Nearly 16 percent of pregnant women in Cumbria and the North East smoke while expecting, new figures have revealed.
The annual figures show a sharp divide between regions: one in four expectant women in Blackpool still smoked by the time their baby was born compared to one in 50 in Westminster.
The national average for smoking during pregnancy fell to 11% of women across England.
But the latest figures show the habit still has a considerable - and in more than 5,000 cases terminal - effect on thousands of pregnancies each year.
The Smoking in Pregnancy Challenge Group has called for the pregnancy smoke rate to be less than 6% by 2020 and the gap to be narrowed between the rich and the poor.
The group, which is a coalition of 20 organisations, also wants better data collection, forced training for health professionals and an automatic referral for pregnant smokers to specialist services unless they opt out.
Here is a percentage breakdown of the number of women smoking at the time of delivery across England's 13 NHS regions during the first medical quarter of 2015/16:
NHS England North (Yorkshire and Humber) - 14.6%
NHS England North (Lancashire and Greater Manchester) - 13.8%
NHS England North (Cumbria and North East) - 15.8%
NHS England North (Cheshire and Merseyside) - 14.0%
NHS England Midlands and East (North Midlands) - 15.0%
NHS England Midlands and East (West Midlands) - 8.9%
NHS England Midlands and East (Central Midlands) - 10.7%
NHS England Midlands and East (East) - 10.1%
NHS England London - 5.0%
NHS England South (South West) - 12.3%
NHS England South (South East) - 10.5%
NHS England South (South Central) - 8.1%
NHS England South (Wessex) - 11.0%
The president of the Royal College of Obstetricians and Gynaecologists (Rcog), one of the pregnancy group's participating organisations, underlined the health problems smoking brings.
A Department of Health spokesman said smoking rates in general and in pregnancy were now at their lowest ever levels.