The number of pregnant smokers has dropped to the lowest recorded level in England, the latest figures show.
Just 12% of women smoked during pregnancy, the figures for 2013/14 show.
However, there was wide regional variation, with just 5% of pregnant women smoking in London, compared to 21% in Durham.
Since 2006/07 the number of women who smoked while pregnant fell by 16%, and overall maternities have increased by 5%, the Health and Social Care Information Centre (HSCIC) figures show.
Government targets to reduce rates of smoking throughout pregnancy to lower than 11% by 2015 have not yet been reached.
Around 40% of local authority areas have yet to reach the target.
HSCIC chair Kingsley Manning said: “It is encouraging to see that since 2006-07 the number of pregnant women who smoked during pregnancy has declined. However, there is still a little way to go to achieve the national ambition.
“Today’s figures highlight there is a still work to be done and it is fundamental that mothers-to-be are aware of the damaging effects smoking can have on their baby.”