Traffic fumes ‘are a threat to unborn babies’

UNBORN babies may be at risk of exposure to traffic pollution containing heavy metals, a study shows.

Analysis of the placentas of 15 new mothers in London found carbon particles that were thought to be from car exhausts.

The particles contained traces of iron, chromium and zinc that were similar in shape and size to those found in the airways of residents living on busy roads.

The placenta is linked to a baby in the womb, providing its nutrients and meaning some particles may have passed through.

The study’s authors say the particles may cause inflammation, potentially explaining why pregnant women exposed to higher levels of air pollution have a greater risk of their babies being born at a lower weight. Although more research is needed to prove such a link, the researchers think particles from wood-burning stoves and cooking may also reach the placenta.

Professor Jonathan Grigg, who led the study at Queen Mary University

of London, said: ‘These findings may help to explain the link between pollution and babies being born with a low birth weight.

‘Pollution affecting the placenta, and reaching the foetus that way, may have this effect, although more evidence is needed for this. We hope that this new information will encourage policymakers to reduce road traffic emissions in this post-lockdown period.’

The researchers, whose study is published in the journal Science of the Total Environment, recruited 15 healthy, non-smoking women who gave birth at the Royal London Hospital and analysed their placentas.

All the women had evidence of black carbon from air pollution within immune cells in their placentas, which the authors strongly linked to road traffic.

All but two lived in areas where levels of pollution were above the limit recommended by the World Health Organisation.

The black carbon appeared under a microscope, while the metals were found using a type of imaging called spectroscopy, based on the energy they release.

Marian Knight, professor of maternal and child population health at the University of Oxford, said: ‘Reassuringly for other pregnant women, all women whose placentas were examined for the purposes of the study gave birth to healthy babies at term and had no complications.’