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Study Details
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Information Source
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Chevrier, J., et al. 2007. "Associations between Prenatal Exposure to Polychlorinated Biphenyls and Neonatal Thyroid-Stimulating Hormone Levels in a Mexican-American Population, Salinas Valley, California." Environmental Health Perspectives 115(10):1490-1496. |
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| Age when Exposed* age description below |
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| Age when Assessed* age description below |
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| Chemical | Polychlorinated Biphenyls (PCBs) | |||||
| Exposure Source | Agricultural | |||||
| Exposure Medium | Multiple/Not Specified | |||||
| Exposure Route | Multiple/Not Specified | |||||
| Species | Human | |||||
| Study Description and Health Effects/Endpoints |
This large study evaluated a possible association between prenatal polychlorinated biphenyl (PCB) exposure and thyroid stimulating hormone (TSH) levels in newborns. TSH had been shown to play a role in neurodevelopment. There was no significant association between the 34 summed PCB concentrations in maternal blood and neonatal TSH levels. There was a significant association between increased maternal concentrations of microsomal enzyme-inducing PCB congeners (ME-PCBs) and increased infant TSH levels (p<0.05). There was a 29% increase in TSH concentrations (95% confidence interval: 2-62%) for each 10-fold level increase in ME-PCB concentrations. The authors concluded that PCB congeners should be grouped by mechanism of action when measuring effects on thyroid hormones. |
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| Exposure Information and Comments/Notes |
Blood samples were collected from 285 women ages 18-45 and their infants. Maternal samples were collected in the 2nd trimester of pregnancy and shortly before delivery. Subjects lived in the Salinas Valley, California. This study was part of the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study. Concentrations of 34 PCB congeners were measured in maternal serum during the second trimester and before delivery. Concentrations of thyroid hormone (TSH) were measured in the blood of neonates 4-121 hours post-delivery. The mean ME-PCB concentration measured in maternal serum during pregnancy was 38.9 ng/g (range 10.0-250.3). |
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| Editorial Comments | none |
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