Maternal exposure to environmental stressors is associated with decreased odds of infant survival among preterm infants

1. In this cohort of very preterm infants, maternal exposure to low levels of greenness, high levels of ozone, and low temperatures was associated with decreased odds of infant survival without major morbidity (SWMM). 

Evidence Rating Level: 2 (Good) 

Exposure to modifiable environmental factors during pregnancy is linked to important perinatal and infant outcomes. Air pollution, extreme temperatures, and less access to green space increase the risk of stillbirth, low birth weight, and preterm birth, while also being associated with worse neonatal respiratory, infectious, and neurodevelopmental outcomes in term infants. Early preterm infants are at high risk for major complications; however, little is known about how antepartum environmental exposures affect outcomes. To address this gap, this retrospective cohort study aims to determine whether preterm infants born before 29 weeks have different neonatal outcomes based on their mothers’ exposure to air pollution, temperature extremes, and greenness during pregnancy. A total of 14,748 infants (mean [SD] gestational age, 26.1 [1.6] weeks) were included, with 6,845 (46.4%) born between 27 and 28 weeks of gestation, and 7,903 (53.6%) born before 27 weeks of gestation. Among the total population, 4,737 infants (32.1%) survived without major morbidity. High ozone levels were associated with decreased odds of infant survival without major morbidity (SWMM), with the highest vs. lowest tertile showing an adjusted odds ratio (AOR) of 0.83 (95% CI, 0.74-0.95; P=.007) and the moderate vs. lowest tertile having an AOR of 0.89 (95% CI, 0.82-0.97; P=.01). In contrast, temperature showed a weak relationship. The only significant difference was moderate vs. lowest temperature, with an AOR of 1.18 (95% CI, 1.07-1.31; P=.001). Low temperature combined with specific environmental conditions was associated with SWMM, including low temperature and low greenness (SWMM 29.1%; AOR 0.77, 95% CI 0.60-0.99; P=.04), low temperature and high ozone (SWMM 31.5%; AOR 0.76, 95% CI 0.60-0.95; P=.02), and the combination of low temperature, high ozone, and low greenness (SWMM 24.6%; AOR 0.58, 95% CI 0.43-0.77; P<.001). In summary, this cohort study found that antepartum exposure to certain environmental stressors is associated with poorer neonatal outcomes in very preterm infants. 

Click here to read this study in JAMA Network Open

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