Scientists at Durham and Lancaster Universities in the U.K. said they have found that the harmful effects of smoking during pregnancy may be reflected in the facial movements of mothers' unborn babies. Observing 4D ultrasound scans, the researchers discovered that 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.
The team suggested that the reason for this might be that the fetal central nervous system, which controls movements in general and facial movements in particular, did not develop at the same rate and in the same manner as in fetuses of mothers who did not smoke during pregnancy. Previous studies have reported a delay in relation to speech processing abilities in infants exposed to smoking during pregnancy, the researchers added.
The researchers observed 80 4D ultrasound scans of 20 fetuses, to assess subtle mouth and touch movements. Scans were taken at four different intervals between 24 and 36 weeks of pregnancy. Four of the fetuses belonged to mothers who smoked an average of 14 cigarettes per day, while the remaining 16 fetuses were being carried by mothers who were nonsmokers. All fetuses were clinically assessed and were healthy when born.
In common with other studies, the research also showed that maternal stress and depression have a significant impact on fetal movements, but that the increase in mouth and touch movements was even higher in babies whose mothers smoked.
The study (“Ultrasound observations of subtle movements: a pilot study comparing fetuses of smoking and non-smoking mothers”), published in Acta Paediatrica, also found some evidence of a bigger delay in the reduction of facial touching by fetuses whose mothers smoked, compared to the fetuses of nonsmokers, but the researchers said this delay was less significant.
“A larger study is needed to confirm these results and to investigate specific effects, including the interaction of maternal stress and smoking,” wrote the investigators. “Additionally, the feasibility of this technique for clinical practice should be assessed.”
According to Brian Francis, Ph.D., of Lancaster University, “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. This is yet further evidence of the negative effects of smoking in pregnancy.”
The research team added that future studies should also take into account the smoking behaviors of fathers.