Prenatal Exposure to Air Pollution and Respiratory Distress in Term Newborns: Results from the MIREC Prospective Pregnancy Cohort.

Johnson M, Mazur L, Fisher M, Fraser WD, Sun L, Hystad P, Gandhi CK. Environmental Health Perspectives 2024 Jan;132(1):17007. doi: 10.1289/EHP12880. Epub 2024 Jan 25

Question: What is the relationship between air pollution exposure and respiratory distress in full-term neonates?

Respiratory distress in newborns can lead to infant health problems. Exposure to air pollution in pregnancy has been associated with respiratory symptoms in mothers, but the effect on newborns has rarely been looked at.

What did the researchers do:
Researchers from Health Canada estimated levels of both fine particular matter (PM2.5) and nitrogen dioxide (NO2) for each woman in the study during pregnancy, based on national air quality models and data measured at air pollution monitoring stations across Canada. Information on whether the newborn experienced respiratory distress at birth was collected from the newborn medical chart.

What did they find:
The researchers found that less than 10% of the MIREC newborns experienced respiratory distress according to chart reviews. Prenatal exposures to air pollution were not associated with physician-diagnosed respiratory distress, oxygen therapy, or NICU (neonatal intensive care unit) admissions. However, PM2.5 exposures were associated with indicators of severe respiratory distress in newborns, including use of assisted ventilation, and having multiple clinical interventions, as well as receiving systemic antibiotics. Associations between PM2.5 exposure and severe respiratory distress were seen consistently across different exposure periods, including exposures prior to pregnancy, during each trimester, and across the entire pregnancy. NO2 exposure was associated with a slightly higher chance of receiving systemic antibiotics.

What does this mean:
This research found an association between higher prenatal exposures to PM2.5 and increased risk of severe respiratory distress among newborns born at term. These findings support the development and prioritization of public health and prenatal care strategies to increase awareness and minimize prenatal exposures to air pollution.

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