The association between air pollutant exposures and hyperemesis Gravidarum

This study investigated the association between exposure to ambient air pollutants and hyperemesis gravidarum (HG) and identified potential sensitive exposure windows. We conducted a population-based cohort study of 3703,252 pregnant women in Shandong Province (2016-2022) using the Extended Cheeloo Lifespan Electronic Health Research Database. HG was classified using hospital admissions and outpatient department visits during pregnancy. Individual-level exposure to air pollutants was estimated by linking satellite-derived spatial data to residential addresses. Average exposures were calculated for five windows: one long-term period covering gestation until the health visit (Pre_V) and four acute-phase periods (1-14 days pre-visit; Pre01-Pre014). Firth's penalized logistic regression and weighted quantile regression(WQS) were utilized to analyze the associations. Overall, 1.14% (n = 42,105) of the cohort experienced HG. Significant positive associations were observed between HG and exposure to PM_2.5, NO₂, CO and SO₂. In the Pre_V windows, the odds ratios per IQR increase were 1.534 (95% CI: 1.486, 1.583) for PM_2.5, 1.436 (95% CI: 1.406, 1.466) for NO₂, 1.873 (95% CI: 1.822, 1.926) for SO₂, and 1.629 (95% CI: 1.581, 1.678) for CO. The WQS analysis confirmed a significant positive association between the pollutant mixture and the odds of HG for all exposure periods, with SO₂ identified as the primary contributor to the overall mixture effect. Stratified analyses revealed that younger pregnant women exhibited heightened susceptibility to the adverse effects of air pollution on HG. These findings emphasize the importance of minimizing air pollution exposure during pregnancy to reduce the risk of HG and related adverse pregnancy outcomes.