Laws banning smoking in public places and workplaces in North America and Europe have been rapidly followed by large reductions in pre-term births and in children attending hospital for asthma treatment.

The study showed that rates of both preterm births and hospital attendances for asthma were reduced by 10% within a year of the smoking bans coming into effect.

The analysis was carried out on more than 2.5 million births and nearly 250,000 asthma exacerbations in North America and Europe.

According to the Lancet medical journal,which published the study, currently only 16% of the world's population is covered by comprehensive smoke-free laws, and 40% of children worldwide are regularly exposed to second-hand smoke.

"Our research found significant reductions in preterm birth and severe asthma attacks in childhood, as well as a 5% decline in children being born very small for gestational age after the introduction of smoke-free laws," said Dr Jasper Been of the Maastricht University Medical Centre, in the Netherlands, who led the study.

"Together with the known health benefits in adults, our study provides clear evidence that smoking bans have considerable public health benefits for perinatal and child health, and provides strong support for WHO recommendations to create smoke-free public environments on a national level," he added.

Ireland was the first country in Europe to introduce a smoking ban in pubs, resraurants and other workplaces, back in March 2004.

10% fall in heart attacks due to smoking ban.