When mothers carrying fetuses smoke, the effects can be viewed in the little movements of their fetuses, claim researchers examining high-resolution ultrasound scans. At the onset healthy babies explore their new limbs and body parts—touching their head and face and moving their mouth in a bunch of shapes. Nonetheless, the frequency of these movements slow down as their central nervous system (which controls movement) develop.


Nadja Reissland of Durham University and his team viewed thousands of subtle mouth and touch movements in 80 4D ultrasound scans of 20 fetuses: Out of the 20, four belonged to women who on an average smoke 14 cigarettes a day, whereas the other 16 were carried by non-smokers.

The scans were carried out at four varying intervals between 24 and 36 weeks of pregnancy, and the women as well filled out questionnaires related to stress and depression. In 4D time is the fourth dimension. “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,” study co-author Brian Francis of Lancaster University says in a news release. “This is yet further evidence of the negative effects of smoking in pregnancy.”


Although all babies were born healthy —- the fetuses of smoking mothers showed a markedly higher rate of mouth movements—compared to the normal declining rate of movements expected in a fetus at the time of pregnancy. They also observed evidence of slow down in the reduction of facial touching by fetuses whose mothers smoked. In this expanded chain of movements, the fetus whose mother is a smoker is on top, and a fetus whose mother is a non-smoker is on the bottom:

According to researchers the likely reason for these reactions perhaps is that the central nervous system didn’t develop at the same rate and in the same manner as in fetuses of pregnant mothers who didn’t smoke. “The images suggest that fetuses in smokers are less mature in their behavior,” Reissland tells USA Today. Previous work have pointed to retarded speech processing abilities in infants exposed to smoke prenatally. “Our findings concur with others that stress and depression have a significant impact on fetal movements, and need to be controlled for,” Reissland says in a university statement, “but additionally these results point to the fact that nicotine exposure per se has an effect on fetal development over and above the effects of stress and depression.”

At the start of this month the outcomes of this pilot study were published in Acta Paediatrica. A larger study will need to be done to confirm the results, which could also further examine specific effects.