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Table 2 Associations between birth weight, SGA z score, and tobacco smoke exposure

From: Prevalence of maternal smoking and environmental tobacco smoke exposure during pregnancy and impact on birth weight: retrospective study using Millennium Cohort

  Non-smoker, non ETS exposed Non-smoker ETS exposed Active smoker
Birth weight (in Kg) N = 8091 N = 2256 N = 6395
Mean Birthweight (SE)† 3.448 (0.007) 3.389 (0.014) 3.279 (0.009)
Crude mean difference compared to Non-Smoker, Non ETS exposed (95% CI) - -0.059 (-0.090 to -0.027)
p < 0.001
-0.168 (-0.191 to -0.146)
p < 0.001
Adjusted Mean difference* (95% CI) - -0.036 (-0.067 to -0.005)
p = 0.025
-0.146 (-0.171 to -0.122)
p < 0.001
SGA z score N = 8024 N = 2228 N = 6338
Mean Z score (SD)† 0.077 (0.014) 0.006 (0.026) -0.237 (0.016)
Crude mean difference compared to Non-Smoker, Non ETS exposed (95% CI) - -0.070 (-0.128 to -0.013)
p = 0.016
-0.314 (-0.354 to -0.273)
p < 0.001
Adjusted Mean difference* (95% CI)   -0.038 (-0.093 to 0.018)
p = 0.18
-0.275 (-0.319 to -0.231)
p < 0.001
  1. * Adjustment was made for maternal age, BMI, parity, alcohol use, maternal education, ethnicity, income, gestational diabetes.
  2. † All results are adjusted for the sampling design