Maternal smoking during pregnancy: Trends and determinants in the conception to community study.

Background: Despite earlier declines, maternal smoking during pregnancy continues to be a public health problem. We examined trends and factors associated with maternal smoking during and between pregnancy over six years.

Methods: Participants were 27 532 pregnant women in Tasmanian public hospitals whose smoking status was gathered by midwives during perinatal care between July 2008 and June 2014. Generalized linear modeling was used to examine the trends in prevalence of maternal smoking over time and factors associated with change in smoking status both within and between pregnancies.

Results: Smoking during pregnancy decreased from 25.9% in 2008 to 16.4% in 2014 (57.9% decline). Multivariable regression analysis suggested that maternal alcohol consumption during pregnancy, living in a highly socioeconomically disadvantaged area, and being an Aboriginal or Torres Strait Islander significantly increased the risk of maternal smoking during pregnancy. Being older, married, or in a de facto relationship, and intending to breastfeed were associated with reduced risk of smoking during pregnancy. Between index (first birth recorded in data set) and last pregnancy, 35.1% of smokers quit, but 5.1% of nonsmokers started smoking. Only 8.1% of mothers who smoked during the first half of pregnancy quit by the second half.

Conclusions: Maternal smoking during pregnancy is decreasing. To sustain the decline, preventive efforts must address the role of social determinants of health (eg, mothers who drink alcohol, live in highly disadvantaged areas, are younger and single) among women who smoke during pregnancy.