Association of Maternal Smoking Status on Breastfeeding Practice — Missouri Pregnancy Related Assessment and Monitoring System, 2005

Purpose In Missouri, 66% of infants are ever breastfed, compared with 73% nationally. Approximately 28% of Missouri women of childbearing age smoke and 18% smoke daily during pregnancy. Smoking during and after pregnancy increases the risk for low birthweight, respiratory infections, and asthma, increasing the risks for adverse outcomes in exposed infants. Methods The Missouri Pregnancy Related Assessment and Monitoring System was a population-based survey conducted in 2005 among a sample of new mothers, stratified by birthweight and residence. Surveys were mailed, with telephone follow-up to, and completed within 2–12 months postpartum. Smokers were classified as previous (quit during pregnancy), light (≤10 cigarettes/day), and heavy (>10/day). Multivariable logistic regression and proportional hazards models were used to assess breastfeeding initiation and duration, by smoking status, controlling for confounding factors. SUDAAN® was used to account for the complex sampling design. Results The weighted response rate was 61% (N=1789). Compared with nonsmokers, heavy (adjusted odds ratio [aOR]=1.6; 95% confidence interval [CI]=1.0–2.6) and light (aOR=1.6; 95% CI=1.0–2.4) smokers were less likely to initiate breastfeeding, after controlling for age, race, education, marital status, prenatal care, Medicaid, presence of another household smoker, pre-pregnancy body mass index and prolonged infant hospitalization. Heavy (adjusted hazards ratio [aHR]=1.9; 95% CI=1.4–2.7), light (aHR=1.8; 95% CI=1.3–2.4), and previous (aHR=1.6; 95% CI=1.1–2.5) smokers were more likely to wean at any given time, compared with nonsmokers, controlling for the same confounding factors. Conclusions Smoking mothers are less likely to initiate breastfeeding and more likely to wean earlier than nonsmoking mothers. Prenatal breastfeeding and smoking cessation counseling should address the negative effects of smoking on both fetal development and breastfeeding.