Chemicals, Early Brain Development, Autism and Other Disorders

A French research team has published new research linking thyroid hormone disruptors 20150317_CDC_Concussionto fetal and infant brain development disorders including Autism and attention deficit disorders.(1,2)

The thyroid hormone is fundamental to brain development. (3) In the first trimester, all of the thyroid hormone (T4) required for fetal brain development is provided by the mother. If the mother is deficient in this hormone, the brain development will be impaired, resulting in neurological deficits of several possible forms.

Thyroid hormones play a critical role in fetal brain development. The fetus depends entirely on maternal thyroid hormones for the first 12 weeks of pregnancy, until the baby’s thyroid begins to produce thyroid hormones on its own. For the first trimester the baby is completely dependent on the mother for thyroid hormones necessary for brain development. Babies born to mothers with undiagnosed or inadequately treated hypothyroidism are at risk for lower IQ scores and learning disabilities. Despite the mounting evidence, thyroid screening is currently NOT mandatory in pregnancy.(4)

Thyroid disruptors are chemicals that can reduce the level of the thyroid hormone or impair its functioning. In a National Institutes of Health review article from 2012, these are identified as including PCBs, phthalates, bisphenol A, brominated flame retardants and perfluorinated chemicals. (5)

Perflourinated chemicals (PFCs) are common in the human environment, although their use has been in decline over the last two decades. According to the Canadian National Collaborating Center for Environmental Health,

PFCs are man-made chemicals used in a wide arangeof applications as stain, grease, and water repellants. PFCs are found in fast food packaging, paper plates, stain-resistant carpets, carpet cleaning solutions, windshield washing fluid and fire-fighting foam, as well as in some adhesives, cosmetics, pharmaceuticals, electronics, cleaning products, polishes and waxes.(6)

Chemical and Engineering News reported in 2016 that remnants of PFCs exist in drinking water consumed by millions of Americans, and larger numbers overseas.(7) Parkersburg, WV, is identified as one of the hotspots for PFCs because it was the site for the manufacture of Teflon, used in cookware and other products across the US. DuPont agreed to a $107.6 million settlement over health claims related to Teflon. The DuPont spinoff, Chemours, faces 3,500 personal injury lawsuits related to PFCs.

The EPA in 2016 issued an advisory calling on water utilities to notify customers when there are excess amounts of some types of PFCs in drinking water. However, the advisory is voluntary, with no enforcement.(8)

The EPA followed this with a “health advisory” to water utilities in 2017. (10) As noted on the EPA site, these advisories are not enforceable.

So what are the French telling us now?

Prof Barbara Demeneix comments, “We have reviewed the documented exposures of pregnant women and children to mixtures of thyroid-hormone-disrupting chemicals and propose that the data sets provide a plausible link to the recent increased incidence of neurodevelopmental conditions, including autism spectrum disorders and attention deficit hyperactivity disorders.”

Bottom line: For your health and your childrens‘ health, you need to know what you are drinking. Your Federal, state and local governments aren’t in most cases doing what they need to do to protect you. At least not in the US.


  1. Bilal B Mughal, Jean-Baptiste Fini, Barbara Demeneix. Thyroid disrupting chemicals and brain development: an update. Endocrine Connections, 2018; EC-18-0029 DOI: 10.1530/EC-18-0029
  2. Society for Endocrinology. “Brain development disorders in children linked to common environmental toxin exposures.” ScienceDaily. ScienceDaily, 24 March 2018. <>.
  3. Gabriella de Escobar et. al., “Role of thyroid hormone in early brain development,” European Journal of Endocrinology, 2004, 151.
  6. ClenysWebster, “Potential human health effects of perfluorinated chemicals (PFCs)”, National Collaborating Center for Environmental Health, October 2010.
  7. Jessica Morrison, “Perfluorinated chemicals taint drinking water,” Chemical and Engineering News, v.94, 20, 16 May 2016.


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