Association Between Cessation and Continuation of Smoking During Pregnancy and Exclusive Breastfeeding: A Population-based Study

Background: Maternal smoking is consistently associated with suboptimal breastfeeding behavior across different contexts. Pregnancy offers a window of opportunity for smoking cessation owing to perceived risk to infant health outcome. Weather discontinuing smoking during pregnancy makes a difference in exclusive breastfeeding practice is not reported in population-based studies. We aimed to examine the association of cessation and continuation of smoking during pregnancy with exclusive breastfeeding practice in a representative Canadian household population.

Methods: We used the public use microdata file from the Canadian Community Health Surveys (CCHS) 2015–2018. The pooled sample of 9,860 women who had maternal experience with a child under five years of age at the time of survey was included in the analysis. Self-reported smoking status in pregnancy was categorized as continuation of smoking in the last three months of pregnancy; cessation after finding out pregnancy; and never smoked or no smoking prior to pregnancy. We used multivariable logistic regression to examine the association between exclusive breastfeeding and smoking status during pregnancy. Sociodemographic variables known to be associated with exclusive breastfeeding including maternal age, education, immigration status, aboriginal status, household income, employment status, marital status, and household food insecurity were included in the regression model for adjustment. Sampling weights provided by Statistics Canada were applied while estimating proportions and Odds Ratios (ORs) to address the design effects.

Results: The overall prevalence of exclusive breastfeeding until six months of age in the pooled sample was 33.2% (95% CI:31.7,34.8). The prevalence of exclusive breastfeeding was higher among those who did not smoke before pregnancy (34.4%; 95% CI 32.8,36.1) followed by those who quit smoking during pregnancy (25.7%; 95% CI 20.2,32.2) and lowest among those who continued to smoke in the last three months of pregnancy (15.7%; 95% CI 10.8,22.2). Exclusivity of breastfeeding was positively associated with maternal age 35 years or more, being an immigrant residing in Canada for ten years or longer, being employed in last 12 months and having annual household income >$20,000. The odds of exclusive breastfeeding were significantly lower among those who continued smoking during pregnancy compared to those who were non-smokers before pregnancy (adjusted OR 0.53; 95% CI 0.33,0.83). However, the odds of exclusive breastfeeding was not significantly different for mothers who quit smoking after finding out pregnancy compared to those who did not smoke prior to pregnancy (adjusted OR 0.82; 95% CI 0.57,1.17).

Conclusion: We observed significantly lower exclusive breastfeeding till six months among women who continued smoking during pregnancy compared to non-smokers but no significant difference in exclusive breastfeeding among those who quit smoking after finding out pregnancy compared to non-smokers. The findings thus support smoking cessation interventions during the prenatal visits to improve exclusive breastfeeding practice.