Research from Durham and Lancaster universities have shown the harmful effects of smoking on unborn babies. The researchers said that pregnant women who smoke may have babies who witness delayed development of the central nervous system.

The researchers have captured 4-D ultrasound scans, which unveiled movements of baby when their mothers inhale cigarette smoke. The scans show how babies in the womb open their mouths and cover their faces.

In fact, it also appears that they frown when they mothers inhale cigarette smoke. The researchers said, "Fetuses whose mothers were smokers showed a significantly higher rate of mouth movements than the normal declining rate of movements expected in a fetus during pregnancy".

Study's co-author Professor Brian Francis said that more research will be needed to confirm the results. He has thanked the technology that allowed him to see what they were not able to in the past. They came to know that smoking affects development of the fetus in the ways that they do not think.

The research acts as yet another proof of the negative effects of smoking in pregnancy. The researchers said that those women who did not smoke showed a normal developmental process in comparison to those women who smoke.

Earlier studies have also explained that exposure of cigarette smoke in the womb is linked to delayed speech development in infants. For the current study, the researchers have conducted an analysis of 80 4-D ultrasound scans of 20 healthy fetuses.

Four of them were carried out by mothers who smoked an average of 14 cigarettes per day and the remaining 16 were carried by non-smokers. The researchers have taken the scans four differnet times between 24 and 36 weeks of pregnancy.

The researchers realized that maternal smoking was associated with greater fetal mouth and touch movements.