Group of studies | Model | Pooled unadjusted odds ratios (95% CI) | Test for heterogeneity | Pooled adjusted odds ratios (95% CI) | Test for heterogeneity | |
---|---|---|---|---|---|---|

Prenatal smoking (all studies) | REM | 2.74 (2.42 to 3.10) (n = 33) | χ^{2} (df = 32) = 120.7 (p<0.001) | 2.13 (1.86 to 2.43) (n = 18) | χ^{2} (df = 17) = 54.0 (p<0.001) | |

FEM | 2.74 (2.59 to 2.90) | 2.17 (2.04 to 2.31) | ||||

Prenatal smoking, studies with information on non-adjusted and adjusted odds ratios | REM FEM | 2.82 (2.38 to 3.33) (n = 15) 2.89 (2.70 to 3.09) | χ^{2} (df = 14) = 59.1 (p<0.001) | 2.18 (1.89 to 2.51) (n = 15) 2.20 (2.05 to 2.36) | χ^{2} (df = 14) = 40.7 (p<0.001) | |

Prenatal smoking (cohort studies) | REM | 2.75 (1.97 to 3.82) (n = 7) | χ^{2} (df = 6) = 22.2 (p = 0.001) | (n = 4)^{1-150} | χ^{2} (df = 3) 14.5 (p = 0.002) | |

FEM | 2.39 (2.15 to 2.65) | 2.04 (1.84 to 2.25) | ||||

Prenatal smoking (case-control studies) | REM | 2.73 (2.37 to 3.16) (n = 26) | χ^{2} (df = 25) = 78.8 (p<0.001) | 2.22 (1.88 to 2.61) (n = 14) | χ^{2} (df = 13) 37.0 (p<0.001) | |

FEM | 2.89 (2.71 to 3.09) | 2.26 (2.09 to 2.45) | ||||

Postnatal smoking | REM | 2.80 (2.00 to 3.93) (n = 9) | χ^{2} (df = 8) = 35.0 (p<0.001) | (n = 4)^{1-150}
^{1-151}
| χ^{2} (df = 3) = 1.18 (p= 0 .76) | |

FEM | 3.10 (2.70 to 3.56) | 1.94 (1.55 to 2.43) |