Here's how air pollution affects foetal development

For the first time, researchers have found evidence of tiny particles of carbon, typically created by burning fossil fuels, in placentas.

Previous research indicated links between pregnant mothers' exposure to air pollution and premature birth, low birth weight, infant mortality and childhood respiratory problems. The new study, however, adds to existing evidence on the dangers of pollution for unborn babies and suggests that when pregnant women breathe polluted air, sooty particles are able to reach the placenta via the bloodstream.

The work was presented by Dr. Norrice Liu, and Dr. Lisa Miyashita, who said, "We've known for a while that air pollution affects foetal development and can continue to affect babies after birth and throughout their lives."

The team studied a total of 3,500 placental macrophage cells from the five placentas and examined them under a high-powered microscope. They found 60 cells that between them contained 72 small black areas that researchers believe were carbon particles. On average, each placenta contained around five square micrometres of this black substance.

They went on to study the placental macrophages from two placentas in greater details using an electron microscope and again found material that they believe was made up of tiny carbon particles.

The results provided the first evidence that inhaled pollution particles can move from the lungs into the circulation and then to the placenta.

Professor Mina Gaga, President of the European Respiratory Society said, "Previous research shows that pregnant women living in polluted cities are more prone to pregnancy issues such as restricted foetal growth, premature birth, and low birth weight babies. The evidence suggests that an increased risk of low birth weight can happen even at levels of pollution that are lower than the European Union recommended annual limit."

This new research suggests a possible mechanism for 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.

The research was presented at the European Respiratory Society International Congress 2018.