Associations of maternal exposure to fine particulate matter constituents during pregnancy with Apgar score and duration of labor: A retrospective study in Guangzhou, China, 2012–2017

Limited evidence is available for demonstrating effects of prenatal PM2.5 and its components exposure on Apgar score and duration of labor. We sought to investigate the associations between PM2.5 constituents, Apgar score and duration of labor, and evaluated the potential mediating role of duration of labor. This study included 5396 participants. The V4·CH.02 was applied to assessing exposure to PM2.5 constituents. The associations between PM2.5 constituents Apgar score and duration of labor were examined by multivariate linear regression. Mediation analysis was conducted to estimate the potential mediation effect of duration of labor. Trimester-specific exposure to soil dust was significantly associated with 1-min Apgar score (1st trimester: OR: 1.03, 95% CI:0.97, 1.10; 2nd trimester: OR: 1.07, 95% CI: 1.01, 1.14; 3rd trimester: OR: 1.07, 95% CI: 1.01, 1.13), duration of first stage of labor (1st trimester: β: 0.32, 95% CI: 0.07, 0.58; 2nd trimester: β: 0.27, 95% CI: 0.04, 0.51; 3rd trimester: β: 0.37, 95% CI: 0.13, 0.61) and duration of second stage of labor (1st trimester: β: 0.04, 95% CI: −0.00, 0.09; 2nd trimester: β: 0.05, 95% CI: 0.01, 0.10; 3rd trimester: β: 0.05, 95% CI: 0.00, 0.09). The duration of labor mediated the relationship between soil dust and 1-min Apgar score. This study demonstrated that prenatal exposure to soil dust was significantly associated with the risk of abnormal 1-min Apgar score and extended stage of labor.