Blood heavy metal concentrations in pregnant Korean women and their children up to age 5 years: Mothers’ and Children's Environmental Health (MOCEH) birth cohort study

The present study assessed the associations of heavy metal concentrations in pregnant women with the concentrations in their children during early childhood. This study is a part of the Mothers’ and Children's Environmental Health (MOCEH) study, a Korean multi-center prospective birth cohort study of 1751 pregnant women who were recruited from 2006 to 2010. We completed the follow-up of children who were 5 years-old in 2016. Lead, total mercury, and cadmium were measured in women during early and late pregnancy, in cord blood, and in children who were 2, 3, and 5 years-old. Lead concentration was lowest in cord blood, highest in 24 month-old children, and then decreased with child age. Total mercury concentration was highest in cord blood, and gradually decreased with child age. Cadmium concentration was lowest in cord blood, and increased with child age. After adjusting for child sex, maternal age, and maternal education level, we found strong correlations between the levels of lead and total mercury in women during late pregnancy with the levels in cord blood; however, there were weak correlations between the levels of these metals in women during late pregnancy and cord blood with the levels in their children. In conclusion, maternal lead and mercury concentrations correlated with the levels in cord blood and in children up to age 60 months. This correlation may be due to high trans-placental transmission of these metals and shared living environment such as environmental exposure, food consumption, and lifestyle.