Among the most discouraging of state indicators for child well-being is Indiana’s disturbingly high rate of women who smoke while pregnant. The Annie E. Casey Foundation pegs Indiana’s percentage at 17.3 percent, compared with 10 percent nationally.

As Angela Mapes Turner’s Sunday report found, public health officials struggle in persuading expectant mothers to quit. But a glimpse at states with the lowest rates of expectant mothers who smoke suggests the most effective approach might be to discourage all residents from smoking.

Arizona boasts the best record when it comes to pregnant women and smoking. Just 4.9 percent of births are to women who smoke, according to the Casey report. Even the county with Arizona’s highest rate falls several percentage points behind Indiana’s statewide rate.

So what’s different in Arizona? A statewide smoking ban, for one.

Arizona residents approved the Smoke-Free Arizona Act in 2006. It prohibits smoking in most enclosed public places and workplaces, including bars. Just 15.9 percent of adults in Arizona are smokers, according to the Centers for Disease Control and Prevention’s Office on Smoking Health. In Indiana, where residents frequently cite individual rights in opposing a statewide ban, 26.1 percent of adults smoked in 2008, for the nation’s second-highest smoking rate.

The link between statewide bans and pregnant smokers isn’t limited to Arizona. Fewer than 6 percent of women who give birth in Connecticut and Utah are smokers; both states have comprehensive statewide smoking bans. West Virginia, where 27.9 percent of expectant mothers smoke, has no statewide smoking ban.

Supporters of a statewide ban, gearing up for another fight in the Indiana General Assembly, should add Indiana’s rate of pregnant smokers to their arsenal. The public health risks are indisputable.

Cigarette smoking during pregnancy is the single most important known cause of low-birthweight infants, with smokers nearly twice as likely to deliver a low-birthweight baby as non-smokers. Low-birthweight babies, in turn, are at increased risk for serious health problems as newborns, lasting disabilities and even death, according to the March of Dimes.

The success other states have had in reducing rates of pregnant smokers makes yet another compelling argument for Indiana to join the 35 states with statewide restrictions on smoking.