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Maternal and cord-blood thyroid hormone levels and exposure to polybrominated diphenyl ethers and polychlorinated

Nadia Abdelouahab1, Marie-France Langlois, Laetiscia Lavoie

  • 1Department of Pediatrics, Faculty of Medicine, University of Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Quebec, Canada.

American Journal of Epidemiology
|August 9, 2013
PubMed

Insights

Exposure to polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) during pregnancy may disrupt maternal and fetal thyroid hormone levels, potentially impacting neurodevelopment. Further research is needed to confirm these associations.

Area of Science:

  • Environmental Health
  • Endocrinology
  • Neuroscience

Background:

  • Thyroid hormones are crucial for organ growth, particularly brain development.
  • Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are environmental contaminants known to interfere with thyroid pathways.
  • Disruption of thyroid hormone homeostasis during pregnancy can negatively affect neurodevelopment.

Purpose of the Study:

  • To investigate the association between maternal exposure to PBDEs and PCBs in early pregnancy and thyroid hormone levels.
  • To examine thyroid hormone levels in both maternal and umbilical-cord blood.
  • To assess the impact of these environmental contaminants on thyroid hormone homeostasis during gestation.

Main Methods:

  • Prospective study involving 380 pregnant women in their first trimester.
  • Measurement of maternal blood levels of PBDEs, PCBs, thyroid hormones (T3, T4), thyroid-stimulating hormone, and other relevant biomarkers.
  • Assessment of thyroid hormone levels in maternal blood at delivery and in umbilical-cord blood.

Main Results:

  • In lipid-based models during early pregnancy, maternal PBDEs showed an inverse association with total triiodothyronine (T3) and thyroxine (T4), and a direct association with free T3 and free T4.
  • At delivery, negative associations were observed between maternal total T4, free T3, cord-blood free T4, and PBDEs.
  • Maternal free T3 also showed a negative association with PCBs at delivery.

Conclusions:

  • Maternal exposure to PBDEs and PCBs during pregnancy may interfere with thyroid hormone levels.
  • These findings suggest a potential mechanism by which environmental contaminants could impact thyroid hormone homeostasis.
  • Further investigation is warranted to understand the long-term implications for neurodevelopment.

Keywords:
cord bloodpolybrominated diphenyl etherspolychlorinated biphenylspregnancythyroid functionumbilical cord

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