Interdicting smoking in public places may benefit the soon-to-be members of society. Results of a new study published in British Medical Journal confirmed that the smoke-free regulations substantially reduced the incidence of babies born prematurely.

Adverse effects of passive smoking

Numerous studies have associated second-hand smoking to a host of health issues such as heart disease, some cancers and asthma flare ups. Research also showed that expecting women exposed to passive smoking were at higher risks of giving birth to a preterm baby; that is an infant born before the 37th week of gestation.

According to the authors, even a mild decrease in gestational age may have detrimental health ramifications on the child in early and later life. In another study, babies who were born late preterm (in the 34th to 36th weeks of pregnancy) also had a 13 to 50% increased risk of mortality in young adulthood.

Study details

In order to determine whether smoke-free laws helped reduce the incidence of premature births, the researchers analysed birth data in Belgium from January 2002 to December 2011. This covered periods before, during and after the introduction of these legislations which occurred in three phases: in January 2006, 2007 and 2010.

The study population involved 606,877 live babies born between the 24th and 44th weeks of gestation. The researchers considered only ‘singleton’ babies since twins and other multiple births are more likely to be born early.

Study findings

There was no change in the trend of preterm births in the years or months preceding the bans. The preterm birth rate started declining only slowly after the introduction of the first phase of the legislation — in January 2006, smoking was banned in public places and most workplaces.

The authors reported the most significant changes in preterm birth rate after the 2nd and 3rd phases were implemented. They noted a 3.13% drop in the occurrence of preterm births in January 2007 corresponding to the ban on smoking in restaurants. This was followed by a further 2.65% annual reduction in the frequency of premature deliveries when bars serving food became smoke-free in January 2010.

The academics wrote that ‘these changes correspond to a reduction of six preterm births per 1000 deliveries over the five study years (after 2007).’

The researchers explained that the less pronounced reduction in preterm deliveries following the smoking ban at work was probably because the 1st phase of the non-smoking regulation took place more gradually than the other bans.

The results were consistent even after adjustment for several factors including the mothers’ ages and changes in air pollution.

Additional benefits of the smoking bans

In a British study published earlier this year, findings indicated that the implementation of smoking bans saw a rapid and impressive drop in the number of children admitted to hospital because of an asthma attack.

And a 2009 study found that smoke-free regulations involving public places in the UK led to a sharp and considerable decrease in the number of heart attacks, saving the NHS £8.4 million during the initial year.


    Cox et al (2013) Impact of a stepwise introduction of smoke-free legislation on the rate of preterm births: analysis of routinely collected birth data. BMJ. 346:f441.