Scientists warn that inhaled air pollutant particles (particulate matter) are moving from the lungs to placentas of pregnant women, highlighting an urgent need for stricter policies for cleaner air that will lower impacts of pollution on health.
The new study presented at the European Respiratory Society International Congress 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 Norrice Liu, a paediatrician and clinical research fellow and Lisa Miyashita, a post-doctoral researcher, both members of Professor Jonathan Grigg's research group at Queen Mary University of London.
"We have known for a while that a correlation exists between maternal exposure to air pollution derived particulate matter and harmful effects on the foetus but the mechanisms behind this correlation remain to be unidentified. We, therefore, wanted to investigate whether particles travel to the placenta," Miyashita told Mongabay-India, adding that this study provides the first evidence that inhaled particulate matter (PM) translocate from the lung to the placenta.
The researchers examined the placentas of five pregnant women in the United Kingdom who were due to have planned caesarean section deliveries at the Royal London Hospital.
They were all non-smokers with an uncomplicated pregnancy and each one gave birth to a healthy baby. The women all gave permission for researchers to study their placentas after delivery, a press release said.
The researchers examined cells called placental macrophages. Macrophages exist in many different parts in the body. They are part of the body's immune system and work by engulfing harmful particles, such as bacteria and pollutant particles. In the placenta they also help protect the foetus.
"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. We also know that the particles do not need to get into 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 foetus."
They advise pregnant women to avoid heavily polluted areas where possible. "Stricter policies for cleaner air will reduce the associated risk," Miyashita said.