Air pollution can have a multitude of adverse health consequences. The latter can lead to a reduction in respiratory capacity, increase the risk of lung cancer or even impact cardiovascular health. Recently, a team of French researchers wondered about the consequences of air pollution on the development of children during pregnancy.
More precisely, researchers from Inserm and Grenoble University looked at how three air pollutants can impact the DNA of the placenta. According to them, this can negatively impact the child’s development. For girls, it increases the risk of chronic illness and for boys, it delays intellectual development. Their results are published in The Lancet Planetary Health.
The placenta would help determine the child’s prenatal environment
To arrive at these results, the researchers based themselves on a panel of nearly 1,500 pregnant women from three French study groups. Researchers were interested in the impact of three air pollutants: nitrogen dioxide (NO2), and fine particles (PM2.5 and PM10) on child development.
To do this, they focused on the consequences of air pollution on the placenta. It’s an organ “particularly vulnerable to numerous chemical compounds, it can be compared to an ‘archive’ testifying to the child’s prenatal environment”, write the researchers in a press release. To do this, the researchers studied the level of DNA methylation. This is one “of the best known epigenetic mechanisms involved in the control and expression of genes”.
Height, weight… Air pollution impacts child development
The researchers found that exposure to these three pollutants had “a significant impact”on “Placental DNA methylation levels of genes involved in fetal development”. More precisely, “a third of these modifications were directly associated with indicators of child development (birth weight and height, head circumference, length of pregnancy, etc.)”, note the researchers.
Among other changes linked to the placenta, the authors note changes concerning “the development of the nervous system, the immune system and metabolism – including genes involved in the occurrence of neonatal diabetes or obesity”. Researchers also note some differences in the consequences of air pollution depending on the sex of the child.
Girls and boys would be impacted differently by air pollution
Indeed, according to the results, boys and girls are not affected in the same way by air pollution. Boys would be particularly vulnerable during the first trimester of pregnancy while girls would be particularly vulnerable during the third trimester of pregnancy.
For girlsthe impacted methylations were linked to “genes involved in fetal development and the regulation of oxidative stress”. According to the authors, this is characterized by a increased risk of certain chronic metabolic diseases such as hypertension, diabetes or obesity. In addition, it increases the risk of miscarriage or pre-eclampsia.
In boys, the authors found that impacted methylations were linked to the development of the nervous system and intellect.
“Our results show that exposure to air pollution during pregnancy induces changes in placental DNA methylation specific to each of the two sexes, underlines Johanna Lepeule, Inserm researcher, within the Institute for the Advancement of Biosciences, and the specialist to emphasize that this differentiated impact could contribute to alterations in the development and course of pregnancy that are different depending on the sex of the unborn child”.
Researchers call for further research to “to investigate whether placental epigenetic changes caused by exposure to air pollution during pregnancy persist after delivery and how they might influence development during childhood.”
Sources:
- Vulnerability of the placenta to air pollution: what effects on the development of the unborn child? – Inserm
- The Lancet Planetary Health, May 7, 2024