Maternal Exposure to Ambient Air Pollution and Pregnancy Complications in Victoria, Australia

• Main Authors: Shannon M. Melody, Karen Wills, Luke D. Knibbs, Jane Ford, Alison Venn, Fay Johnston
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: air pollution; pregnancy; gestational diabetes mellitus; preeclampsia; placental abruption
• Online Access: https://www.mdpi.com/1660-4601/17/7/2572

The relationship between maternal exposure to ambient air pollution and pregnancy complications is not well characterized. We aimed to explore the relationship between maternal exposure to ambient nitrogen dioxide (NO₂) and fine particulate matter (PM_2.5) and hypertensive disorders of pregnancy, gestational diabetes mellitus (GDM) and placental abruption. Using administrative data, we defined a state-wide cohort of singleton pregnancies born between 1 March 2012 and 31 December 2015 in Victoria, Australia. Annual average NO₂ and PM_2.5 was assigned to maternal residence at the time of birth. 285,594 singleton pregnancies were included. An IQR increase in NO₂ (3.9 ppb) was associated with reduced likelihood of hypertensive disorders of pregnancy (RR 0.89; 95%CI 0.86, 0.91), GDM (RR 0.92; 95%CI 0.90, 0.94) and placental abruption (RR 0.81; 95%CI 0.69, 0.95). Mixed observations and smaller effect sizes were observed for IQR increases in PM_2.5 (1.3 µg/m³) and pregnancy complications; reduced likelihood of hypertensive disorders of pregnancy (RR 0.95; 95%CI 0.93, 0.97), increased likelihood of GDM (RR 1.02; 95%CI 1.00, 1.03) and no relationship for placental abruption. In this exploratory study using an annual metric of exposure, findings were largely inconsistent with a priori expectations and further research involving temporally resolved exposure estimates are required.