The study, conducted by researchers at Queen Mary University of London, adds to an existing body of evidence linking pregnant mothers’ exposure to air pollution with issues including premature birth and childhood respiratory problems.
“We’ve known for a while that air pollution affects foetal development and can continue to affect babies after birth and throughout their lives… [But] until now, there has been very little evidence that inhaled particles get into the blood from the lung,” Dr Lisa Miyashita, who worked on the study, said in a statement.
To conduct the study, the scientists used the placentas of five non-smoking women in London, who had all delivered healthy babies via planned caesarean sections.
Using a high-powered microscope, they analysed 3,500 macrophage cells, which form part of the body’s immune system and engulf harmful particles such as air pollution.
Within the cells, they found 72 small black areas that they believed to be carbon particles.
“Our results provide the first evidence that inhaled pollution particles can move from the lungs into the circulation and then to the placenta,” said Dr Norrice Liu, who presented the research at the European Respiratory Society International Congress on Sunday.
“We do not know whether the particles we found could also move across into the foetus, but our evidence suggests that this is indeed possible,” she added.
Professor Mina Gaga, president of the European Respiratory Society, said the research, which she was not involved in, “suggests a possible mechanism of how babies are affected by pollution while being theoretically protected in the womb.”
“This should raise awareness amongst clinicians and the public regarding the harmful effects of air pollution in pregnant women,” she added.