Smoke-Free Legislation in Spain and Prematurity

Abstract

Background and objective: Spain implemented a partial smoking ban in 2006 followed by a comprehensive ban in 2011. The objective was to examine the association between these smoke-free policies and different perinatal complications. Methods: Cross-sectional study including all live births between 2000 and 2013. Selected adverse birth outcomes were: preterm births (<37 gestational weeks), small for gestational age (SGA; <10th weight percentile according to Spanish reference tables), and low birth weight (<2500 g). We estimated immediate and gradual rate changes after smoking bans by using overdispersed Poisson models with different linear trends for 2000 to 2005 (preban), 2006 to 2010 (partial ban), and 2011 to 2013 (comprehensive ban). Models were adjusted for maternal sociodemographics, health care during the delivery, and smoking prevalence during pregnancy. Results: The comprehensive ban was associated with preterm birth rate reductions of 4.5% (95% confidence interval [CI]: 2.9%-6.1%) and 4.1% (95% CI: 2.5%-5.6%) immediately and 1 year after implementation, respectively. The low birth weight rate also dropped immediately (2.3%; 95% CI: 0.7%-3.8%) and 1 year after the comprehensive ban implementation (3.5%; 95% CI: 2.1%-5.0%). There was an immediate reduction in the SGA rate at the onset of the partial ban (4.9%; 95% CI: 3.5%-6.2%), which was sustained 1 year postimplementation. Although not associated with the comprehensive ban at the onset, the SGA rate declined by 1.7% (95% CI: 0.3%-3.1%) 1 year postimplementation. Conclusions: The implementation of the Spanish smoke-free policies was associated with a risk reduction for preterm births and low birth weight infants, especially with the introduction of the more restrictive ban.