A pilot study by researchers from Durham and Lancaster universities in the UK suggests the harmful effects of smoking during pregnancy may be echoed in the facial movements of unborn infants.

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These ultrasound images at 32 weeks gestation show the increased mouth and facial-touch movements in the fetus of a smoking mother (top), compared with that of a nonsmoking mother (bottom).
Image credit: Durham University

The study, led by Dr. Nadja Reissland of the Department of Psychology at Durham, also found that the effects of stress and depression during pregnancy may be reflected in the facial movements of fetuses, although smoking appears to have a greater impact.

The team reached their findings - published in the journal Acta Paediatricia - by comparing the 4D ultrasound scans of fetuses whose mothers either engaged in smoking during pregnancy or avoided the habit.

The health risks of smoking during pregnancy are well documented. According to the Centers for Disease Control and Prevention (CDC), it can cause tissue damage to the fetus - particularly lung and brain damage - and it has also been associated with cleft lip.

What is more, the CDC state that 1 in 5 babies born to mothers who smoke during pregnancy are born at a low birth weight, which can increase the risk of numerous health problems.

This latest study provides further evidence that nicotine exposure during pregnancy causes harm to the developing fetus, according to the researchers, who say the findings warrant further investigation.

Higher rate of mouth and facial-touch movements identified in fetuses of smoking mothers

The researchers enrolled 20 mothers to the study. Four of these mothers smoked an average of 14 cigarettes a day during pregnancy, while the remaining 16 were nonsmokers.

The mothers underwent four 4D ultrasound scans during 24-36 weeks gestation, providing the team with a total of 80 scans for analysis.

The facial movement patterns of fetuses were assessed using a Poisson log-linear mixed model, and the team found that these patterns differed significantly between smoking and nonsmoking mothers.

Specifically, the researchers found that, compared with the fetuses of nonsmoking mothers, the fetuses of mothers who smoked during pregnancy showed a much higher rate of mouth and facial-touch movements than would normally be expected. Such movements usually decline as pregnancy progresses, but they were persistent across all scans during 24-36 weeks gestation, the team notes.

The researchers also found that fetuses of mothers who experienced stress or depression during pregnancy showed a higher rate of mouth and facial-touch movements, but the association was much stronger in mothers who smoked.

Commenting on these findings, Dr. Reissland says:

"Our findings concur with others that stress and depression have a significant impact on fetal movements, and need to be controlled for, 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.

A larger study is needed to confirm these results and to investigate specific effects, including the interaction of maternal stress and smoking."

In addition, the team says that future studies should investigate how the smoking behavior of fathers during mothers' pregnancy influences the facial movements of fetuses.

Medical News Today recently reported on a study published in the journal Circulation, in which researchers claim children exposed to their parents' smoking are more likely to develop heart disease later in life than children of nonsmoking parents.