Three stop-smoking advisers have been taken on to help pregnant women quit.

The move comes after health bodies revealed more babies in Leicestershire died before they reached their first birthday than most other places in the country.

Some of the babies are born prematurely, others with inherited conditions. The number also includes children killed in accidents.

However, a major concern for public health officials is the number of mums-to-be who smoke.

It is estimated one woman in four – about 2,200 in Leicestershire – smokes while they are pregnant.

Of those, about 700 quit before they give birth.

Smokers inhale more than 4,000 chemicals from each cigarette. One, carbon monoxide, restricts the oxygen that is essential for a baby's development.

As a result, their heart has to beat harder whenever cigarette smoke is inhaled by a pregnant woman.

Babies affected by cigarette smoke are also more likely to be born prematurely and with a low birth weight.

Louise Ross, manager of the city's Stop! smoking service, said: "We don't know exact numbers of babies born prematurely or which would have been heavier if their mothers hadn't smoked.

"But we do know that small, poorly or pre-term babies can be the results of smoking."

Latest figures showed that between 2005 and 2007, for every 1,000 babies born in Leicester more than six died before they reached their first birthday. In the county, the figure was 5.1 per 1,000 births.

Both are above the English average of 4.9.

It means every week at least one set of parents is grieving for a lost son or daughter.

Amanda Armstrong, from Thrussington, began smoking when she was just nine. For years – including through three pregnancies – she got through up to 30 cigarettes a day.

When she discovered she was having her fourth baby, she was determined to quit forever.

The 39-year-old said: "It was hard at the start and still is from time to time, but it is getting easier."

Her fourth child, Alfie, was born three months ago and weighed 8lbs 4ozs – the heaviest of her children.

Public health officials said one of the main causes of the above-average death rate for Leicester was the high number of teen pregnancies.

Teenage mothers are 25 per cent more likely to have a small baby, which is then likely to have more health problems.

High levels of deprivation and overcrowding have also been cited as factors.