Blood mercury concentrations in pregnant and nonpregnant women in the United States: National Health and Nutrition Examination Survey 1999-2006

National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
American journal of obstetrics and gynecology (Impact Factor: 4.7). 11/2013; 210(4). DOI: 10.1016/j.ajog.2013.10.884
Source: PubMed


Prenatal exposure to methylmercury is associated with adverse neurological development in children. We examined total blood mercury (BHg) concentrations and predictors of higher BHg concentrations in pregnant and non-pregnant women.
We analyzed data from 1,183 pregnant and 5,587 non-pregnant women aged 16-49 years from the 1999-2006 National Health and Nutrition Examination Survey (NHANES). We estimated geometric mean BHg concentrations and characteristics associated with higher mercury concentrations (≥3.5 μg/L) in crude and adjusted linear and logistic regression models.
After adjusting for age and race/ethnicity, geometric mean BHg concentrations were clinically similar but significantly lower for pregnant (0.81 μg/L, 95% confidence interval [CI]: 0.71, 0.91) and non-pregnant women of childbearing age (0.93 μg/L, 95% CI: 0.87, 0.99); 94% of pregnant and 89% of non-pregnant women had BHg concentrations below 3.5 μg/L. The most significant predictor of higher BHg concentrations for both pregnant and non-pregnant women was any seafood consumption vs. no consumption in the last 30 days (Odds ratio [OR]: 18.7, 95% CI: 4.9, 71.1; OR: 15.5, 95% CI: 7.5, 32.1, respectively). Other characteristics associated with ≥3.5 μg/L BHg concentrations were older age (35+ years), higher education (greater than high school), and higher family income to poverty ratio (3.501+) for both pregnant and non-pregnant women.
Pregnancy status was not strongly associated with BHg concentrations in women of childbearing age and BHg concentrations above the 3.5 μg/L cut were uncommon.

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