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

Abstract

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.

Maternal blood cadmium, lead and arsenic levels, nutrient combinations, and offspring birthweight

“…Our data however contrast with in vitro evidence that show >50% lower Cd levels with Zn and Mn treatment, and negative relationships between Zn, Cu and Mg with Cd [62]. These data provide early evidence that some essential metals, including Mn [63] may not mitigate exposure and effects of these metals. Specific mineral combinations that mitigate exposure may depend on the underlying nutritional status and may therefore vary by population exposed to Pb or Cd.…”

Early-life chemical exposures and risk of metabolic syndrome

“…For the general population, the most common sources of exposure for these heavy metals are via contaminated air and food, although exposure to tobacco smoke is also a significant source of exposure for cadmium and lead 116,117. Although lead levels have been continuously decreasing in North America,118 a recent study found that >99% of women had detectable blood lead levels during pregnancy 119. Similarly, the majority of pregnant women had detectable blood levels of cadmium (>95%) and mercury (>85%) 119.…”

“…Although lead levels have been continuously decreasing in North America,118 a recent study found that >99% of women had detectable blood lead levels during pregnancy 119. Similarly, the majority of pregnant women had detectable blood levels of cadmium (>95%) and mercury (>85%) 119. Given the widespread exposure to cadmium, mercury, and lead, there have been a number of studies investigating the relationship between maternal body burden of these metals and adverse pregnancy outcomes (eg, spontaneous abortion, stillbirth, preterm labor, and low birth weight).…”

Effects of Prenatal Exposure to Endocrine Disruptors and Toxic Metals on The Fetal Epigenome

“…Therefore, the placenta provides a partial barrier against this metal [20]. As a result, Cd levels in cord blood are typically lower than maternal Cd levels [40]. Nevertheless, in utero Cd exposure has been linked to a range of adverse health effects, including impaired growth and neurodevelopment [41][42][43].…”