The Effect of Local Smokefree Regulations on Birth Outcomes and Prenatal Smoking.

Objectives We assessed the impact of varying levels of smokefree regulations on birth outcomes and prenatal smoking. Methods We exploited variations in timing and regulation restrictiveness of West Virginia's county smokefree regulations to assess their impact on birthweight, gestational age, low birthweight, very low birthweight, preterm birth, and prenatal smoking. We conducted regression analysis using state Vital Statistics individual-level data for singletons born to West Virginia residents between 1995-2010 (N = 293,715). Results Only more comprehensive smokefree regulations were associated with statistically significant favorable effects on birth outcomes in the full sample: Comprehensive (workplace/restaurant/bar ban) demonstrated increased birthweight (29 grams, p < 0.05) and gestational age (1.64 days, p < 0.01), as well as reductions in very low birthweight (-0.4 %, p < 0.05) and preterm birth (-1.5 %, p < 0.01); Restrictive (workplace/restaurant ban) demonstrated a small decrease in very low birthweight (-0.2 %, p < 0.05). Among less restrictive regulations: Moderate (workplace ban) was associated with a 23 g (p < 0.01) decrease in birthweight; Limited (partial ban) had no effect. Comprehensive's improvements extended to most maternal groups, and were broadest among mothers 21+ years, non-smokers, and unmarried mothers. Prenatal smoking declined slightly (-1.7 %, p < 0.01) only among married women with Comprehensive. Conclusions Regulation restrictiveness is a determining factor in the impact of smokefree regulations on birth outcomes, with comprehensive smokefree regulations showing promise in improving birth outcomes. Favorable effects on birth outcomes appear to stem from reduced secondhand smoke exposure rather than reduced prenatal smoking prevalence. This study is limited by an inability to measure secondhand smoke exposure and the paucity of data on policy implementation and enforcement.