A new study shows that soot particles are able to reach the placenta through the bloodstream, further evidence that air pollution is dangerous for unborn babies.
Previous research had already revealed associations between the exposure of pregnant women to air pollution and premature births, low birth weight, infant mortality and respiratory problems in children.
This time around, a new study, presented at the European Respiratory Society International Congress, shows that the soot particles are able to reach the placenta through the bloodstream, in pregnant women who breathe too polluted air. “We have known for some time that air pollution affects fetal development and can continue to affect babies after birth, throughout their lives. We wanted to know if these effects could be due to particles of pollution moving from the mother’s lungs to the placenta. So far there has been very little evidence that inhaled particles enter the bloodstream through the lungs, “says Dr Lisa Miyashita (Queen Mary University, London) , co-author of the research.
The placenta of 5 women
Her team studied the placenta of 5 women after giving birth. All were non-smokers, had no complications during their pregnancy, and gave birth to healthy babies.
The researchers were interested in cells called “placental macrophages”. Found in many parts of the body, macrophages participate in the immune system by absorbing harmful particles, such as bacteria and polluting particles. In the placenta, they especially help protect the fetus.
3,500 placental macrophage cells – from the five placentas – were examined under a microscope. The researchers found 60 cells, which alone contained 72 small black areas, which they said corresponded to carbon particles. On average, each placenta contained about five square micrometers of said toxic substance.
Moving from the lungs to the circulation
“We have the first evidence that inhaled pollution particles can pass from the lungs to the circulation and then to the placenta. We don’t know if the particles we found can also travel in the fetus, but we believe it is. Anyway, the particles do not need to enter the baby’s body to have a bad effect, because if they have an effect on the placenta, it will have a direct impact on the fetus “, concludes pediatrician and study co-author Norrice Liu. “
According to the World Health Organization (WHO), 9 out of 10 people breathe air containing high levels of pollutants. 7 million people die from it every year. “Air pollution is a threat to all of us, but the poorest and most marginalized populations are the first to suffer,” laments Dr Tedros Adhanom Ghebreyesus, Director-General of WHO. “We cannot accept that more than 3 billion people – mostly women and children – continue to breathe deadly fumes from polluting stoves and fuels every day. If we do not act quickly, development lasting will remain a pipe dream. “
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