Environmental pollutants contain endocrine disruptors, which can affect the thyroid function of the expectant mother during pregnancy. However, this contributes to the development of the foetus.
- According to ANSES, endocrine disruptors are substances that disrupt the hormonal functioning of living organisms.
- Exposure to these pollutants can occur in three ways: by ingestion, by inhalation or by skin contact.
Many pregnancy ailments are hormone-related, such as food cravings or mood swings. However, these are essential at this particular moment of life. They allow the development of the fetus. A new study, carried out by researchers from Inserm and the University of Grenoble Alpes, shows that certain pollutants can cause hormonal imbalances. Their work, published in the specialist journal Environmental Health Perspectivesfocus on thyroid function.
Endocrine disruptors: “the participants were almost all exposed to them”
As a reminder, the thyroid is a small gland located at the base of the neck. It produces two hormones: triiodothyronine (or T3) and thyroxine (or T4), but their secretion is controlled by another hormone, thyroid stimulating hormone (or TSH) produced in the brain by another gland, the pituitary gland.
“These hormones are crucial for the development of the fetus. Thyroid dysfunction in pregnant women is therefore likely to impact the health of the unborn child.“, explain the authors in a communicated. However, pollutants present in the environment can have consequences on thyroid function. In this research, scientists focused on “the impact of exposure to molecules from the family of phenols, parabens and phthalates, considered chemical pollutants, on the concentrations of thyroid hormones in pregnant women“.
The team relied on biological samples from 437 pregnant women. “Several chemical pollutants were detected in the majority of the urine samples collected, which confirms that the participants were almost all exposed to them.”, they observe. However, these different molecules can disrupt the functioning of the thyroid.
Endocrine disruptors “could act on the degradation of thyroid hormones”
Exposure to propyl-paraben (a compound used as a preservative in the cosmetics, food and pharmaceutical industries) was associated with a decrease in T3 concentrations while butyl-benzyl phthalate (used in particular in PVC type plastics) was associated with increased T4 concentrations. Bisphenol A, notably used in the manufacture of plastic, was associated with a drop in TSH concentration.
“Data from in vitro toxicological tests suggest that these pollutants could act on the mechanisms governing the synthesis and degradation of thyroid hormones, emphasizes Claire Philippat, coordinator of this study. Butyl-benzyl phthalate and bisphenol A could in particular inhibit the incorporation of iodine – an essential element for the synthesis of thyroid hormones – in thyroid cells.“For her, these conclusions should alert, insofar as the population is frequently exposed to these different chemicals. With her team, she is continuing work on the subject, focusing on the impact of these changes in the function thyroid on neurodevelopment and growth in children.
#Communicated ????️ An international research consortium has studied the impact of exposure to molecules considered chemical pollutants (phenols, parabens and phthalates) on the concentrations of thyroid hormones in pregnant women.
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