Air pollution exposure in the womb linked to negative impacts on stress responses of newborn babies

The study measured exposure to tiny particles and nitrogen dioxide, common in fires and vehicle emissions

Exposure to air pollution in the womb has been linked to negative impacts on the cells of newborn babies including in their stress responses.

A study, published on Tuesday, adds to mounting evidence that air pollution has significant impacts on children, even before they arrive in the world.

Air pollution has been top of mind in many parts of the world this summer as out-of-control wildfires raged from Canada, the US West, and Hawaii to North Africa, Greece and Spain.

Fires spew vast amounts of pollutants into the atmosphere, often a complex mix of harmful substances from whatever the fire has devoured in its path.

That mix often contains tiny particles, like PM10, and gases such as nitrogen dioxide (NO2), which this new study examined. (Vehicle emissions is another major source of these pollutants.)

The study was led by Dr Olga Gorlanova, a research physician at University Children’s Hospital in Basel, Switzerland, who found that a mother’s exposure to air pollution during pregnancy can affect the baby’s autophagy - the body’s cellular recycling system which sees the “self-eating” of damaged cells in response to stress. Air pollution also had an impact on processes related to ageing and cell remodelling.

Dr Gorlanova’s work previously discovered that exposure to air pollution during pregnancy could affect lung function and immune system in newborns.

The team measured the mothers’ exposure to NO2 and PM10, and then tested 11 proteins found in the cord blood of 449 healthy newborns. Researchers found that NO2 and PM10 were both linked to changes.

“Our results indicate that NO2, a pollutant formed mainly from traffic emissions, is associated with increased levels of Beclin-1 protein, which is central to initiating autophagy,” said Dr Gorlanova.

“Exposure to higher NO2 was also linked to decreased levels of SIRT1, which is a protein that plays a protective role in stress resistance, inflammation and aging. IL-8 is a protein active in certain inflammatory cells.”

However,the newborns had individual and different responses to their mothers’ air pollution exposure during pregnancy, a possible indication that some were more vulnerable than others. This was the case even if the family lived in an area with relatively low levels of pollution.

The next step is to see whether the babies impacted by air pollution suffer more breathing problems as they grow up compared to those whose proteins were unaffected.

Professor Marielle Pijnenburg, head of the Department of Pediatric Respiratory Medicine and Allergology at Erasmus Medical Center in the Netherlands, who was not involved in the study, said the research sent a message “loud and clear” on air pollution threats.

“We should all be re-doubling our efforts to reduce air pollution as quickly and as far as possible. This will not only improve the health of populations and reduce costs associated with treating diseases caused by air pollution, but will also help the environment at a time when the climate emergency is becoming more and more apparent as every day passes,” she said.

Air pollution is the greatest external threat to life expectancy, according to an update in August from the Air Quality Life Index, a sweeping international research project.

Stanford economist Marshall Burke also recently noted in a tweet that the average American had been exposed to 450 micrograms of smoke per cubic meter by early July 2023 - worse that the entirety of the years from 2006-2022.