Maternal and fetal exposure to cadmium, lead, manganese and mercury: The MIREC study

• Published in: Chemosphere (Oxford) Vol. 163; pp. 270 - 282
• Main Authors: Arbuckle, Tye E., Liang, Chun Lei, Morisset, Anne-Sophie, Fisher, Mandy, Weiler, Hope, Cirtiu, Ciprian Mihai, Legrand, Melissa, Davis, Karelyn, Ettinger, Adrienne S., Fraser, William D.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-11-2016
• Subjects: Adult; Biomonitoring; Blood; Cadmium; Cadmium - blood; Calcium - chemistry; Canada; Cohort Studies; Female; Fetal Blood - drug effects; Humans; Infant; Ions; Lead; Lead - blood; Limit of Detection; Manganese; Manganese - blood; Maternal Exposure; Meconium; Mercury; Mercury - blood; Nutrient intake; Pregnancy; Surveys and Questionnaires; Vitamin D - chemistry; ANW, Canada; Pregnancy; Cadmium; Biomonitoring; Nutrient intake; Meconium; Lead; Mercury; Blood; Manganese
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2016.08.023

Given the susceptibility of the fetus to toxicants, it is important to estimate their exposure. Approximately 2000 pregnant women were recruited in 2008–2011 from 10 cities across Canada. Cd, Pb, Mn and total Hg were measured in maternal blood from the 1st and 3rd trimesters, umbilical cord blood, and infant meconium. Nutrient intakes of vitamin D, iron, and calcium (Ca) were assessed using a food frequency questionnaire and a dietary supplement questionnaire.
Median concentrations in 1st trimester maternal blood (n = 1938) were 0.20, 8.79 and 0.70 μg/L for Cd, Mn and Hg, respectively, and 0.60 μg/dL for Pb. While the median difference between the paired 1st and 3rd trimester concentrations of Cd was 0, there was a significant decrease in Pb (0.04 μg/dL) and Hg (0.12 μg/L) and an increase in Mn (3.30 μg/L) concentrations over the course of the pregnancy. While Cd was rarely detected in cord blood (19%) or meconium (3%), median Pb (0.77 μg/dL), Mn (31.87 μg/L) and Hg (0.80 μg/L) concentrations in cord blood were significantly higher than in maternal blood. Significant negative associations were observed between estimated Ca intake and maternal Cd, Pb, Mn and Hg, as well as cord blood Pb. Vitamin D intake was associated with lower maternal Cd, Pb, and Mn as well as Pb in cord blood.
Even at current metal exposure levels, increasing dietary Ca and vitamin D intake during pregnancy may be associated with lower maternal blood Pb and Cd concentrations and lower Pb in cord blood.
•Distribution of metals between maternal and cord blood differed by metal.•Cadmium was rarely detected in cord blood (19%) or meconium (3%).•Median cord Pb and Hg significantly higher than in maternal blood.•Manganese increased over the course of the pregnancy and highest in cord blood.•Higher Ca and vitamin D intake during pregnancy may lower maternal and cord Pb.