New research from Belgium has strengthened the theory that public smoking bans cut the number of children born prematurely.
A study of 600,000 births conducted by the Hasselt University found three successive drops in babies born before 37 weeks in Belgium, each occurring after a phase of a public smoking ban was introduced.
Scottish research in 2012 found a similar pattern in that country and study lead Dr Tim Nawrot said that the research shows "a consistent pattern of reduction in the risk of preterm delivery" unseen before the smoking ban.
But the researchers could not fully state the smoking ban was the cause of the change as pre-term births had started to drop before the first phase of the ban.
There were three phases to the ban in Belgium with public places and workplaces first to introduce smoke-free rules in 2006, followed by restaurants in 2007 and bars serving food in 2010.
The rate of premature births was found to fall after each phase of the ban with the biggest impact seen after the second two bans with restaurants and bars introducing no smoking rules.
After the bans in 2007 and 2010, the premature birth rate dropped by around 3% each time. Overall it corresponds to a fall of six premature babies in every 1,000 births.
The changes, reported in the British Medical Journal, could not be explained by other factors such as mother's age and socioeconomic status or population effects such as changes in air pollution and influenza epidemics.
Royal College of Midwives director of midwifery Louise Silverton welcomed the findings but said that more still needs to be done to reduce pregnant women's exposure to second-hand smoke.
"There is no doubt because it is supported by a large body of evidence, of the negative impact of smoking on the pregnant woman and her developing child and of the effects of second-hand smoke," she added.
"This research is encouraging but we should also be aware that many pregnant women are still exposed to second-hand smoke in domestic situations. We would hope that smokers would be considerate and refrain from smoking when pregnant women are in their immediate vicinity."
Posted 15/02/2013 by firstname.lastname@example.org