The impact of air pollution exposure on adverse pregnancy outcomes: a time-series study

This study aimed to explore the connections between six categories of atmospheric pollutants (PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃) and adverse pregnancy outcomes (low birth weight, LBW; preterm birth, PTB) in Hefei, China, using a combination of Distributed Lag Nonlinear Models and Generalized Additive Models to evaluate the nonlinear exposure-response associations and the lag effects of air pollutants on the risk of LBW and PTB. Stratified and sensitivity analyses were performed to examine the robustness of our findings. Among 44,727 live births from 2016 to 2020, 1,335 (2.98%) were identified as LBW, and 2,128 (4.76%) were classified as PTB. Among the six pollutants, exposure to PM₁₀ for pregnant women at lag0–11 weeks was observed to have the most significant impact on LBW, producing a relative risk (RR) of 1.100 (95% CI: 1.017, 1.189). In contrast, SO₂ exposure at lag0–5 weeks was most notably linked to the risk of PTB, with a RR of 1.559 (95% CI: 1.024, 2.374). Additionally, it was found that exposure to NO₂ and O₃ contributed to a heightened risk of adverse pregnancy outcomes. This study further substantiated the relationships between air pollution and the risk of LBW and PTB.