Antepartum Environmental Exposures May Influence Neonatal Brain-Related Outcomes in Preterm Infants: JAMA
Canada: Researchers have found in a new cohort study that antepartum exposure to high ozone and to combined low temperatures with low greenness or high ozone levels was associated with lower odds of severe neonatal white matter microstructure modification (SWMM) in preterm infants. These findings suggest that maternal environmental exposures during pregnancy can have a significant impact on neonatal brain-related outcomes in preterm infants.
The study, published in JAMA Network Open, was led by Alice Aveline from the Neonatal Medicine Research Group at Imperial College London, along with collaborators in Canada. The investigators sought to determine whether maternal exposure to green spaces, air pollutants, and extreme temperatures during pregnancy was linked to outcomes among infants born at the limits of viability.
While environmental factors are known to contribute to the risk of preterm birth, less is understood about how these exposures affect neonatal outcomes after delivery. To address this gap, the researchers conducted a large population-based cohort study using linked data from the Canadian Neonatal Network and the Canadian Urban Environmental Health Research Consortium. The analysis included 14,748 infants born between 22 and 28 weeks' gestation, plus 6 days, from January 2010 to December 2020, all of whom received care in tertiary neonatal intensive care units across Canada.
Environmental exposure estimates were derived from maternal residential postal codes at the time of birth. The team generated indices representing levels of surrounding greenness, ambient air pollutants—including ozone—and temperature extremes during pregnancy. The primary outcome was survival without major morbidity (SWMM), assessed at either death or discharge from the NICU. Logistic regression models were applied to evaluate associations between individual and combined environmental exposures and the likelihood of SWMM.
The key findings were as follows:
- Of the infants included in the analysis, 54% were male, with a mean gestational age of 26.1 weeks and a median birth weight of 890 grams.
- Overall, 32.1% of infants survived without major morbidity (SWMM).
- Maternal exposure to higher ozone levels during pregnancy was associated with lower odds of SWMM compared with lower ozone exposure (adjusted odds ratio [AOR] 0.83).
- Combined exposure to low temperatures and high ozone levels was associated with reduced odds of SWMM (AOR 0.76).
- Exposure to low temperatures together with low greenness was also linked to lower odds of SWMM (AOR 0.77).
- The lowest odds of SWMM were observed with simultaneous exposure to low temperatures, low greenness, and high ozone (AOR 0.58).
The authors noted that it is concerning that, even in a high-income country such as Canada, measurable associations between environmental stressors and neonatal outcomes persist. They emphasized the need for further research in diverse populations and for studies exploring the long-term consequences of prenatal environmental exposures on growth, respiratory health, and neurodevelopment in childhood.
Reference:
Aveline A, Bando N, Noaeen M, et al. Antepartum Exposure to Greenness, Air Pollution, and Temperature and Outcomes of Preterm Infants. JAMA Netw Open. 2026;9(2):e260102. doi:10.1001/jamanetworkopen.2026.0102
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