Maternal exposure to ambient particulate matter (PM2·5) is associated with pregnancy loss (ie, stillbirth and miscarriage). South Asia has the highest burden of pregnancy loss globally and is one of the most PM2·5 polluted regions in the world.

Increasing evidence from epidemiological studies suggests that maternal exposure to ambient PM2·5 can increase the risk of pregnancy loss. However, no studies have been done in low-income countries such as those in Africa, which have the highest incidences of pregnancy loss.