PM2.5 Exposure and Depression in Pregnant Women: A Systematic Review and Meta-Analysis

<ns3:p>Exposure to particulate matter (PM2.5) has emerged as a significant risk factor for depression, particularly among pregnant women. This systematic review and meta-analysis investigate the association between PM2.5 exposure and maternal depression during pregnancy. Adhering to PECO principles and PRISMA 2020 standards, we searched PubMed, Google Scholar, and Science Open, identifying 231 records (Google Scholar: 28; Science Open: 106; PubMed: 58; and 39 from manual searches). After removing 49 duplicates, 182 studies were screened, excluding 110 via title/abstract review. Of 72 full-texts assessed, 65 were excluded (48 for irrelevant outcomes, 14 for incompatible metrics, 3 for lacking PM2.5-specific data), yielding 7 studies (n = 576,737 pregnancies) for meta-analysis. Using Cochran’s Q and I<ns3:sup>2</ns3:sup> statistics (I<ns3:sup>2</ns3:sup> = 85.1%, τ<ns3:sup>2</ns3:sup> = 0.027), a restricted maximum likelihood (REML) random-effects model estimated a pooled relative risk (RR) of 1.29 (95% CI: 1.10–1.50) per 10 μg/m<ns3:sup>3</ns3:sup> increase in PM2.5, indicating a 29% higher risk of depression. Subgroup analyses showed stronger effects across whole pregnancy (RR = 1.41, 95% CI: 1.23–1.63). High heterogeneity (I<ns3:sup>2</ns3:sup> = 85.1%) and publication bias (Egger’s p = 0.013) were noted. These findings highlight the impact of PM2.5 on maternal depression, urging further mechanistic studies, especially in low-income regions where data remains scarce.</ns3:p>