The study provides further evidence supporting harmful effects of maternal PM2.5 exposure on birth outcomes and identifying critical windows. - GreenMedInfo Summary

BACKGROUND: Prenatal exposure to ambient levels of air pollution has been reported to adversely affect birth outcomes, yet few studies have investigated refined susceptible windows for adverse birth outcomes.

OBJECTIVES: The study aimed at estimating associations between maternal exposure to ambient fine particulate matter (PMparticles with an aerodynamic diameter ≤ 2.5 μm) and birth outcomes, including birth weight, low birth weight (LBW) and preterm birth (PTB), and identify specific susceptible windows.

METHODS: A total of 3692 singleton live births were enrolled between 2013 and 2016 in Shanghai Birth Cohort, China. Based on mothers' residential addresses, weekly mean concentrations of PMover gestation were estimated based on an incorporated evaluating approach combining satellite-based estimates and ground-level measurements. Distributed lag non-liner models (DLNMs) were fitted by incorporating with multiple liner models and Cox proportional hazard models to evaluate weekly-as well as trimester-exposure-lag-response associations between average PMlevel and birth weight, LBW and PTB, and to identify critical windows.

RESULTS: In this study, gestational exposure to PMwas associated with adverse birth outcomes in infants, and critical windows were identified as 31st-34th gestational weeks for reduced birth weight, 38th-42 nd weeks for LBW and 27th-30th weeks for PTB, respectively. Trimester-specific associations were found for all birth outcomes during the third trimester.

CONCLUSIONS: Ambient PMexposure exhibited adverse impacts on multiple outcomes including reduced birth weight, LBW and PTB in the late pregnancy. The study provides further evidence supporting harmful effects of maternal PMexposure on birth outcomes and identifying critical windows.