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Table 1 Meta-analysis summary pooled estimates for the effect of overall and subgroups of tobacco use on each growth outcome at birth

From: The association between active tobacco use during pregnancy and growth outcomes of children under five years of age: a systematic review and meta-analysis

  No. of studies No. of associations Pooled estimates Heterogeneity
X2 P I 2
SGA at birth    AOR a (95% CI)    
 All tobacco use (all of the below) 71 168 1.95 (1.76, 2.16) 21253.97 <0.001 99.2%
 Quit during pregnancy 14 25 1.17 (0.95, 1.44) 458.62 <0.001 94.8%
 Ever smoked during pregnancy 52 70 2.17 (1.82, 2.60) 17475.92 <0.001 99.6%
 Smoked 1-10 cigarettes/day 22 34 1.69 (1.59, 1.79) 118.70 <0.001 72.2%
 Smoked >10 cigarettes/day 23 37 2.53 (2.31, 2.78) 267.16 <0.001 86.9%
Length at birth    WMD b (95% CI)    
 All tobacco use (all of the below) 47 72 0.43 (0.41, 0.44) 1157.71 <0.001 93.9%
 Quit during pregnancy 4 4 -0.11 (-0.22, -0.01) 2.02 0.569 0.0%
 Ever smoked during pregnancy 40 44 0.46 (0.44, 0.48) 969.73 <0.001 95.6%
 Smoked 1-10 cigarettes/day 7 7 0.30 (0.21, 0.38) 15.56 0.016 61.4%
 Smoked >10 cigarettes/day 8 10 0.51 (0.37, 0.65) 34.87 <0.001 78.6%
Head circumference at birth    WMD b (95% CI)    
 All tobacco use (all of the below) 43 71 0.27 (0.25, 0.29) 707.87 <0.001 90.1%
 Quit during pregnancy 5 5 0.01 (-0.08, 0.11) 3.25 0.517 0.0%
 Ever smoked during pregnancy 37 41 0.28 (0.26, 0.30) 631.13 <0.001 93.7%
 Smoked 1-10 cigarettes/day 7 7 0.17 (0.08, 0.25) 5.04 0.539 0.0%
 Smoked >10 cigarettes/day 8 11 0.35 (0.25, 0.45) 24.40 0.010 54.9%
  1. aAOR, Adjusted odds ratio
  2. bWMD, Weighted mean difference