Air pollution can impact babies in the womb

When a pregnant woman breathes a polluted air, soot particles can reach her baby's placenta, according to a new study.

The study, presented Sunday at the International Congress of the European Respiratory Society, adds to existing evidence on the dangers of air pollution for unborn babies.

Previous research has shown links between pregnant women exposed to air pollution during pregnancy and premature birth, low birth weight, infant mortality and respiratory problems in children.

"We have known for some time that air pollution affects the development of the fetus and can continue to affect babies after birth and throughout their lives," said Dr. Lisa Miyashita, a postdoctoral researcher.

"We were interested to see if these effects could be due to pollution particles moving from the mother's lungs to the placenta. Until now, there was very little evidence that inhaled particles enter the blood through the lungs.

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The researchers worked with five pregnant women living in London who planned cesarean deliveries at Royal London Hospital. All five were non-smokers with uncomplicated pregnancies and each gave birth to a healthy baby. The women allowed the researchers to study their placentas after childbirth.

The study looked at a particular group of cells called placental macrophages. Macrophages exist in many parts of the body as part of its immune system. They work by including harmful particles such as bacteria and pollution particles and, in the placenta, they help protect the fetus.

Using a high power microscope to examine 3,500 placental macrophage cells from the five female placentas, the team found 60 cells that contained 72 small black areas between them that were assumed to be carbon particles. On average, each placenta contained about five square micrometers of this dark substance.

The researchers then further investigated placental macrophages from two placentas using an electron microscope.

In previous research, the team used the same techniques to identify and measure soot particles in people's airways. By studying macrophages in other organs, says researcher Norrice Liu, they were looking for direct evidence that "inhaled particles" could move from the lungs to other parts of the body.

"We did not know if we were going to find particles and if we found them, we were only expecting to find a small number of placental macrophages that contained these soot particles," said Dr. Liu. "Our results provide the first evidence that inhaled pollution particles can move from the lungs to the circulation and then to the placenta.

"We do not know if the particles we found could also move in the fetus, but our evidence suggests that this is indeed possible. We also know that particles do not need to enter the baby's body to have an adverse effect because if they have an effect on the placenta, this will have a direct impact on the fetus. "

Professor Mina Gaga, president of the European Respiratory Society, who did not participate in the study, said: "This new research suggests a possible mechanism of how babies are affected by pollution while theoretically protected in the womb. This should educate clinicians and the public about the harmful effects of air pollution on pregnant women.

"We need stricter policies for cleaner air to reduce the impact of pollution on health worldwide, as we are already seeing a new population of young adults with health problems."

How to know the current level of air pollution in your area:

You can find out the current level of air pollution in your area by going to the Defra website, where you can click on a colored area on the map to display information. The results are based on the maximum air quality index measured at all stations in each region.

The color code highlights pollution levels from 'low' to 'very high'. Click here to find out what level of pollution you live in. Or for up-to-date alerts, follow the tweets on Twitter.

Defra advises people to use the air quality index to determine if they or their children are likely to be exposed to air pollution and to consult their doctor if necessary.