Recent studies have shown that air pollution can affect the thyroid. Thyroid hormones play an important part in neurological development and are crucial for controlling fetal growth. Thyroxine, also known as T4, is the major thyroid hormone in circulation. TSH is the thyroid-stimulating hormonal hormone. A heel prick test is performed on newborns at 48 hours. This measures the levels of thyroxine in blood and TSH in the blood. The risk of developing serious illnesses increases if there is an imbalance in these thyroid hormones. Amaia Irizar Loibide, a researcher at the UPV/EHU Department of Preventive Medicine and Public Health, explained that this study aimed to examine the relationship between the amount of thyroxine in the infant and atmospheric pollution.Two of the most significant pollutants in relation to vehicle traffic and air pollution are nitrogen dioxide (NO 2) and fine particulate matter (PM2.5). PM2.5 particles, for example, are extremely fine and can easily enter the respiratory system. We specifically examined the effects of maternal exposure to fine particles during pregnancy, as well as the relationship with thyroxine levels at newborn babies. Because the development of the foetus is variable from week to week, we have been keeping an eye on it weekly. We did the most thorough research to determine which weeks are most sensitive to pregnancy," said the UPV/EHU researcher.The INMA (Environment and Childhood Project) sample from Gipuzkoa was therefore analysed. Data on air pollutants, including NO 2, PM2.5, and TSH, as well as data from neonatal heels on T4 and TSH levels, were all analysed. The data collected during the project was also used.Amaia Irizar stated that "the direct relationship between fine particles in pregnancy and newborns' levels of thyroxine has been established." We have not seen any clear evidence linking nitrogen dioxide exposure. These findings are consistent with previous research. Irizar stated that the exposure in the first three months of pregnancy had a direct effect on the balance and function of the thyroid hormones. The babies with lower levels of thyroxine have a tendency to be healthier. We found that the relationship between mother and baby decreases as the pregnancy progresses. The mother's exposure to the hormone gradually decreases in importance. This link is evident again in late pregnancy. However, it has an opposite effect. As the concentration of fine particles rises, we have observed that thyroid hormones levels also increase, which has the opposite effect. It is unclear what mechanism is behind this. "In any case, we have concluded that the most sensitive times of pregnancy to atmospheric pollution are the late and early months," stressed the UPV/EHU researcher."The next task is to investigate the mechanisms through which these fine particles can cause opposing effects in late and early pregnancy. These particles are actually small spheres of carbon. It isn't clear if the particles have an effect on the baby because they pass through the placenta, or if other components are released after they enter the body. Amaia Irizar stated that we need to continue investigating whether pregnancy exposure affects thyroid hormones as well as other aspects like neuropsychological growth, weight, and obesity.
