While 0.68 % of all pregnant women showed Cu levels below the normal ranges, the levels of Mg were comparable in different groups. Though the overall mean blood zinc and Ca concentrations (83.84 ± 17.50 μmol/L and 1.60 ± 0.15 mmol/L, respectively) increased gradually with the progress of gestation, the Zn and Ca deficiency levels (16.6 and 3.6 %, respectively) decreased with the advance of gestation. Compared with nonpregnant group, the concentrations of Cu, Zn, Ca, Mg, Pb during the different stages of pregnancy, as a whole, were significantly different. Positive correlations were observed between weeks of gestation and blood Cu, Ca, Pb concentrations (r = 0.301, 0.221, 0.223; P < 0.05). There was a negative correlation blood Mg concentrations and weeks of gestation (r = -0.321; P < 0.05). A weak positive correlation was noted between Zn concentrations and weeks of gestation (r = 0.125; P < 0.05).
  
  
  CONCLUSIONS
  The importance of Cu and Mg deficiency and supplementation is well realized, but, Zn/Ca deficiency and Pb exposure is still exist; the overall deficiency of pregnant women was not so optimistic. During pregnancy, the established reference values will provide an important guidance for the reasonable supplementation of essential elements and surveillance of lead overexposure.
authors.affiliation: Department of Clinical Laboratory, State Key Laboratory of Reproductive Medicine, Nanjing Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University, Nanjing, 210029, China.
authors.forename: K
authors.initials: K
authors.lastname: Liu
authors.affiliation: Endocrine and Diabetes Center, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing University of Traditional Chinese Medicine, Jiangsu Branch of China Academy of Chinese Medical Science, No. 100 Hongshang Road, Nanjing, 210028, China.
authors.forename: X
authors.initials: X
authors.lastname: Mao
authors.affiliation: Department of Maternity and Child Health Care, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China.
authors.forename: J
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Obstetrical, Nanjing Maternity and Child Health Care Hospital, Nanjing, 210004, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Endocrine and Diabetes Center, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing University of Traditional Chinese Medicine, Jiangsu Branch of China Academy of Chinese Medical Science, No. 100 Hongshang Road, Nanjing, 210028, China. Jsdxjsxynj@163.com.
authors.forename: C
authors.initials: C
authors.lastname: Liu
mesh_terms: D000328:Adult; D002118:Calcium / Q000097:blood; D016022:Case-Control Studies; D003300:Copper / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D008274:Magnesium / Q000097:blood; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood; D011262:Pregnancy Trimester, Second / Q000097:blood; D012016:Reference Values; D013054:Spectrophotometry, Atomic; D014131:Trace Elements / Q000097:blood*; D055815:Young Adult; D015032:Zinc / Q000097:blood
chemical_list: D014131:Trace Elements; D003300:Copper; D008274:Magnesium; D015032:Zinc; D002118:Calcium
keywords: Blood copper; Calcium; Duration of pregnancy; Lead; Magnesium; Zinc