Scotland has seen a 10 per cent reduction in premature births following its smoking ban, introduced in 2006.
After the legislation was introduced in Scotland, fewer mothers-to-be smoked - 19 per cent compared with 25 per cent before.
The University of Glasgow researchers who carried out the study analysed smoking and birth rates for all expectant women in Scotland before and after the ban - and included data for more than 700,000 women spanning a period of about 14 years.
Dr Daniel Mackay, who led the research, said the findings "add to the growing evidence of the wide-ranging health benefits of smoke-free legislation" and "lend support" to the adoption of such legislation in countries where it does not currently exist.
Tobacco smoke has been linked to poor foetal growth and placenta problems.
However Andy Cole, Chief Executive of Bliss said: "We welcome the findings of this new study, which highlights a reduction in the number of babies born early or with low birthweight in Scotland, where around 8,000 babies are born each year needing specialist hospital care.
"Bliss always recommends that women should not smoke during pregnancy and that they should lead a healthy lifestyle. However, it is important to remember that the reasons a baby can be born premature or underweight are complicated and that smoking is just one risk factor."
Article posted by Robert Mair on 07/03/2012