Joint associations between maternal exposure to ambient air pollutants during pregnancy and low Apgar score in newborns: a birth cohort study in China

Epidemiological evidence on the risk of low Apgar score in newborns associated with ambient air pollutants, their joint associations, and sensitive exposure windows is limited. This study aimed to investigate the independent and joint associations between exposure to ambient air pollutants during different pregnancy trimesters and low Apgar score in newborns. Twenty thousand eight hundred ninety-four pregnant women were included in the prospective birth cohort in Shenzhen. Concentrations of PM 2.5 , PM 10 , NO 2 , O 3 , SO 2 , and CO were assessed based on residential addresses of participants. Generalized additive model (GAM) was used to assess the independent associations of air pollutants exposure with low Apgar score, and restricted cubic spline (RCS) model was used to analyze the dose-response trends. Quantile g-computation (Qgcomp) and weighted quantile sum (WQS) regression models were further used to investigate the joint associations and constituent contributions. Second-trimester exposure to PM 2.5 , PM 10 , and NO 2 was associated with an increased risk of low 1-minute Apgar score (PM 2.5 : OR = 1.64, 95% CI: 1.10, 2.44; PM 10 : OR = 1.59, 95% CI: 1.01, 2.50; NO 2 : OR = 1.48, 95% CI: 1.11, 1.98, per interquartile range increase). In the mixed-pollutant models, both Qgcomp and WQS models showed that each one-quartile increase in the air pollutant mixture was significantly associated with low 1-minute Apgar score (Qgcomp: OR = 1.48, 95% CI: 1.06, 2.07; WQS: OR = 1.15, 95% CI: 1.09, 1.21). PM 2.5 and NO 2 were the primary contributors to the risk (Qgcomp: 48.0%, 34.5%; WQS: 23.6%, 39.4%). Second-trimester exposure to air pollutants was associated with an increased risk of low 1-minute Apgar score, and PM 2.5 and NO 2 may be the key relative contributors. These findings support the need for further research and increased public health attention to air pollutant exposure during pregnancy to prevent adverse neonatal health outcomes. Not applicable.