Jun Wu
“This study adds important new data that helps us understand what environmental improvements can be made to help postpartum mothers adjust to their new lives after the birth of their child,” says senior and corresponding author Jun Wu, UCI professor of environmental and occupational health. Steve Zylius / UCI

Irvine, Calif., March 6, 2023 – In an analysis of more than 415,00 electronic health records of healthy, full-term births in Southern California, a team of researchers led by the University of California, Irvine determined that exposure to green space and tree coverage was associated with a decreased risk of postpartum depression among mothers.

The study, published online today in the journal The Lancet Regional Health – Americas, suggests that researchers, city planners and public health professionals should work together to develop policies and interventions that increase the amount of tree coverage to create a beneficial environment for community members – especially new mothers who are at risk of postpartum depression.

“This is the first study of its kind that examined the relationship between diverse green spaces, postpartum depression and the role of physical activity,” said senior and corresponding author Jun Wu, Ph.D., professor of environmental and occupational health in UCI’s Program in Public Health. “We were able to show a reduced risk of postpartum depression associated with eye-level exposure to green space on the streets of the neighborhood, and that reduction was further mediated by physical activity.”

According to the Centers for Disease Control and Prevention, 1 in 8 women who recently gave birth experience symptoms of postpartum depression, and if left untreated, the condition can impact the mother’s health and may cause sleeping, eating and behavioral problems for the baby.

The UCI team set out to fill a gap in research about the relationship between green space and postpartum depression. Existing studies only covered prenatal depression and relied solely on satellite-based green space data, without considering the types of green space or the mediating role of physical activity.

Analysis of the electronic health records of 415,020 singleton births to women residing in Southern California between 2008 and 2018 revealed that the highest reduction in risk of PPD was associated with a street-level view of green space, compared to, say, proximity to a park.

“The postpartum depression risk decreased by approximately 4.2 percent with each 10 percent increase in street-view green space,” said lead author Yi Sun, a former UCI postdoctoral scholar now a researcher at Peking Union Medical College. “Tree coverage showed stronger protective effects against postpartum depression versus other types of green space (i.e., low-lying vegetation and grass).”

Furthermore, the researchers found that increased physical activity during pregnancy was a plausible pathway linking green space to lower risk of postpartum depression.

The study was supported by the National Institute of Environmental Health Sciences under grant R01ES030353.

Darios Getahun, associate professor of health systems science at the Kaiser Permanente Bernard J. Tyson School of Medicine, was an equally contributing senior author. Other team members included John Molitor, associate professor of biostatistics at Oregon State University; Tarik Benmarhnia, associate professor of epidemiology at UC San Diego; Jiu-Chiuan Chen, associate professor of preventive medicine at USC; and lead senior research project manager Chantal Avila, biostatistician Vicki Chiu, associate investigator David A. Sacks and research scientist Jeff Slezak, all from Kaiser Permanente Southern California.

About UCI’s Brilliant Future campaign: Publicly launched on Oct. 4, 2019, the Brilliant Future campaign aims to raise awareness and support for UCI. By engaging 75,000 alumni and garnering $2 billion in philanthropic investment, UCI seeks to reach new heights of excellence in student success, health and wellness, research and more. The Program in Public Health plays a vital role in the success of the campaign. Learn more by visiting https://brilliantfuture.uci.edu/school-of-population-and-public-health.

About the University of California, Irvine: Founded in 1965, UCI is a member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced five Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 224 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UCI, visit www.uci.edu.

Media access: Radio programs/stations may, for a fee, use an on-campus ISDN line to interview UCI faculty and experts, subject to availability and university approval. For more UCI news, visit news.uci.edu. Additional resources for journalists may be found at communications.uci.edu/for-journalists.