Prenatal fine particulate matter raises odds for severe respiratory distress in newborns
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Key takeaways:
- As prenatal PM2.5 exposure rose, so did the odds for assisted ventilation, multiple interventions and systemic antibiotics.
- High prenatal nitrogen dioxide exposure also raised the odds for systemic antibiotics.
Elevated exposure to fine particulate matter during pregnancy raised the likelihood for assisted ventilation and systemic antibiotics among term newborns, according to results published in Environmental Health Perspectives.
“The findings of this study have significant implications for everyday clinicians, as they shed light on the critical role of prenatal air pollution exposure in influencing neonatal respiratory outcomes,” Chintan K. Gandhi, MBBS, assistant professor of pediatrics at Penn State University, told Healio.
“Clinicians should be aware that even in areas with seemingly low ambient concentrations, exposure to fine particulate matter (PM2.5) during pregnancy is strongly associated with severe respiratory distress in term newborns,” Gandi continued. “This includes a higher likelihood of requiring assisted ventilation, multiple clinical interventions and systemic antibiotics.”
Using the cohort from the Maternal-Infant Research on Environmental Chemicals Study, Gandhi and colleagues assessed how prenatal exposures to PM2.5 (n = 1,321; 41.9% aged 35 years or older; 85.9% white) and nitrogen dioxide (n = 1,064; 43.6% aged 35 years or older; 83.5% white) impact physician-diagnosed respiratory distress and the severity of respiratory distress in term newborns.
To find estimated levels of exposure to these pollutants, researchers collected every mother’s home address and used land-use regression and satellite-derived models, as well as ground-level monitoring.
Characteristics
Respiratory distress was reported in 7.3% of infants in the PM2.5 analysis and 8.2% of infants in the nitrogen dioxide analysis.
In both the PM2.5 analysis and the nitrogen dioxide analysis, researchers found a similar proportion of infants given oxygen therapy (5.8%; 6.1%), placed on assisted ventilation (1.7%; 2.1%), given systemic antibiotics (2.6%; 3%), admitted to the NICU (3.8%; 3.5%) and receiving multiple (two or more) clinical interventions (1.9%; 2.3%).
In terms of prenatal air pollution exposure, the median concentration of PM2.5 was 8.81 µg/m3, whereas the median concentration of nitrogen dioxide was 18.02 ppb.
Results
Using hierarchical logistic regression models that accounted for detailed maternal and infant covariates, researchers did not find a significant link between prenatal pollutant exposure and respiratory distress.
Despite this result, prenatal PM2.5 exposure did impact the severity of respiratory distress. According to researchers, every 1 µg/m3 rise in PM2.5 significantly increased the likelihood for assisted ventilation use (adjusted OR = 1.17; 95% CI, 1.02-1.35), multiple interventions (aOR = 1.16; 95% CI, 1.07-1.26) and systemic antibiotic administration (aOR = 1.12; 95% CI, 1.04-1.21).
Researchers additionally noted consistency of these results in analyses that looked at exposure before pregnancy, during individual trimesters and total pregnancy.
Similar to PM2.5, the odds for systemic antibiotic administration went up with each 1 ppb rise in prenatal nitrogen dioxide (OR = 1.03; 95% CI, 1-1.06).
Notably, there was no link between prenatal exposure to PM2.5 and an increased likelihood for oxygen therapy or NICU admittance, and the same was true for prenatal exposure to nitrogen dioxide.
Researchers reported similar overall findings in a sensitivity analysis that only included women with data on both pollutants (n = 1,020).
“Understanding these associations allows clinicians to consider environmental factors during prenatal care, emphasizing the importance of minimizing exposure to air pollution for expectant mothers,” Gandhi told Healio.
Taking into consideration the findings from this study, Gandhi said it is evident that there is a need for tailored interventions and increased awareness among health care providers.
“Ultimately, incorporating this information into clinical practice can contribute to more informed decision-making and improved outcomes for both mothers and their newborns,” he told Healio.
Future research
Moving forward, Gandhi told Healio that future studies will need to address several knowledge gaps, one being the mechanisms behind the observed associations.
“[Future research may investigate] the specific mechanisms through which pollutants are transmitted from mother to child,” Gandhi said. “Understanding the biological pathways involved can provide more targeted interventions and preventive strategies.”
Another unclear area in this research is whether there are periods during pregnancy that change the impact prenatal pollutant exposure has on the newborn.
“This information can guide interventions aimed at specific stages of pregnancy,” Gandhi said.
Researchers should also investigate how social determinants of health and different sources of air pollution (indoor vs. outdoor) alter the associations found in this study, Gandhi said.
Lastly, Gandhi suggested conducting intervention studies that evaluate the effectiveness of interventions aimed at reduced or eliminating air pollution when a woman is pregnant.
“This could involve community-based initiatives, policy changes or targeted interventions for high-risk populations,” Gandhi said.
Reference:
- Prenatal air pollution exposure linked to severe newborn respiratory distress. https://www.psu.edu/news/research/story/prenatal-air-pollution-exposure-linked-severe-newborn-respiratory-distress/. Published Jan. 30, 2024. Accessed Jan. 30, 2024.
Perspective
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This study by Johnson, et al is significant because it investigates the association between the leading cause of neonatal morbidity and mortality, respiratory distress, and two ubiquitous air pollutants, PM2.5 and nitrogen dioxide.
These and other air pollutants are already known to be strongly correlated with adverse birth outcomes that raise the risk for lifelong health harms, but the possibility of immediate post-delivery complications has not been well-studied.
Although novel, the finding of a strong association between PM2.5 exposure and severe respiratory distress in term newborns is not surprising given prior research findings and the multiplicity of potential mechanisms impairing both healthy in-utero lung development and immune system function. It is worth emphasizing that these outcomes were found in Canadian cities with relatively low levels of PM2.5; many large urban centers around the world have levels four to even 10 times higher.
The study results are strengthened by the author’s diligent efforts to avoid exposure misclassification. Future research, in addition to examining high-risk sub-populations and shorter pregnancy intervals (low birth weight or premature infants, non-white subjects, specific gestational weeks) could investigate the possible influence of seasonality, ie, heat’s effect on ozone levels. As technology evolves, wearable exposure monitors will improve the accuracy of findings and help clarify the impact of exposure reduction strategies.
The key takeaway from this study is that it adds to the growing evidence linking serious adverse birth outcomes and air pollution — a modifiable risk factor. The need to rapidly transition to clean energy to stabilize our climate is even more urgent given the necessity of protecting this and future generations from devastating injury. Clinicians can and should play a role in educating patients and impressing upon elected officials the need for immediate action.
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