Maternal Urinary Bisphenol A during Pregnancy and Maternal and Neonatal Thyroid Function in the CHAMACOS Study

Jonathan Chevrier,¹ Robert B. Gunier,¹ Asa Bradman,¹ Nina T. Holland,¹ Antonia M. Calafat,² Brenda Eskenazi,¹ and Kim G. Harley¹

¹Center for Children’s Environmental Health Research, School of Public Health, University of California, Berkeley, Berkeley, California, USA; ²Division for Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA


Abstract

Background: Bisphenol A (BPA) is widely used in the manufacture of polycarbonate plastic bottles, food and beverage can linings, thermal receipts, and dental sealants. Animal and human studies suggest that BPA may disrupt thyroid function. Although thyroid hormones play a determinant role in human growth and brain development, no studies have investigated relations between BPA exposure and thyroid function in pregnant women or neonates.


Objective: Our goal was to evaluate whether exposure to BPA during pregnancy is related to thyroid hormone levels in pregnant women and neonates.


Methods: We measured BPA concentration in urine samples collected during the first and second half of pregnancy in 476 women participating in the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. We also measured free thyroxine (T₄), total T₄, and thyroid-stimulating hormone (TSH) in women during pregnancy, and TSH in neonates.


Results: Associations between the average of the two BPA measurements and maternal thyroid hormone levels were not statistically significant. Of the two BPA measurements, only the one taken closest in time to the TH measurement was significantly associated with a reduction in total T₄ (β = –0.13 µg/dL per log₂ unit; 95% CI: –0.25, 0.00). The average of the maternal BPA concentrations was associated with reduced TSH in boys (–9.9% per log₂ unit; 95% CI: –15.9%, –3.5%) but not in girls. Among boys, the relation was stronger when BPA was measured in the third trimester of pregnancy and decreased with time between BPA and TH measurements.


Conclusion: Results suggest that exposure to BPA during pregnancy is related to reduced total T₄ in pregnant women and decreased TSH in male neonates. Findings may have implications for fetal and neonatal development.


Key words: bisphenol A, endocrine disruption, neonates, pregnancy, thyroid hormone. 


Environ Health Perspect 121:138–144 (2013). http://dx.doi.org/10.1289/ehp.1205092 [Online 4 October 2012]


Address correspondence to J. Chevrier, Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, 1995 University Ave., Suite 265, Berkeley, CA 94704-7392 USA. Telephone: (510) 642-8917. Fax: (510) 642-9083. E-mail: chevrier@berkeley.edu


Supplemental Material is available online (http://dx.doi.org/10.1289/ehp.1205092).


We gratefully acknowledge M. Vedar for her important contributions, and X. Ye, X. Zhou, T. Jia, and R. Hennings for technical assistance in measuring the urinary concentrations of BPA. 


This publication was supported by grants RD 83171001 from the U.S. Environmental Protection Agency and RC ES018792 and P01 ES009605 from the National Institute of Environmental Health Sciences. Additional funding was provided by the University of California Institute for Mexico and the United States and the University of California Berkeley Center for Latino Policy Research. 


The contents of this publication are solely the responsibility of the authors and do not necessarily represent funders’ or the Center for Disease Control and Prevention’s official views. 


The authors declare they have no actual or potential competing financial interests.


Received 13 February 2012; Accepted 25 September 2012; Online 4 October 2012.