Environmental risk factors of pregnancy outcomes: a summary of recent meta-analyses of epidemiological studies

Table 2 Associations based on meta-analyses of air pollutants and birth outcomes

	Still birth	Gestational age/pre term delivery	Birth weight /low birth weight/ small for gestational age	Congenital anomalies
Environmental tobacco smoke	1.23 (1.09, 1.38) N=4 [18]	No stat sign association [19] No stat sign association [18]	Exposed vs. non exposed –60 g ( −80 g, -39 g) N=44 [19]-33 g (−16, -51) N=16 LBW 1.32, (1.07, 1.63) N=10 [20]	Exposed vs non exposed 1.18 (1.04, 1.34) N=12 [19] 1.13 (1.01, 1.26) N=7 [18]
Outdoor PM₁₀		No stat sign association N=7 [16]	No stat sign association N=11 [16]	Atrial septal defects 1.14 (1.01, 1.28)/10 μg/m³ N=4 [21]
Outdoor PM_2.5		PTB 1.15 (1.14, 1.16)/ 10 μg/m³ N=6 [16]	No stat sign association N=4 [16]	Too few studies
Outdoor NO₂				Coarctation of the aorta 1.20 (1.00, 1.44)/10 ppb N=4 Tetralogy of Fallot 1.25 (1.02,1.51)/10 ppb N=4 [21]
Outdoor SO₂				Coarctation of the aorta 1.04 (1.01, 1.08)/1 ppb N=4 Tetralogy of Fallot 1.04 (1.00, 1.08)/1 ppb N=4 [21]
Outdoor Ozone				No stat sign association [21]
Outdoor CO				No stat sign association [21]
Indoor air pollution from solid fuel use	1.51 (1.23, 1.85) Solid vs cleaner fuel N=4 [22]		Solid vs. cleaner fuel: -96.6 g (-68.5, -124.7) N=5 [22] LBW 1.38 (1.25, 1.52) N=8 [22]

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