Antepartum exposure to environmental stressors may affect health outcomes of preemies

Antepartum exposure to high ozone, low levels of greenness, and low temperatures appears to negatively influence the health outcomes of preterm infants, according to a study.

Researchers used linked national databases of the Canadian Neonatal Network and Canadian Urban Environmental Health Research Consortium. They identified infants born at 22–28 weeks plus 6 days of gestation over a period of 10 years.

The outcome of interest was infant survival without major morbidity (SWMM) assessed at death or discharge from the neonatal intensive care unit (NICU). Logistic regression models were used to assess this outcome in relation to indices summarizing levels of greenness, air pollutants, and ambient temperature at mothers’ residential postal code at birth.

A total of 14,748 infants (mean gestational age 26.1 weeks, 54 percent male, median birthweight 890) were included in the analysis. SWMM was documented in 32.1 percent of infants.

The odds of SWMM were 12-percent lower among infants born to mothers who were exposed to high ozone levels than among infants whose mothers were exposed to low ozone levels (adjusted odds ratio [AOR], 0.83, 95 percent confidence interval [CI], 0.74–0.95).

The likelihood of SWMM was also lower for infants born to mothers exposed to low temperature combined with either high levels of ozone (AOR, 0.76, 95 percent CI, 0.60–0.95) or low levels of greenness (AOR, 0.77, 95 percent CI, 0.60–0.99) or both low levels of greenness and high levels of ozone (AOR, 0.58, 95 percent CI, 0.43–0.77) when compared with infants whose mothers who were not exposed to these environmental factors.

Additional research is needed to evaluate the long-term implications of the observed association for childhood growth and respiratory and neurodevelopmental outcomes.