Prevalence of smoking during pregnancy and associated risk factors among Canadian women: a national survey

Background: Cigarette smoking carries a threat both to the expecting mother and her newborn. Data on the prevalence and predictors of smoking during pregnancy is limited in Canada. Canadian studies are mainly representative of specific cities and/or provinces. Therefore, the study aims to assess the prevalence of smoking during pregnancy and its associated risk factors throughout the Canadian provinces and territories. Methods: The analysis was based on the Maternity Experience Survey targeting women aged >= 15 years who had singleton live births during 2005/06 in the Canadian provinces and territories. The outcome was ever smoking during the thirst trimester of pregnancy. Socio-economic factors, demographic factors, maternal characteristics, and pregnancy related factors that proved to be significant at the bivariate level were considered for a logistic regression analysis. Bootstrapping was performed to account for the complex sampling design. Results: The sample size was 6,421 weighted to represent 76,508 Canadian women. The prevalence of smoking during pregnancy was 10.5%, whereby smoking mothers consumed on average 7 cigarettes a day (95% Confidence interval CI: 6.5-7.4; SD = 5.7). Regression analysis revealed that mothers who smoked during pregnancy were more likely to be of low socio-economic status, non-immigrant, single and passive smokers during pregnancy. Not attending prenatal classes and experiencing stressful events before/during pregnancy also increased the mothers' odds of smoking during pregnancy. While the age of the mother's first pregnancy was negatively associated with smoking during pregnancy, the mother's current age was positively associated with it. Conclusion: Smoking during pregnancy is still prevalent among Canadian women. The findings may be useful to enhance smoking prevention programs and integrated health promotion strategies to promote positive health behaviors among disadvantaged pregnancies.