Researchers have released some images, showing a baby grimacing in uterus immediately when the child's mother lights up a cigarette. Durham and Lancaster universities in the UK captured these four-dimensional ultrasound scans as part of a pilot study.

Lancaster University's professor Brian Francis said, "This is yet further evidence of the negative effects of smoking in pregnancy. Technology means we can now see what was previously hidden, revealing how smoking affects the development of the fetus in ways we did not realize".

The preliminary findings of the study stem from an analysis of 80 4-D ultrasound scans of 20 healthy fetuses. Out of these, four were carried by mothers who smoked an average of 14 cigarettes per day, whereas the remaining 16 were carried by nonsmokers.

For the study, researchers took the scans at four different times between 24 and 36 weeks of pregnancy. After the scanning, they observed that maternal smoking was liked to greater fetal mouth and touch movements.

In the study, researchers found that the fetuses displayed higher rates of mouth movement and self-touching as compare to those of non-smokers.

The findings concluded that that the babies of smokers have chances of suffering with delayed development of the central nervous system.

While the ultrasound images have come up as a visual reminder of the harmful effects of smoking on the development of babies, the study results are only preliminary.

Dr Nadja Reissland of Durham University said that a study at larger scale is needed for the confirmation of these results and for the investigation of specific effects, including the interaction of maternal stress and smoking.

The latest study is likely to give smoking pregnant women one more reason to quit their habit of smoking.