Impact of State Cigarette Taxes on Disparities in Maternal Smoking During Pregnancy

Objectives. We evaluated the impact of state tobacco control policies on disparities in maternal smoking during pregnancy.Methods. We analyzed 2000–2010 National Vital Statistics System natality files with 17 699 534 births from 28 states and the District of Columbia that used the 1989 revision of the birth certificate. We conducted differences-in-differences regression models to assess whether changes in cigarette taxes and smoke-free legislation were associated with changes in maternal smoking during pregnancy and number of cigarettes smoked. To evaluate disparities, we included interaction terms between maternal race/ethnicity, education, and cigarette taxes.Results. Although maternal smoking decreased from 11.6% to 8.9%, White and Black women without a high school degree had some of the highest rates of smoking (39.7% and 16.4%, respectively). These same women were the most responsive to cigarette tax increases, but not to smoke-free legislation. For every $1.00 cigarette tax increase, low-educated White and Black mothers decreased smoking by nearly 2 percentage points and smoked between 14 and 22 fewer cigarettes per month.Conclusions. State cigarette taxes may be an effective population-level intervention to decrease racial/ethnic and socioeconomic disparities in maternal smoking during pregnancy.A substantial literature has demonstrated the success of cigarette taxes on decreasing adult smoking.1–3 State taxes in 2013 ranged from $0.17 in Missouri to $4.35 in New York,4 and 2010 smoking levels in women were at 17%.5 Low-income adults, a group with the highest levels of smoking,5 have been shown to be more sensitive to tax increases.2,6 Despite racial/ethnic differences in smoking rates,5 less is known about whether responsiveness to taxes also varies.7 Over the past decade, many US states have enacted smoke-free legislation in the workplace, restaurants, or both in addition to increasing cigarette taxes. Although the aim of smoke-free policies is to protect nonsmokers from secondhand smoke, for which they have been very effective,8,9 the evidence for their impact on smoking rates is limited.1,9,10Despite these achievements, a population that has received little attention is pregnant women. The detrimental effects of smoking on maternal and fetal health11 and other household members through secondhand smoke exposure are well known.12 Although pregnancy is often a time of positive behavioral change, as of 2008, 10% to 15% of women smoked during pregnancy.13–15 However, these overall estimates masked racial/ethnic and socioeconomic gradients, such that 16% of White, 9% to 10% of Black, and 2% to 4% of Hispanic mothers smoked during pregnancy,14,15 and women with 12 or less years of education were more than 3 times (19.4%–22.3%) as likely to smoke during pregnancy as women with more than 12 years of education (6.5%).15Previous studies using data from the 1990s have found that pregnant women are responsive to cigarette tax increases.16–19 Ringel and Evans16 used population-level data from 1989 through 1995 and found that every $1.00 increase in cigarette taxes decreased smoking by 6.6 percentage points but had no effect on the number of cigarettes smoked daily. Specifically, they found that women who were White, older, and higher educated were the most responsive to tax changes.16 However, smoking patterns, social norms, and the politics related to tobacco control have changed over the past 20 years. A more recent study by Adams et al.20 used state-representative data from 2000 through 2005 to assess both tax changes and smoke-free policies on quitting during pregnancy. They found that a $1.00 cigarette tax increase was associated with a 4.8 percentage point increase in quitting smoking, and a full smoking ban at private worksites increased quit rates by 5.1 percentage points.20 However, they were unable to examine racial/ethnic or socioeconomic differences because of small sample sizes.A substantial gap in the literature remains, specifically, the effect of recent tobacco control policies on smoking levels among those mothers at the highest risk for smoking. We were able to use population-level data to exploit the natural experiment created through cigarette tax increases and the enactment of smoke-free legislation across and within US states over the past decade. Our first aim was to examine disparities in maternal smoking during pregnancy across and within racial/ethnic groups and, second, to evaluate the impact of state tobacco control policies on disparities in maternal smoking.