Background and aims Secondhand smoke (SHS) has harmful effects on the health of non-smokers and it has also been associated with low birth weight and preterm births. In recent years, many countries have implemented tobacco control legislations to protect non-smokers from SHS exposure. This study evaluates the correlation between tobacco control policies— particularly smoking bans in work and public places—and the prevalence of preterm births and low birth weight in the European Union (EU).

Methods This is an ecological study, the unit of analysis is set at the country level, (including data from 25 countries). The Tobacco Control Scale (TCS), which reflects the level of implementation of smoke-free legislations, was obtained from all EU countries. Prevalence data for preterm births and low birth weight were obtained from two sources: the European Perinatal Health Report (EPHR), which provides data from 25 countries, and the Eurostat data, which includes data from 12 countries. We analysed the correlation between the TCS score and the prevalence of preterm birth and low birth weight in the EU countries by means of Spearman (rsp) rank-correlation coefficients and their 95% confidence intervals (95% CI). One of the policies of the TCS was analysed in detail looking for a relation between the restriction of smoking in public and work places and preterm birth or low birth weight.

Results The 2010 TCS was negatively correlated with the prevalence of preterm births before week 37 (rsp=−0.46; 95% CI:−0.731,–0.013; p=0.024) and with the prevalence of the low birth weight. However, this second correlation was not statistically significant (<2500 grams, rsp=−0.325; 95% CI: −0.591, 0.050; p=0.113 and<1500 grams, rsp=−0.306; 95% CI: −0.683, 0.127; p=0.137) in European countries in 2010. A statistically significant inverse correlation was found between the level of restrictions on smoking in public places and the prevalence of low birth weight (<2500 grams rsp: −0.422; 95% CI:−0.772, 0.023; p=0.036). Similar negative correlations were found between TCS (2013) and the prevalence of preterm birth in 2013 and 2014 and the prevalence of low birth weight.

Conclusion The level of smoke-free legislations in European countries correlates with lower preterm birth prevalence rates at the ecological level. Given the effects of preterm births on the public health system, these data support a more extensive application of tobacco control policies.