Soot found in placenta of London mothers

Discovery of carbon traces prompts scientists to warn that unborn babies in some areas have high health risk

Soot particles have been discovered in the placentas of pregnant women for the first time, leading scientists to warn that pollution may directly harm unborn babies. Researchers at Queen Mary University of London discovered carbon particles in the organs of five mothers-to-be living in the capital. The discovery helps to explain data suggesting women living in polluted areas are more prone to giving birth prematurely and to having babies with low birthweight.

SOOT particles have been discovered in the placentas of pregnant women for the first time, leading scientists to warn that pollution may directly harm unborn babies. Researchers discovered small black areas in the organ that surrounds the foetus in five mothers-to-be who were living in London.

Until now there has only been limited evidence that inhaled pollution particles can access the bloodstream via the lungs.

But the discovery of carbon particles in an organ so crucial for pregnancy helps explain data suggesting that women living in polluted areas are more prone to premature birth and having low-birthweight babies. Scientists at Queen Mary University of London worked with five pregnant women living in the capital due to have planned caesarean section deliveries at the Royal London Hospital.

They studied 3,500 macrophages, immune system cells that engulf harmful particles, finding that 60 cells that between them contained 72 small black areas, which they believe indicate carbon particles. On average, each placenta contained around five square micrometres of this black substance.

“We’ve known for a while that air pollution affects foetal development and can continue to affect babies after birth and throughout their lives,” said Dr Lisa Miyashita, who led the study.

“We were interested to see if these effects could be due to pollution particles moving from the mother’s lungs to the placenta.”

The placenta is an organ attached to the lining of the womb during pregnancy that links the mother to the unborn baby but keeps the baby’s blood supply separate from the mother’s.

Oxygen and nutrients pass from the mother’s blood supply into the placenta through the umbilical cord to the foetus, and takes away waste products.

In previous research, the team used the same techniques to identify and measure these sooty particles in macrophages in people’s airways.

Dr Norrice Liu, a paediatrician and research fellow, added: “Our results provide the first evidence that inhaled pollution particles can move from the lungs into the circulation and then to the placenta. 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 that particles do not need to get into the baby’s body in order to be harmful because simply affecting the placenta directly impacts the foetus.

Prof Mina Gaga, president of the European Respiratory Society, where the study was presented, said: “We need stricter policies for cleaner air to reduce the impact of pollution on health worldwide because we are already seeing a new population of young adults with health issues.”