It is not the first time that we echo the harmful effects of air pollution for pregnancy and for the development of the baby. Now, a study published in Environmental Research concludes that maternal exposure to air pollution during pregnancy can affect the growth of newborns. The stages most sensitive to air pollution are the first and last months of pregnancy.
Air pollution and vehicle traffic
According to studies in recent years, air pollution affects the thyroid. Thyroid hormones are essential for regulating fetal growth and metabolism and play an important role in neurological development. Thyroxine (T4) is the main circulating thyroid hormone and the thyroid stimulating hormone is TSH.
At 48 hours, newborn babies undergo a heel prick test in which blood levels of thyroxine and TSH are measured. In fact, if the balance of these thyroid hormones is not the right one, it increases the risk of developing serious diseases. For this reason, “this study set out to analyze the relationship between air pollution during pregnancy and the level of thyroxine in the newborn ,” explains Amaia Irizar-Loibide, researcher at the UPV / EHU Department of Preventive Medicine and Public Health.
Nitrogen dioxide (NO2) and fine particles less than 2.5 microns in diameter (PM2.5) are two of the main pollutants related to air pollution and vehicle traffic. PM2.5 particles, for example, are very fine and easily enter the respiratory tract. So the UPV / EHU researcher:
“In this work we specifically analyze the effect of maternal exposure to these fine particles and nitrogen dioxide during pregnancy and the link with thyroxine levels in newborns. We have been monitoring weekly, as the development of the fetus varies a lot from week to week. That is why we try to carry out the most detailed investigation possible to know which are the most sensitive weeks of pregnancy ”.
The sample of the INMA project (Environment and Children) in Gipuzkoa was analyzed. Data on air pollutants PM2.5 and NO2, data on TSH and T4 levels of neonatal heels, etc. were also used. collected in the project. According to Amaia Irizar, “the results obtained in this study have revealed a direct relationship between exposure to fine particles during pregnancy and the level of thyroxine in newborns. However, we have not observed a clear link with exposure to nitrogen dioxide . “
“What we have seen in this work is that exposure during the first months of pregnancy has a direct influence on the balance of thyroid hormones. These babies tend to have a lower level of thyroxine. As the pregnancy progresses, we find that this relationship gradually decreases, that is, the mother’s exposure gradually becomes less important.
However, at the end of pregnancy, this link becomes apparent, but shows the opposite effect: as the concentration of these fine particles increases, we have seen that the level of thyroid hormones also increases, which has the opposite effect on the Balance”.
Amaia Irizar-Loibide adds that “It is not clear what mechanism is behind all this.”
But according to the researcher there is still work to be done: “to study the mechanisms by which these fine particles cause opposite effects at the beginning and at the end of pregnancy and why they pass from the placenta to the baby, if other components attached to the particles are released a time they have entered the body… ”.
“We need to continue investigating whether exposure during pregnancy affects not only thyroid hormones, but also other aspects such as neuropsychological development, growth, obesity, and so on.”
Via | Basque Country University
In Babies and More | Exposure to pollution during pregnancy is associated with delayed growth of the child in its early years, Air pollution increases the risk of miscarriage and hinders natural pregnancy or in vitro fertilization
