The first evidence of the presence of tiny carbon particles, generated by the combustion of fossil fuels, in the placenta comes from this study from Queen Mary University presented at the international congress of the European Respiratory Society. While previous research has found links between pregnant women's exposure to air pollution and premature birth, low birth weight, infant mortality and respiratory problems in children, these new data add existing evidence on the dangers of pollution to unborn babies.
"We have known for some time that air pollution affects fetal development and can continue to affect babies after birth and throughout their lives", recall the London researchers. "We wanted to test whether these effects can be linked to pollution particles moving from the mother's lungs to the placenta and clarify the route by which inhaled particles enter the bloodstream." Especially since the same team had, in previous research, identified and measured these carbon particles in macrophages in the respiratory tract. "We thought that looking at macrophages in other organs might provide direct evidence that inhaled particles move from the lungs to other parts of the body."
The research is carried out with 5 pregnant women who had to plan their delivery by cesarean section at the Royal London Hospital. These participants were non-smokers, had an uncomplicated pregnancy and delivered a healthy baby. They allowed researchers to study their placenta after they gave birth. The researchers looked at particular cells called placental macrophages. Macrophages that exist in many parts of the body are part of the immune system and work by engulfing harmful particles, such as bacteria and pollution particles. In the placenta, macrophages also help protect the fetus.
Each placenta contained about five square micrometers of substantia nigra …A total of 3,500 placental macroscopic cells from the 5 placentas were examined under a microscope. The researchers then identified 60 cells with 72 small "black areas" similar to carbon particles. On average, each placenta contained about five square micrometers of this black substance. Further analysis of placental macrophages from two placentas using an electron microscope identified materials they believed were made of tiny carbon particles.
Lungs, placenta blood, fetus: these results provide the first evidence that inhaled pollution particles can travel from the lungs to the circulation to reach the placenta. “We still don't know if the particles we found could also reach the fetus, but our evidence suggests that it is indeed possible. We also know that the particles do not need to enter the baby's body to have an adverse effect, because if they have an effect on the placenta, it will have a direct impact on the fetus”.
In short, this research suggests a possible mechanism for how babies are affected by pollution while theoretically being protected in the womb. Hoping that these data can raise awareness among politicians, clinicians and the public about the harmful effects of air pollution in pregnant women.
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