China study on placental concentrations on heavy metals and the risk of neural tube defects

Monday, Jan 21, 2019


Jin L, Zhang L, Li Z, Liu JM, Ye R, Ren A. Placental concentrations of mercury, lead, cadmium, and arsenic and the risk of neural tube defects in a Chinese population. Reprod Toxicol. 2013 Jan;35:25-31. Link to PubMed

  • Background:
    A study to examine the risk of neural tube defects (NTDs) associated with utero exposure to heavy metals – mercury (Hg), cadmium (Cd), lead (Pb) and arsenic (As) in Chinese population.
  • Method:
    • Subjects – 80 newborns with NTDs (anencephaly or spina bifida) and 50 healthy term newborns (controls) recruited from Shanxi Province.
    • Concentrations of total Hg, Cd, Pb and As were measured from placentas collected at delivery or pregnancy termination.
  • Key findings:
    • Median Hg concentration – Significantly higher (p<0.001) in cases with any NTDs (2.25 ng/g) than the controls (1.16 ng/g)
    • Median Cd concentration – Significantly lower (p<0.001) in cases with any NTDs (3.85 ng/g) than the controls (7.64 ng/g).
    • No significant differences in both median concentrations of Pb and As between NTDs and control groups.
    • Dose-response pattern of Hg levels and risk of NTDs – 2.7-fold increased risk with Hg concentration of 1.21 to 2.32 ng/g; and 18.2-fold increased risk with Hg concentration of ≥ 2.32 ng/g.
  • Conclusion:
    • Higher placental concentrations of Hg were associated with increased risk of NTDs.

Additional reading:
Link to the RCOG's recommendation on reducing chemical exposure during pregnancy



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