Exposure to air pollution during pregnancy leads to smaller babies, but living in a greener area helps

The European Respiratory Society International Congress, which opens in Milan tomorrow, will be told that women who are exposed to air pollution during pregnancy are more likely to give birth to smaller babies, but babies born to mums who live in greener are not as badly affected.

The study was based on data from the Respiratory Health in Northern Europe (RHINE) and presented by Mr Robin Mzati Sinsamala, from the Department of Global Public Health and Primary Care at the University of Bergen (UiB), Norway.

4,286 children and their mothers, living in five European countries (Denmark, Norway, Sweden, Iceland and Estonia) were studied, with the density of ‘greenness’ of the areas in which the women lived evaluated by satellite imagery. Greenery was taken to include forests, farmland and parks in urban areas.

The researchers also used data on five pollutants: nitrogen dioxide, ozone, black carbon, PM2.5 and PM10.

Researchers compared this information with the babies’ birthweights, taking account of other factors that may affect birthweight, such as mother’s age, smoker status and any other health conditions.

Even though the average levels of air pollution were within European Union standards, it was found that higher levels air pollution were linked with lower birthweights, with PM2.5, PM10, NO2 and BC associated with average reductions in birth weight of 56g, 46g, 48g and 48g, respectively.

When researchers took greenness into account, the effect of air pollution on birthweight was reduced. Women who lived in greener areas had babies with slightly higher birth weight (27g heavier on average) than mothers living in less green areas.

The research also identified a a link between birthweight and lung health, with low birthweight children facing a higher risk of asthma and higher rates of chronic obstructive pulmonary diseases (COPD) as they grow older.

Mr Sinsamala said: ‘The time when babies are growing in the womb is critical for lung development. We know that babies with lower birthweight are susceptible to chest infections, and this can lead on to problems like asthma and COPD later on.

‘Our results suggest that pregnant women exposed to air pollution, even at relatively low levels, give birth to smaller babies. They also suggest that living in a greener area could help counteract this effect. It could be that green areas tend to have lower traffic or that plants help to clear the air of pollution, or green areas may mean it’s easier for pregnant women to be physically active.’

The study is part of a programme of research called Life-GAP (Lifespan and inter-generational respiratory effects of exposures to greenness and air pollution) that is investigating the effects of air pollution and greenness on lung health in generations of Europeans over the long term.

European Respiratory Society Advocacy Council Chair, Professor Arzu Yorgancioğlu, who was not involved in the research, says: ‘This study adds to a growing body of evidence on the damage that air pollution is having on our health, especially in vulnerable babies and young children. Women who are pregnant will want to protect their babies from potential harm. However, as individuals, it can be difficult to reduce our exposure to air pollution or make our neighbourhoods greener.

‘As doctors and researchers who care about children’s health, we need to put pressure on governments and policy-makers to lower the levels of pollution in the air we breathe. This study also suggests that we could help to mitigate some of the effects of pollution by making our neighbourhoods greener.’