Air pollution linked to nearly 6 million premature births

SAN FRANCISCO, Calif. — Air pollution has a strong connection to a plethora of health problems including breathing problem, heart disease, and even depression. Now, researchers from the University of California-San Francisco and the University of Washington say smog likely contributed to nearly six million premature births worldwide and almost three million underweight babies in 2019 alone.

Notably, this research accounted for both outdoor and indoor air pollution. It’s the most comprehensive study to date investigating how smog influences pregnancy outcomes across a variety of factors including gestational age at birth, reduction in birth weight, low birth weight, and preterm birth. Moreover, it is the first study to account for indoor pollution on a global scale as well.

Wondering where indoor air pollution originates from? Study authors say cooking stoves account for two-thirds of indoor air pollution levels.

However, the notion of a connection between smog and premature birth and low birth weight isn’t entirely new. Preterm birth is the leading cause of neonatal mortality worldwide. Estimates show it affects roughly 15 million babies annually. Meanwhile, the World Health Organization states roughly 90 percent of the global population lives with some level of air pollution outside their doors. About half of the global population also deals with indoor air pollution originating from burning coal, dung, and wood inside homes.

Where is this problem the worst?

Premature birth or low birthweight is often more serious than it sounds. Many children born early or underweight deal with ongoing health problems for the remainder of their lives.

“The air pollution-attributable burden is enormous, yet with sufficient effort, it could be largely mitigated,” says lead study author Rakesh Ghosh, PhD, a prevention and public health specialist at the Institute for Global Health Sciences at UCSF, in a university release.

To reach these conclusions, the research team quantified preterm birth and low birthweight risks based on total indoor and outdoor pollution exposure. Additionally, they also accounted for the chance that negative effects taper off at higher smog levels.

Researchers note that air pollution is most prevalent in Southeast Asia and sub-Saharan Africa. It just so happens that preterm birth rates are also at their highest in those same areas. The study finds the global rate of preterm birth and low birthweight would drop by up to 78 percent if air pollution levels were lower in these regions.

American babies at risk as well

Make no mistake, though, air pollution is a global problem. In the United States, researchers say pollution contributed to nearly 12,000 preterm births in 2019 alone. A previous study put together by the same researchers also concluded that air pollution contributed to the deaths of 500,000 newborns globally in 2019.

“With this new, global and more rigorously generated evidence, air pollution should now be considered a major driver of infant morbidity and mortality, not just of chronic adult diseases,” Dr. Ghosh concludes. “Our study suggests that taking measures to mitigate climate change and reduce air pollution levels will have significant health co-benefit for newborns.”

The findings appear in the journal PLOS Medicine.