Air pollution is associated with increased risk of pregnancy loss

Gestational exposure to particulate matter (PM2.5) pollution is associated with an increased likelihood of pregnancy loss in south Asia, according to a study published in The Lancet Planetary Health. 

Various previous studies have suggested that there might be a link between air pollution and pregnancy loss, but this is the first study to look specifically at the burden in south Asia, the most populous region in the world and the one with the highest rate of pregnancy loss. 

In order to investigate the link, the researchers combined data from household surveys from women who reported at least one pregnancy loss and one or more live births, and then they estimated their exposure to particulate matter (PM2.5) during their pregnancy. 

The researchers then created a model which allowed them to examine how exposure to PM2.5 increased the women’s risk of pregnancy loss.

After adjusting for factors such as maternal age, temperature and humidity, seasonal variation, and long-term trends, the researchers found that gestational exposure to PM2.5 was associated with an increased likelihood of pregnancy loss, and this remained significant after adjusting for other factors.

They found that each increase of 10 μg/m³ was estimated to increase a mother’s risk of pregnancy loss by 3%.

The increase in risk was greater for mothers from rural areas or those who became pregnant at an older age.

From 2000 to 2016, 349,681 pregnancy losses per year were associated with ambient exposure to air pollution – accounting for 7% of the total annual pregnancy loss burden in this region.

For air pollution above the World Health Organisation air quality guideline, exposure may have contributed to 29% of pregnancy losses. 

Lead author on the study, Dr Tao Xue, from Peking University, China, said: ‘South Asia has the highest burden of pregnancy loss globally and is one of the most PM2.5 polluted regions in the world.

‘Our findings suggest that poor air quality could be responsible for a considerable burden of pregnancy loss in the region, providing further justification for urgent action to tackle dangerous levels of pollution.’

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