Systemic Oxidative Stress Levels During the Course of Pregnancy: Associations with Exposure to Air Pollutants

Abstract

Background: Increased systemic oxidative stress, implicated in adverse pregnancy outcomes for both mothers and fetuses, has been associated with gestational exposure to air pollutants such as polycyclic aromatic hydrocarbons (PAHs), fine particulate matter (PM2.5), and nitrogen dioxide (NO2). However, it is unclear whether exposure to pollutants at levels below the current air quality standards can increase oxidative stress in pregnant women.

Methods: In a cohort of 305 pregnant persons residing in western New York, we examined the association between exposure to PM2.5, NO2, and PAHs (measured as urinary 1-hydroxypyrene) and urinary biomarkers of oxidative stress (malondialdehyde [MDA] and 8-hydroxy-2'-deoxyguanosine  [8-OHdG]) measured in each trimester.

Results: After controlling for gestational stage, maternal age, lifestyles, and socioeconomic factors, each interquartile range (IQR) increase in 1-hydroxypyrene concentration (65.82 pg/ml) was associated with a 7.73% (95%CI: 3.18%,12.29%) higher in MDA levels throughout the pregnancy and in each trimester. An IQR increase in PM2.5 concentration (3.20 μg/m3) was associated with increased MDA levels in the first trimester (8.19%, 95%CI: 0.28%,16.10%), but not the 2nd(-7.99%, 95% CI: -13.80%, -2.23%) or 3rd trimester (-2.81%, 95% CI: -10.00%, 4.38%). The average cumulative PM2.5 exposures in the 3-7 days prior to urine collection were associated with increased 8-OHdG levels during the second trimester, with the largest difference (22.59%; 95% CI: 3.46%, 41.72%) observed in relation to an one IQR increase in PM2.5 concentration in the previous 7 days. In contrast, neither oxidative stress biomarker was associated with NO2 exposure.

Conclusions: Observed in pregnant women exposed to low-level air pollution, these  findings expanded previously reported associations between systemic oxidative stress and high-level PM2.5 and PAHs concentrations. Further, the first and second trimester may be a susceptible window during pregnancy for oxidative stress responses to air pollution exposure.

Note:

Funding Information: This study is funded by the National Institutes of Health (R01ES027495, UG3 OD023349, R01HD083369) and The Wynne Center for Family Research. The project described in this publication received support from the University of Rochester Clinical and Translational Science Award (CTSA) with award number UL1 TR002001 from the National Center for Advancing Translational Sciences of the National Institutes of Health, as well as the Rutgers and URMC P30 centers: P30ES005022, P30ES001247.

Conflict of Interests: The authors declare no competing interests.

Ethical Approval: The study was approved by the University of Rochester Research Subjects Review Board (#58456) and the Institutional Review Board of Duke University (2018-0181). All participants provided written informed consent.

Keywords: Oxidative stress, Pregnancy, PAHs, PM2.5, Trimester, Low-level exposure