Long-term Exposure to PM2.5 and Risk of Adverse Pregnancy Events in Women with Pulmonary Hypertension: A Nationwide Multicenter Study.
Abstract
Background
Fine particulate matter (PM2.5) has been linked with adverse pregnancy events. However, the effects of PM2.5 on pregnant women with pulmonary hypertension (PH) remain poorly understood.
Methods
We conducted a retrospective multicenter study of pregnant women with PH hospitalized at 24 tertiary hospitals in China between January 2016 and August 2022. Monthly PM2.5 exposure was estimated and the average PM2.5 concentrations during the 3-year exposure proceeding the end of pregnancy was used as the primary exposure metric. Generalized linear models with binomial distributions were applied to assess associations between PM2.5 exposure and adverse maternal events (maternal death and/or heart failure) and adverse fetal/neonatal events (non-live birth, neonatal death, preterm birth and low birth weight). Pregnancy-specific exposure windows and two-pollutant models were also examined.
Results
Among the 751 participants, 198 (26.4%) experienced adverse maternal events, and 449 (59.8%) had adverse fetal/neonatal events. Three-year median PM2.5 concentration before the end of pregnancy was 32.8 (26.2-44.0) μg/m³. In the fully adjusted model, each 10 μg/m3 increase in PM2.5, the odds ratio (OR) was 1.169 (95% CI: 1.014-1.349) for the adverse maternal events and 1.169 (95% CI: 1.018-1.348) for adverse fetal/neonatal events. These associations remained robust in two-pollutant models. Furthermore, when exposure assessment was shifted from long-term levels to pregnancy-specific windows, the strongest trimester-specific association was observed during late pregnancy.
Conclusions
Long-term PM2.5 exposure was associated with increased risk of adverse pregnancy events among pregnant women with PH, emphasizing the importance of reducing air pollution exposure in this high-risk population.