摘要：Ba c k g r o u n d: A growing body of evidence has associated maternal exposure to air pollution with adverse effects on fetal growth; however, the existing literature is inconsistent.oB j e c t i v e s: We aimed to quantify the association between maternal exposure to particulate air pol-lution and term birth weight and low birth weight (LBW) across 14 centers from 9 countries, and to explore the influence of site characteristics and exposure assessment methods on between-center heterogeneity in this association.Me t h o d s: Using a common analytical protocol, International Collaboration on Air Pollution and Pregnancy Outcomes (ICAPPO) centers generated effect estimates for term LBW and continu-ous birth weight associated with PM10and PM2.5(particulate matter ≤ 10 and 2.5 μm). We used meta-analysis to combine the estimates of effect across centers (~ 3 million births) and used meta-regression to evaluate the influence of center characteristics and exposure assessment methods on between-center heterogeneity in reported effect estimates.re s u l t s: In random-effects meta-analyses, term LBW was positively associated with a 10-μg/m3increase in PM10[odds ratio (OR) = 1.03; 95% CI: 1.01, 1.05] and PM2.5(OR = 1.10; 95% CI: 1.03, 1.18) exposure during the entire pregnancy, adjusted for maternal socioeconomic status. A 10-μg/m3increase in PM10exposure was also negatively associated with term birth weight as a continuous outcome in the fully adjusted random-effects meta-analyses (–8.9 g; 95% CI: –13.2, –4.6 g). Meta-regressions revealed that centers with higher median PM2.5levels and PM2.5:PM10ratios, and centers that used a temporal exposure assessment (compared with spatiotemporal), tended to report stronger associations.co n c l u s i o n: Maternal exposure to particulate pollution was associated with LBW at term across study populations. We detected three site characteristics and aspects of exposure assessment meth-odology that appeared to contribute to the variation in associations reported by centers
