Women in the North East are more than three times more likely to be smokers at the time they give birth as those in London, figures show.
Data from the NHS Information Centre revealed 20.2 per cent of women in the North East were smokers when they gave birth, compared with 6.1 per cent in London.
Across England, 13.4 per cent of women are smokers at the time of delivery, down from 15.1 per cent in 2006/07.
The percentages varied widely by region, from 2.8 per cent in Brent, London, to 30.3 per cent in Blackpool.
Nevertheless, the data showed smoking rates were “considerably higher” in every northern strategic health authority than in the south.
NHS Information Centre chief executive Tim Straughan said: “Smoking can cause a range of serious health problems, including lower birthweight, pre-term birth, placental complications and perinatal mortality.
“The statistics we have published 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.”
Royal College of Midwives (RCM) deputy general secretary Louise Silverton said the figures were “alarming”.
She said: “The north-south divide revealed in these statistics highlights the gaping health inequalities in access to appropriate public health services.
Public Health Minister Anne Milton said: “The regional variation we are seeing here is unacceptable and we want to reduce rates of smoking throughout pregnancy across all areas of the country.
“NHS doctors, nurses and midwives are working hard with their local communities to tackle this.”