The latest statistics published by the Health and Social Care Information Centre show that in 2015/16, 14.5 per cent of women giving birth in Yorkshire smoked. That figure amounted to 9,071 of the 62,735 pregnancies during the period.
Across the region, there were vast differences in the number of women who smoked at the time they gave birth.
The highest prevalence was in North East Lincolnshire, where almost a quarter, 23.5 per cent of women smoked at birth.
That was followed by the Hull clinical commission group (CCG) area, where 777 women said they were smoking at the time they went into labour - 21.1 per cent.
The lowest prevalence was in Leeds North, where 6.6 per cent of women giving birth were smokers.
According to the NHS, the risks of smoking during pregnancy range from premature delivery to increased risk of miscarriage, stillbirth or sudden infant death.
The data also compared smoking rates to the previous year, and found the biggest improvement to be in Doncaster, where rates had dropped 7.6 per cent compared to 2014/15. There, the percentage of women smoking when they gave birth stood slightly below the Yorkshire average at 12.9 per cent.
Doncaster Council’s cabinet member for public health and well-being, Coun Pat Knight, said the fall was “very encouraging”.
Coun Knight added: “There are well documented health benefits for mum and baby for not smoking during pregnancy and we urge more would be mums to use pregnancy as the perfect reason to quit smoking.”
The highest increases were seen in two North Yorkshire CCG areas, Harrogate and Rural District, and Hambleton, Richmondshire and Whitby, which recorded 4.1 per cent and 2.8 per cent increases respectively. Both though fell slightly below the Yorkshire averages, at 12.2 per cent and 14.1 per cent - despite the high increases year-on year.
Elsewhere in North Yorkshire, Scarborough registered the fourth highest percentage for 2015/16, with almost one in five women smoking full-term - 19 per cent.
A spokesperson for the North Yorkshire Public Health Team said it had been working hard with partners to reduce rates across the county, especially in Scarborough and Ryedale where smoking at time of delivery rates are highest.
She added: “We are concerned about the increase of 4.1 per cent between last year and this in Harrogate and Rural district. However despite this increase the prevalence remains the lowest across the county.”
In Hull, the local authority recognised that both smoking in pregnancy rates, and general smoking rates, were higher than the national average.
Hull Council has re-designed its stop smoking service to target particular groups, including pregnant women.
City manager for health and wellbeing, Tim Fielding, said: “Although smoking in pregnancy rates have fallen significantly over the last five years from over 23 per cent in 2010/11, they are still too high. Reducing smoking rates in Hull will not happen overnight, however we are committed to inspiring a smoke-free generation by 2025.”