Meeting India’s air quality targets across south Asia may prevent 7 per cent of pregnancy losses in the region,  according to a study published in the Lancet journal.

The modelling study suggested that pregnant women in India, Pakistan, Bangladesh, who are exposed to poor air quality, may be at higher risk of stillbirths and miscarriages. It said that an estimated 349,681 pregnancy losses per year in south Asia were associated with exposure to PM2.5 concentrations that exceeded India’s air quality standard (more than 40 ig/m or micrograms per cubic meter air), accounting for 7 per cent of annual pregnancy loss in the region from 2000-2016.

In the study, the researchers included 34,197 women who had lost a pregnancy, including 27,480 miscarriages and 6,717 stillbirths, which were compared to livebirth controls.

Of the pregnancy loss cases, 77 per cent were from India, 12 per cent from Pakistan, and 11 per cent from Bangladesh.

Pregnancy loss associated with air pollution was more common in the northern plains region in India and Pakistan.

Previous studies have suggested a link between air pollution and pregnancy loss in other regions, but this is the first study, published in Lancet Planetary Health, to quantify the burden in south Asia.

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,” said lead study author Dr Tao Xue from Peking University in China.

To carry out their analysis, the authors combined data from household surveys on health from 1998-2016 (from women who reported at least one pregnancy loss and one or more livebirths) and estimated exposure to PM2.5 during pregnancy through combining satellite with atmospheric modelling outputs.

The researchers, however noted several limitations of their study. In the surveys, they were not able to distinguish between natural pregnancy loss and abortions and there was under-reporting of pregnancy losses because of stigma or ignoring very early pregnancy losses.