Previous exposure to air pollution increases the risk of severe respiratory problems in newborns, according to new research conducted at the Penn State College of Medicine in collaboration with the Health Canada-led Maternal-Infant Research on Environmental Chemicals (MIREC) Study. Risks increase, especially with fine particulate matter (PM2.5) and nitrogen dioxide (NO2), which originate from fires, cigarette smoke and vehicle emissions, among other sources.
The results, which were published in January. 25 in the journal Environmental Health Perspectives, published a better understanding of infant respiratory distress, a leading cause of neonatal intensive care unit admissions and death among newborns worldwide.
Maternal exposure to air pollution during pregnancy They are known to be associated with adverse long-term respiratory problems such as asthma in children. However, what we didn’t know is that maternal exposure to air pollution can cause babies to suffer from severe respiratory problems shortly after birth.”
Chintan K. Gandhi, assistant professor of pediatrics at Penn State and corresponding author of the paper
Researchers to conduct their research Data were analyzed from the MIREC Study, a multi-year study that examined the exposure of 2,001 pregnant women in 10 Canadian cities to environmental chemicals including PM2.5 and NO2. The MIREC study team estimated women’s exposure to PM2.5 and NO2 from three months before pregnancy through the end of the third trimester using models based on satellite data and ground-level air quality monitoring devices.
The MIREC team found that during the study period, women were exposed to PM2.5 concentrations ranging from 1.47 to 23.71 micrograms per cubic meter of air (μg/m3), with a median of 8.81 μg/m3, and NO2 concentrations from 1.72 to 53.10 parts per billion (ppb), with an average of 18.02 ppb. To provide context, the US Environmental Protection Agency provides values for maximum annual exposure of 9.0 to 10.0 µg/m3 for PM2.5 and 53 ppb for NO2.
However, Gandhi said, “There is actually no safe level of air pollution.”
Using data from the MIREC study, the team led by Penn State researchers examined the relationship between maternal air pollution exposure and physician-diagnosed respiratory distress in newborns. The test has expanded beyond diagnosis to include severity of respiratory distress as measured by the need for oxygen, mechanical ventilation, and systemic antibiotics in children.
“This sophisticated approach provides a comprehensive understanding of the complex relationship between maternal air pollution exposure and the varying degrees of respiratory distress observed in newborns,” Gandhi said.
Key findings of collaborative research include:
- Increased risk of severe respiratory distress: Babies born to mothers exposed to high levels of PM2.5 were more likely to experience severe respiratory distress, requiring interventions such as assisted ventilation and systemic antibiotics.
- Consistent association across stages of pregnancy: The association between PM2.5 exposure and severe respiratory distress was consistent whether exposure occurred earlier in pregnancy or at any stage of pregnancy.
- NO2 Exposure and Systemic Antibiotics: NO2 exposure in mothers was associated with an increased need for systemic antibiotics in children.
Gandhi made an important observation in the study, noting that the incidence of respiratory distress among children was consistent across different levels of air pollution exposure. However, a significant finding emerged in the increase in acute respiratory distress with increasing levels of exposure.
“We found that the more air pollution mothers are exposed to, the more likely their babies will suffer from severe respiratory problems,” he said.
Although the team did not investigate the specific mechanism by which pollutants are transferred from mother to child, Gandhi pointed to previous studies that indicated inflammatory markers in mothers exposed to air pollution. These markers, detected by blood tests in the same group of mothers, point to a possible pathway for the effects of air pollution on maternal health and its subsequent effects on newborns, he said.
“Our findings are of critical importance because they suggest that prevention of death and illness in children due to respiratory problems is plausible by reducing or eliminating air pollution,” Gandhi said. “It is imperative for policymakers to realize the gravity of this situation.”
Other authors of the paper include Markie Johnson, research scientist, Health Canada; Lauren Mazur, graduate student, Penn State; Mandy Fisher, Senior Epidemiologist, Health Canada; William Fraser, Professor, University of Sherbrooke; Liu Sun, Scientific Evaluator, Health Canada; and Perry Hystad, Associate Professor, Oregon State University.
The MIREC study was funded by Health Canada’s Chemical Management Plan, the Ontario Ministry of the Environment and the Canadian Institutes for Health Research.
Johnson, M., etc. (2024). Prenatal exposure to air pollution and respiratory distress in the neonatal period: results from the MIREC prospective pregnancy cohort. Environmental Health Perspectives. doi.org/10.1289/ehp12880.