COMPLICATIONS in pregnancy have fallen as a result of the ban on smoking in public places.

The introduction of the ban in Scotland has resulted in a reduction in the number of babies being born early and underweight, the research, led by Professor Jill Pell, of the Institute of Health and Wellbeing at Glasgow University, claims.

The study, published in the online journal PLoS Medicine, showed a decrease in pre-term delivery in pregnancy – or the birth of a baby less than 37 weeks in the womb – and babies who are small for their age.

It looked at statistics for pre-term delivery and gestational age in 716,941 single-baby births before and after the introduction of the smoking legislation on March 26, 2006.

The researchers found that following the introduction of the smoking ban the number of mothers who smoked fell from 25.4% to 18.8%.

There was also a drop of more than 10% in overall pre-term deliveries, a 5% fall in the number of infants born small for gestational size, and an 8% decrease in the number of babies born very small for their time in the womb.

Ms Pell said: "These findings add to the growing evidence of the wide-ranging health benefits of smoke-free legislation and support the adoption of such legislation in other countries which have yet to implement smoking bans. These reductions occurred both in mothers who smoked and those who had never smoked.

"While survival rates for pre-term deliveries have improved over the years, infants are still at risk of developing long-term health problems so any intervention that can reduce the risk of pre-term delivery has the potential to produce important public health benefits."

The researchers looked at data for babies born between January 1996 and December 2009 extracted from the Scottish Morbidity Record (SMR2) which collected information on all women discharged from Scottish maternity hospitals, including maternal and infant characteristics, obstetric history, clinical management and pregnancy complications.

This data also includes postcode details and allowed socioeconomic factors to be incorporated.

Ms Pell noted: "Irrespective of legislation, many women quit smoking when pregnant because of concerns regarding their infant's health, and there has been increased awareness of the need to protect children from exposure to tobacco smoke.

"The potential for tobacco control legislation to have a positive effect on health is becoming increasingly clear."

While premature is often used to describe pre-term birth, it is also detailed as a baby weighing less than 2500g or an infant who is not developed enough to survive on its own after birth.

The research paper, entitled Impact of Scotland's Smoke-free Legislation on Pregnancy Complications: Retrospective Cohort Study, was funded by the Chief Scientist Office.

A report in The Lancet outlined the benefits Scotland has experienced since the introduction of smoke-free laws in public premises.

It stated that implementation of strong smoke-free laws has "generally been followed by rapid decreases in hospital admissions for acute myocardial infarction".

The average decline was 17% across a number of countries including the US, Italy, Scotland and France one year after the laws took effect and grew to about 30% after three years.

The report in the medical journal last September also stated that in Scotland there was a 13% decrease per year in childhood asthma admissions since the ban.

Health benefits for others have also been cited, with previous research claiming non-smokers who breathe in second-hand smoke have around a 25% higher risk of getting lung cancer or heart disease.

It has been claimed as many as 1000 pubs have closed in Scotland since the ban.