Research Article: Prevalence of pre-gestational and gestational smoking and factors associated with smoking cessation during pregnancy, Brazil, 2011-2012

Date Published: May 24, 2019

Publisher: Public Library of Science

Author(s): Rosa Maria Soares Madeira Domingues, Valeska Carvalho Figueiredo, Maria do Carmo Leal, Abraham Salinas-Miranda.

http://doi.org/10.1371/journal.pone.0217397

Abstract

Gestational smoking is associated with various adverse maternal and fetal outcomes. Over the last three decades, despite considerable advances in tobacco control policy in Brazil, gestational smoking has caused a considerable number of fetal deaths and disabilities. The aim of this study is to estimate the prevalence of pre-gestational and gestational smoking and to identify the factors associated with smoking cessation up to the 20th gestational week. Methods: “Birth in Brazil” was a nationwide hospital-based study conducted from February 2011 to October 2012. Smoking prevalence and smoking cessation during pregnancy was estimated through face-to-face interviews with postpartum women during hospitalization for birth care. We performed multivariate logistic regression to verify the factors associated with smoking cessation up to the 5th month of pregnancy. Results: prevalence of pre-gestational smoking of 16.1% (CI 95% 15.3%-16.9%); prevalence of smoking any time during pregnancy of 9.6% (CI 95% 9.0%-10.3%); and prevalence of smoking cessation up to the 5th month of pregnancy of 56.7% (CI 95% 54.0%-59.4%). The factors associated with smoking cessation were residence in the North, Northeast, and Central-West of Brazil, having received at least one prenatal consultation (OR 3.51 CI 95% 1.85–6.67), more years of schooling (15 or more vs less than 7 years of schooling OR 5.54 CI 95% 2.97–10.34), living with a partner (OR 1.35 CI 95% 1.01–1.79), no children prior to the index pregnancy (OR 2.77 CI 95% 2.13–3.61), and absence of alcohol use (1.74 CI 95% 1.39–2.18) or of suspected alcohol abuse (OR 1.62 CI 95% 1.07–2.45). Conclusion: The estimated smoking rate during pregnancy in Brazil is still high and is associated with factors of increased maternal social vulnerability, which may contribute to the increased occurrence of unfavorable perinatal outcomes.

Partial Text

Smoking during pregnancy is a major public health problem, associated with various adverse maternal and fetal outcomes [1]. Maternal smoking during pregnancy increases the risk of ectopic pregnancy, placenta previa, placental abruption, and miscarriage [2–4]. Studies have consistently identified an association between smoking during pregnancy and prematurity, intrauterine growth restriction, small for gestational age newborns, and cleft lip [2, 5–9]. A meta-analysis of 34 articles from around the world showed that smoking during pregnancy increases the risk of stillbirth by 47% and that the risk is dose-dependent [10].

“Birth in Brazil” (NB) was a nationwide hospital-based study conducted from February 2011 to October 2012 that aimed to assess the conditions in prenatal, labor, and childbirth care in the country and the results of this care.

Of the 23,894 women interviewed, 16.1% reported pre-gestational smoking, 9.6% reported smoking at some time in the pregnancy, and 6.8% reported smoking throughout the pregnancy. Of the pregnant women that reported smoking up to the 5th month of pregnancy, 79.1% smoked daily, with a prevalence of 7.3% and mean daily consumption of 10.6 cigarettes. Among the pregnant women that smoked after the 5th month of pregnancy, these figures were 80.8%, 5.8%, and 9.9, respectively. Approximately 65% of the women that reported smoking up to the 5th month of pregnancy reduced their consumption of cigarettes during the pregnancy (frequency and/or amount), while 42.5% reported having quit smoking throughout the entire pregnancy (Table 1).

“Birth in Brazil” is the first nationwide study to assess prenatal, labor, and childbirth care in the country. Its sound methodology with clear inclusion criteria of hospitals and women, adequate sample size, appropriate sampling and data collection procedures to avoid selection and information bias, as well as appropriate data analysis, has provided information around many aspects of pregnancy and childbirth care. Therefore, our results represent the best national estimates of prevalence rates for smoking and smoking cessation during pregnancy and the associated factors. In a country with comprehensive measures of tobacco control and downward trend in smoking prevalence, little was known about smoking during pregnancy at the national level. By filling this gap, this study has provided the necessary knowledge for the induction of specific measures aimed at this population group and might be used as baseline for future evaluation studies.

The estimated smoking rate during pregnancy in Brazil is still high and is associated with factors of increased maternal social vulnerability, which may contribute to the increased occurrence of unfavorable perinatal outcomes. The lower coverage of prenatal care in these women and the less adequate care may be contributing to lower smoking cessation rates in this group.

 

Source:

http://doi.org/10.1371/journal.pone.0217397