Table 1.

Summary of meta-analyses results related to preterm birth or infant low birth weight and PM_2.5 exposure across pregnancy

Reference	Odds ratio for preterm birth (95% CI)	Odds ratio for low birth weight (95% CI)	Effect estimate (g) for every10 μg/m3 increase in PM2.5
Stieb et al. [10]	1.05 (0.98, 1.13) n = 4	1.05 (0.99, 1.12) n = 6	−23.4 (−45.5, −1.4) n = 7
Zhu et al. [11]	1.10 (1.03, 1.18) n = 8	1.05 (1.02, 1.07) n = 6	−14.6 (−19.3, −9.9) n = 12
Lamichhane et al. [12]	1.13 (0.98, 1.28) n = 5	NA	−22.2 (−37.9, −6.4) n = 7
Sun et al. [13]	NA	1.09 (1.03, 1.15) n = 19	−15.9 (−26.8, −5.0) n = 17