Smoking bans reduce risk of preterm births: study

Smoke-free public areas are now common in Australia. AAP/Kalo Fainu

Smoking bans have been linked with a reduction in the risk of preterm baby deliveries in a new Belgian study.

The study, published on the British Medical Journal website today, included more than 600,000 babies born between 2002 and 2011 and found the risk of preterm births reduced with each phase of Belgium’s smoking bans in public places, restaurants, and bars serving food.

Researchers from Hasselt University found a reduction in the risk of preterm births of 3.13% after the ban on smoking in restaurants in 2007, and a further reduction in the risk of 2.65% after the 2010 ban on smoking in bars serving food.

No decreasing trend was evident in the years or months before the bans.

“Our study shows a consistent pattern of reduction in the risk of preterm delivery with successive population interventions to restrict smoking. It supports the notion that smoking bans have public health benefits even from early life,” said Tim Nawrot, associate professor of environmental epidemiology at Hasselt University’s Centre for Environmental Sciences.

The study is well conducted and adds more and more weight to the case for not exposing non-smokers to passive smoking, said Mike Daube, professor of health policy at Curtin University.

“When you work in public health you often have to wait about 50 years to see results. We’re seeing enormous benefits from people quitting smoking, but now were seeing benefits from protection from passive smoking and that’s terrific,” Professor Daube said.

Professor Daube pointed to a [recent UK study](]( that found childhood asthma admissions, which had been rising 2% a year before England put a strong smoke free law in place, dropped by 8.9% immediately after the law was introduced and continued to fall after that.

“This will add to the moves for protection of non smokers from passive smoking,” Professor Daube said.

Both smoking during pregnancy and exposure to second-hand smoke have been found to affect birth outcomes, yet little is known about the impact of recent smoke-free legislation on birth weight and preterm birth.

With smoking bans in Australia differing between states, it would be interesting to conduct a similar study in Australia, said Monique Robinson, associate principal investigator at the University of Western Australia’s Telethon Institute for Child Health Research.

“Sometimes with pregnancy the passive smoking message gets a bit lost,” Dr Robinson said.

She added that while the reduction to preterm births found in the study appeared relatively small, it could have big implications.

“Preterm birth comes with such a massive cost to society, but also to long term development things like asthma, general health, mental health. Although it’s a small reduction it could be a really important implication.”

Dr Robinson said smoking bans were part of the effort to encourage people to quit smoking, but it was important to consider home environments where fathers might smoke in the presence of their pregnant partner.

“This is the kind of study that could encourage fathers to quit smoking,” she said.