Factors across the life course predict women's change in smoking behaviour during pregnancy and in midlife: results from the National Child Development Study

BACKGROUND: Tobacco smoking before, during and after pregnancy remains one of the few preventable factors associated with poor health outcomes for mothers and their children. We investigate predictors across the life course for change in smoking behaviour during pregnancy and whether this change predicts smoking status in midlife. METHODS: Data were from the National Child Development Study (1958 British birth cohort). We included female cohort members who reported a first pregnancy up to age 33 years. Among 1468 women who smoked before pregnancy, we examined predictors reported in childhood (age 11 years), adolescence (age 16 years) and early adulthood (age 23 years) of change in smoking behaviour from 12 months before to during pregnancy using log-binomial regression. The association between change in smoking behaviour during pregnancy and smoking status in midlife (age 55 years) was examined while adjusting for predictors across the life course. RESULTS: Among prepregnancy smokers (39%), 26% reduced and 35% quit smoking during pregnancy. Parental smoking and lower social class during childhood, and early adulthood lower social class, depression, early smoking initiation, high smoking intensity, living with a smoker, no pregnancy planning and early motherhood were associated with lower probability of smoking reduction or cessation in pregnancy. Compared with women who smoked before and during pregnancy, women who reduced or quit were two times more likely to be non-smoker at age 55 years (95% CI 1.76 to 2.20). CONCLUSIONS: Findings from this population-based birth cohort study lend support for smoking cessation strategies that target those at risk at various stages across the life course