This is according to new research undertaken at the James Cook University Hospital in Middlesbrough. It is hoped that the research can be used to encourage more mothers to give up the habit while pregnant.
 
Dr Nadja Reissland  studied the moving 4D ultrasound scans of 20 pregnant women who were at various stages of pregnancy; 24, 28, 32 and 36 weeks.

Her study found that the unborn babies of the four smoking mothers showed significantly higher rates of touching themselves and moving their mouths more frequently than those carried by non-smokers. Foetuses usually move their mouths and touch themselves as they develop and gain control over their limbs. Dr Reissland’s indicates that mothers who smoke may delay the development of their babies’ central nervous systems. 

 “A larger study is needed to confirm these results and to investigate specific effects, including the interaction of maternal stress and smoking,” she said.

Dr Reissland, who specialises in foetal development, asked for women to be offered more assistance in giving up, rather than demonising those mothers who smoke. "I'm really grateful, they did a good thing," she said. "These are special people and they overcame the stigma to help others."

Thankfully all of the babies studied were born healthy and of normal weight and size.