The figure is stark contrast to the national average of one woman in ten, according to the study.
The national figure is the lowest since records began nine years ago, when it was recorded at 15.1 per cent.
But in some areas of Yorkshire, the north and Midlands, up to 26 per cent of women in labour wards are recorded as smokers, says the government’s Health and Social Care Information Centre.
Blackpool had the highest prevalence, with 26 per cent women recorded as smokers. London was lowest, London, with 4.9 per cent.