MORE than 1,000 pregnant women have taken part in a scheme which offers them up to £600 in shopping vouchers to give up smoking.

Over half of the mothers-to-be who signed up the NHS Tayside project had quit smoking after four weeks while 354 - out of a total of 1,026 - had given up after three months.

Under the 'Give it up for baby' scheme, which has been running since 2009, women receive £12.50 on an Asda gift card for every week they can prove they have not smoked. The money is available until the baby is three months old.

It comes after research published in the BMJ showed pregnant women were more likely to stop smoking if they were offered a financial reward.

Although the schemes can be controversial, anti-smoking campaigners have said that even modest financial incentives can have a noticeable impact among smokers in deprived areas.

Sheila Duffy, chief executive of Ash Scotland, said: "Voucher schemes are cost-effective when you consider the significant financial implications of tobacco use for the NHS and wider society."

Separate research published last week showed that smoking while pregnant causes chemical changes to the DNA of a foetus detectable from as early as 12 weeks. The study also indicated that children born to smokers may be predisposed to a range of lifelong health conditions.

Andrew Radley, consultant in public health pharmacy for NHS Tayside, said: "Smoking in pregnancy can cause a wide range of health problems for the unborn child, increase childhood illness and affect the long-term health of the mother.

"We have found that many more smokers engage with Give it up for baby than wit previous interventions we have offered."