(Multinomial) logistic regression analysis of maternal smoking status throughout pregnancy on preterm birth and intrauterine growth in the Netherlands 2001–2007.

OR. Odds ratio.CI. Confidence interval.*Odds ratios are adjusted for maternal social factors (age, single motherhood, level of formal education country of birth). Results on gestational age are also adjusted for parity and gender of the newborn.$Extremely preterm: ≤28 completed weeks; very preterm: 28–31; moderately preterm: 32–36 weeks; term ≥37.