Clustering of socioeconomic, behavioural, and neonatal risk factors for infant health in pregnant smokers

Tobacco smoking is a major cause of morbidity and mortality, including during pregnancy. Although effective ways of promoting smoking cessation during pregnancy exist, the impact of these interventions has not been studied at a national level. We estimated the prevalence of smoking throughout pregnancy in the Netherlands and quantified associations of maternal smoking throughout pregnancy with socioeconomic, behavioural, and neonatal risk factors for infant health and development. Data of five national surveys, containing records of 14,553 Dutch mothers and their offspring were analyzed. From 2001 to 2007, the overall rate of smoking throughout pregnancy fell by 42% (from 13.2% to 7.6%) mainly as a result of a decrease among highly educated women. In the lowest-educated group, the overall rate of smoking throughout pregnancy was six times as high as in the highest-educated group (18.7% versus 3.2%). Prenatal tobacco smoke exposure was associated with increased risk of extremely preterm (