Mums-to-be in the north-east are three times more likely to be smokers than those in the south, according to data released by the NHS Information Centre on Wednesday.
Its chief executive Tim Straughan said the findings showed a 'stark' regional divide in England.
Across England, 13.4% of women were smokers at the time of giving birth in October to December 2011. This figure has progressively fallen since 2006/7, when 15.1% were smokers.
But this proportion was considerably higher in every SHA area in the north than in the south.
In the NHS Blackpool area, 30.3% of women were smokers at the time of delivery, more than anywhere else in England.
In contrast, just 2.8% of pregnant women are smokers in NHS Brent, in London.
Mr Straughan said: 'Smoking can cause a range of serious health problems, including lower birth weight, pre-term birth, placental complications and perinatal mortality.
'The statistics we have published today highlight stark regional variation in the proportion of women smoking at the time of giving birth. They will be of considerable interest to those responsible for promoting good health during and after pregnancy.'