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Table 3 Association between smoking before pregnancy (yes/no) and neonatal outcome

From: Pregnancy planning, smoking behaviour during pregnancy, and neonatal outcome: UK millennium cohort study

  Neonatal outcome in mothers Neonatal outcome in    
  who did not smoke before mothers who smoked* Crude1 Adjusted 1 ** Adjusted 2***
  or during their pregnancy before pregnancy    
n/N (%) n/N (%) OR (95% CI) OR (95% CI) OR (95% CI)
Low birth weight (<2.5 kg) 569/11,429 (5.00) 501/6,017 (8.33) 1.73 (1.42-2.05) 1.98 (1.62-2.41) 1.91 (1.56-2.34)
Prematurity (< 37 weeks gestation) 748/11,352 (6.59) 485/5,966 (8.13) 1.25 (1.09-1.45) 1.14 (0.96-1.35) 1.12 (0.95-1.35)
  1. 1The baseline group was women who did not smoke during pregnancy.
  2. *Including women who reduced or quit smoking at some time during pregnancy.
  3. **All adjusted for mother’s age and mothers education. Birth weight is also adjusted for ethnicity, religion and BMI. Prematurity also adjusted for relationship status.
  4. ***Adjusted for the same variables as model 1 plus planning.