Associations between maternal exposure to air pollution during pregnancy and trajectories of infant growth: A birth cohort study.

ABSTRACT

OBJECTIVE: We examined the relationships between infants' growth trajectories and prenatal exposure to air pollution, which is still under-investigated. METHODS: A birth cohort study was constructed using medical records of pregnant women and infants born between 2015 and 2019 in Foshan, China. Using satellite-based spatial-temporal models, prenatal exposure to air pollutants including particulate matter with an aerodynamic dimension of < 2.5 µm (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3) was assessed at each woman's residence. Latent class growth modeling was used to identify trajectories of physical (body length and weight) growth and neurodevelopment, which were repeatedly measured within 1 year after birth. Logistic regression models were used to investigate the associations between prenatal exposure to air pollution and the risks of growth disorders, adjusting for an array of potential confounders. RESULTS: We identified two growth trajectories for body length [normal 3829 (93%); retardation 288 (7%)], three for weight [normal 2475 (59.6%); retardation 390 (9.4%); overgrowth 1287 (31%)], and two for neurodevelopment [normal 956 (66.1%); retardation 491 (33.9%)]. For exposure over whole pregnancy, SO2 was associated with an increased risk of body length retardation (OR for per 1 µg/m3 increment 1.09, 95%CI 1.01-1.17); PM2.5 (OR 1.05, 95%CI 1.03-1.07), SO2 (OR 1.15, 95%CI 1.08-1.22), and NO2 (OR 1.05, 95%CI 1.03-1.07) were positively associated with neurodevelopmental retardation. Such associations appeared stronger for exposures over the first and second trimesters. No significant associations were detected for weight growth. CONCLUSIONS: Maternal exposure to air pollution during pregnancy was associated with higher risks of impairments in both physical growth, particularly body length, and neurodevelopment.