Long-Term Exposure to Air Pollution May Raise Risk for Postpartum Depression

Long-term antepartum and postpartum exposure to ozone and particulate matter have been found to increase the risk for postpartum depression (PPD) among pregnant women living in Southern California.

The international research team, which included health care professionals from the University of California, Irvine (UCI); Kaiser Permanente Southern California (KPSC); the University of Southern California; Oregon State University; and the Scripps Institution of Oceanography, published study findings in JAMA Network Open.

“Postpartum depression is a major public health problem,” said corresponding author Jun Wu, PhD, professor of environmental and occupational health, UCI, in a press release. “Due to increased susceptibility of mothers during the antepartum and postpartum periods, identifying modifiable environmental risk factors is important, as it can support future intervention studies on reducing the rate of PPD.”

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To conduct the retrospective cohort study, researchers utilized data from KPSC electronic health records and included women who had singleton live births at KPSC facilities between January 1, 2008, and December 31, 2016. The research team assessed ambient air pollution exposures based on maternal residential addresses and established monthly averages of particulate matter less than or equal to 2.5𝝻m (PM_2.5), particulate matter less than or equal to 10𝝻m (PM₁₀), nitrogen dioxide (NO₂), and ozone (O₃), and “constituents” of PM_2.5, including sulfate, nitrate, ammonium, organic matter, and black carbon. Participants exhibiting a score of 10 or higher on the Edinburgh Postnatal Depression scale during the 6 months following birth were referred to a clinical interview for further assessment and diagnosis.

The study ultimately included 340,679 participants (mean [SD] age, 30.05 [5.81] years), with 25,674 experiencing PPD (7.54%). Increased risks for PPD were associated with increased in antepartum and postpartum exposures to O₃ (adjusted odds ratio [AOR], 1.09; 95% CI, 1.06-1.12), PM₁₀ (AOR, 1.02; 95% CI, 1.00-1.04, and PM_2.5 (AOR, 1.02; 95% CI, 1.00-1.03), but not with NO₂. “Overall, a higher risk of PPD was associated with O3 during the entire pregnancy and postpartum periods and with PM exposure during the late pregnancy and postpartum periods,” the authors wrote.

The researchers also found that certain demographics were more vulnerable to pollutant exposure and PPD risk, including mothers aged 25 to 34, Black or Hispanic women, those with higher education, and those who were underweight.

“We want to raise awareness of the significant impact that [air pollution] has on pregnant women, new moms and their families, and we’ll conduct further research to explore the joint effects of multiple stressors, including social factors such as race and socioeconomic status and environmental factors such as air pollution, noise and lack of green space,” said first author Yi Sun, PhD, previously a UCI postdoctoral researcher and currently a researcher at the Chinese Academy of Medical Sciences’ Institute of Medical Information. “With more evidence from future studies, we hope to identify modifiable environmental risk factors to support interventions, such as the use of air filters or masks for the most vulnerable groups of pregnant and postpartum women.”

References

Sun Y, Headon KS, Jiao A, et al. Association of antepartum and postpartum air pollution exposure with postpartum depression in Southern California. JAMA Netw. Open. 2023;6(10):e2338315. doi:10.1001/jamanetworkopen.2023.38315

UC Irvine-led study links long-term air pollution exposure to postpartum depression in SoCal. News release. University of California, Irvine. Published online October 31, 2023. Accessed November 15, 2023.