Revealed: One in six Wolverhampton mums-to-be smoke during pregnancy

Sandwell is the only area of the Black Country to see an increase, with 10.5 per cent of mothers-to-be lighting up, compared to 10 per cent last year.

Wolverhampton still has the region's highest number, with 16.9 per cent, but it has dropped from 18.8 per cent.

Cannock was the only other local area to see an increase, from 10.4 per cent to 12.1 per cent.

Walsall's fell from 14.7 to 14.1 per cent, Dudley's from 15.7 to 15.1 per cent, and Stafford's from 14.5 to 9.5 per cent.

From April to June this year, a total of 675 women were recorded as smoking at the time of birth, leading to fears unborn babies are being caused serious harm.

According to the latest figure from the Health and Social Care Information Centre, the number of pregnant women smoking across England dropped by 0.6 per cent.

Experts say smoking during pregnancy can cause serious pregnancy-related health problems.

These include complications during labour and an increased risk of miscarriage, premature birth, low birth-weight and sudden unexpected death in infancy.

Sandwell's director of health, Jyoti Atri, said: "We have been working closely with Sandwell and West Birmingham NHS Trust to actively identify pregnant smokers.

"They have recently introduced routine carbon monoxide tests for pregnant women and this is probably why we have seen a recent increase.

"The details of all of the pregnant smokers are then shared with our service and they are offered smoking cessation support, through one of our smoking cessation providers."

Professor Kevin Fenton, director of health and well-being at Public Health England (PHE), said: "There are still significant differences across regions and social groups - with the burden and harm hitting hardest in more deprived communities.

"Stopping smoking is the best thing a woman and her partner can do to protect their own health and the health of their baby, both during pregnancy and after.

"Quitting and remaining smoke free can be difficult, and like many smokers expectant parents may need help.

"Women who smoke need to know that they are increasing the chances of abnormal fetal growth and risking their baby being stillborn."

Despite the shocking results in the West Midlands, across England, the figures are the lowest since records began in 2006/07, with 70,880 out of 622,640 maternities last year involving women who smoked.