Research has revealed that women in the north of England are up to nine times more likely to smoke during pregnancy than those in the south of the country.
Figures compiled by the Association of Public Health Observatories (APHO) showed that one in three women in Blackpool, Lancashire, smoked while pregnant, in contrast to just 4% in Richmond, Surrey. Looking at the country as a whole, almost 15% of women said they had smoked during pregnancy.
London Health Observatory director, Dr Bobbie Jacobson, said: "The significant proportion of women who reported smoking in pregnancy is a sign of our need to redouble our preventative efforts in primary and maternity care."
She called on local authorities and partnerships between the NHS and general practitioners to address the problem.
The APHO survey also found there were 207 smoking-related deaths per 100,000 people aged 35 and over in England during 2006-08. This was down from 216 deaths per 100,000 in 2004-06.
Smoking related deaths from lung cancer were highest in Middlesbrough, with the illness claiming 71 victims per 100,000 in 2006-08. This compared with 19 per 100,000 smokers dying from lung cancer in Guildford in the same period.
"There is clearly a mix of good and bad news," Dr Jacobson said.
"The overall picture of falling death rates is encouraging and shows what can be achieved over time through clear plans to tackle the harm from smoking."
But, she added "the North/South inequalities remain a stark reminder that the biggest burden of smoking-related ill health still falls on our poorest communities."
The survey was commissioned by the Department of Health, on behalf of APHO.