Postnatal depression linked to air pollution before and after childbirth
Postnatal – or postpartum – depression (PPD)is one of the most frequent complications associated with childbirth, affecting between 10% to 20% of women worldwide.
Mothers with PPD are vulnerable to suicide and may be more likely to commit infanticide, while infants born to mothers with PPD are thought to be at a higher risk of developing cognitive, emotional, and psychological impairments and behavioral abnormalities.
Because recent research has established a link between air pollution and mental health disorders among the general population, researchers in California set out to establish whether maternal ambient air pollution exposure could be associated with increased risks of postpartum depression.
This retrospective cohort study used health records of 340,679 women who gave birth in California between January 2008 and December 2016.
Participants who recorded an Edinburgh Postnatal Depression Scale score of 10 or higher during the six months after giving birth were referred to a clinical interview for further assessment and diagnosis.
From the original 340,679 participants, 25,674 were diagnosed with postpartum depression (7.54%).
Ambient air pollution exposures were assessed based on residential addresses using monthly averages of PM2.5, PM10, nitrogen dioxide and ozone. The constituents of PM2.5 were found to be sulfate, nitrate, ammonium, organic matter, and black carbon.
Increased risks for PPD were found to be associated with exposure to ozone and PM2.5 before and after birth. No prior research has explored the difference in concentrations and components of PM2.5. For trimester-specific exposures, the researchers found that first-trimester PM2.5 black carbon and second-trimester PM2.5 nitrate and ammonium exposures were associated with an increased risk of PPD.
For long-term exposures during pregnancy and postpartum periods, PM2.5 organic matter and black carbon were the main components associated with PPD.
The researchers conclude that these findings suggest that air pollution exposure is a potentially modifiable environmental risk factor for PPD and therefore an important public health issue to address for improved maternal mental health.
