Smoking prevalence, reduction, and cessation during pregnancy and associated factors: a cross-sectional study in public maternities, Rio de Janeiro, Brazil.

BACKGROUND: Smoking epidemic in Brazilian women has later onset, smaller magnitude, and slower decreasing trend, compared to men. Among pregnant women, smoking has an additional deleterious effect. The purpose of this study was to analyze smoking prevalence during pregnancy and associated factors, and to describe the frequency of smoking reduction and cessation in public maternities of Rio de Janeiro State, southeastern Brazil, in 2011. METHODS: A cross-sectional study was conducted in two maternities located at public hospitals in two cities of the Rio de Janeiro state, Niterói (maternity A) and of Rio de Janeiro (maternity B). Data were gathered by interviews 12 hours after the delivery, and analyses of prenatal cards and medical records. Smoking prevalence according to maternal characteristics, adequacy of prenatal care, and proportions of smoking reduction and cessation during pregnancy were calculated. Factors associated to smoking during pregnancy were estimated by logistic regression analysis. RESULTS: Smoking prevalence at maternity A (24.8%, 95% CI: 21.1-29.0) and maternity B (17.9%, 95% CI: 15.8-20.1) were high. Prevalence rates were greater in women aged 20-34 years, mainly without partner, multiparous and brown or black skin color. Low education (OR = 2.14, 95% CI 1.21, 3.79) and multiparity (OR = 3.48, 95% CI 1.78, 6.81), at maternity A; adolescence (OR = 0.44, 95% CI 0.26, 0.75), black skin color (OR = 1.71, 95% CI 1.06, 2.74), low education (OR = 1.61, 95% CI 1.08, 2.40), and multiparity (OR = 1.58, 95% CI 1.03, 2.44), at maternity B, were associated with smoking in multivariable analysis. Adequacy of prenatal care and smoking prevalence showed an inverse association. More than half of the smokers kept the smoking habits during pregnancy. Reduction occurred mainly between the 1(st) and 2(nd) trimesters of pregnancy. CONCLUSION: Smoking prevalence during pregnancy was higher for multiparous and less educated women. Population and individual strategies for smoking prevention and control must include actions specific for women, especially during the reproductive period.