Now researchers believe they can show the effects of smoking on babies in the womb using 4D ultrasound scans – and use the images to encourage mothers who are struggling to give up. Dr Nadja Reissland has studied moving 4D scan images and recorded thousands of tiny movements in the womb. Her study, conducted at the James Cook University Hospital in Middlesbrough.

Dr Nadja Reissland scanned babies between weeks 24 and 36 of pregnancy, and showed that babies carried by women who smoked appeared to move their mouths and touch their faces more than non-smokers’ babies.

Dr Reissland’s results – which she hopes to replicate across a far larger sample size – 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,” Dr Reissland said.

It is hoped that the research can be used to encourage more mothers to give up the habit while pregnant. But Reissland was against demonising mothers and called for more support for them to give up. Currently, 12% of pregnant women in the UK smoke but the rate is over 20% in the Durham, Darlington and Tees area.

Dr Reissland, who has an expertise in studying foetal development, thanked the mothers who took part in her study. All the babies in her study were born healthy, and were of normal size and weight.