A novel global study has attributed approximately a million stillbirths a year in Asia, Africa, and Latin America to air pollution.
The first-of-its-kind study was published in Nature Communications at the end of November, the work of a team of scientists led by Dr. Tao Xue at Peking University in China.
The study examined stillbirths in 137 countries in Asia, Africa, and Latin America, where 98% of stillbirths occur, by tracking pregnancy outcomes and air pollution as measured in ambient fine particulates from 1998-2016. The researchers concluded that almost half of stillbirths could be linked to exposure to pollution particles smaller than 2.5 microns (PM2.5).
“We found a robust association between PM2.5 levels and stillbirths,” the study reads. “According to the fully adjusted model, each 10 μg/m3 increment in PM2.5 was associated with a 11.0% (95% CI: 6.4, 15.7) increased risk of stillbirth.”
The World Health Organization considers air pollution concentrations above 5 micrograms per cubic metre harmful to human health, and almost all of the women examined in the study had been exposed to levels of air pollution above that. It attributed 45% of the 2.09 million stillbirths recorded in 2015 in the countries included in the study to exposure to high concentrations of air pollution and particulate levels above the WHO recommendations. Nigeria, Pakistan, and China had a particularly high proportion of stillbirths attributed to PM2.5 pollution, according to the study.
This research comes on the heels of a study published in October that found toxic ambient particulates in the lungs and brains of foetuses. Air pollution particles have already been associated with increased miscarriages, premature births, low birth weights, and disturbed brain development.
Professor Gregory Wellenius, the director of the Center for Climate and Health at Boston University in the U.S., who was not involved in the research, told the Guardian: “This study is novel and demonstrates that at current levels, air pollution contributes to a substantial number of stillbirths around the world:”
Health impact assessments such as this are always based on a number of important assumptions. Although the fraction of stillbirths that might be prevented through meaningful reductions in PM2.5 is uncertain, the study adds to the abundance of scientific evidence showing that reducing air pollution levels would improve the health of people around the world, particularly among the most vulnerable individuals.
Fortunately, the total number of stillbirths fell from 2.31 million in 2010 to 1.93 million in 2019, a consequence, according to the researchers, of improved air quality in some of the countries included in the study.