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Long-term Behavioral and Reproductive Consequences of Embryonic Exposure to Low-dose Toxicants
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Birth delivery mode modifies the associations between prenatal polychlorinated biphenyl (PCB) and polybrominated

Julie B Herbstman1, Andreas Sjödin, Benjamin J Apelberg

  • 1Columbia Center for Children's Environmental Health, Department of Environmental Health Sciences, Columbia Mailman School of Public Health, New York, New York 10032, USA. jh2678@columbia.edu

Environmental Health Perspectives
|October 23, 2008
PubMed

Insights

Prenatal exposure to PCBs and PBDEs may lower thyroid hormones in infants born vaginally. Intrapartum stress might mask these chemical effects on developing babies.

Area of Science:

  • Environmental Health
  • Endocrinology
  • Toxicology

Background:

  • Developing infants are vulnerable to endocrine disruption from environmental chemicals.
  • Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are common chemical contaminants.
  • These chemicals may interfere with critical hormone development in newborns.

Purpose of the Study:

  • To examine the association between cord serum levels of PCBs and PBDEs and thyroid hormone levels in infants.
  • To investigate thyroid hormone measurements in both cord blood serum and neonatal blood spots.
  • To explore the influence of delivery mode as a factor in hormone disruption.

Main Methods:

  • Measured PCBs and PBDEs, thyrotropin (TSH), thyroxine (T4), and free T4 (FT4) in cord blood serum from 297 infants.
  • Abstracted total T4 (TT4) from neonatal blood spot samples.
  • Utilized delivery mode as a proxy for intrapartum stress, known to affect thyroid hormones.

Main Results:

  • No overall association found between chemical exposures and average TSH, FT4, or TT4 in the full cohort.
  • Specific PBDEs (BDE-100, BDE-153) were linked to increased odds of low cord TT4 and FT4.
  • In infants born via spontaneous vaginal delivery, PCBs were associated with lower cord TT4 and FT4, and PBDEs showed negative trends.

Conclusions:

  • Prenatal exposure to PCBs and PBDEs is associated with reduced TT4 and FT4 levels in infants born by spontaneous vaginal delivery.
  • The hormonal effects of these chemical exposures may be masked by intrapartum stress related to delivery mode.
  • Findings highlight the potential impact of environmental contaminants on infant thyroid hormone levels, particularly in the absence of significant delivery stress.
Abstract

Keywords:
childrencord bloodendocrine disruptionenvironmental healthpolybrominated diphenyl etherspolychlorinated biphenylsthyroid hormones

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