Most of us know that smoking during pregnancy can result in a host of problems for both the mother and the fetus, but new astonishing research indicates that these harmful effects can be written on the faces of these unborn babies themselves.

That's at least according to a new study published in the journal Acta Paediatrica, which found that fetuses whose mothers were smokers showed more facial movements - specifically in their mouths - than what researchers would normally expect to see during pregnancy.

A team at Durham and Lancaster universities suggests that smoking alters the development of the fetal central nervous system, which controls movements in general and facial movements in particular. This theory goes along with previous research that has reported a link between smoking during pregnancy and a delay in relation to speech processing abilities in infants.

In order to better understand the negative effects of smoking while pregnant, the researchers observed 80 4-d ultrasound scans of 20 fetuses and assessed 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 non-smokers.

It should be noted that all of the unborn children studied were clinically determined to be healthy when they were born.

What they found was 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. They also realized that maternal stress and depression have a significant impact on fetal movements - however, smoking caused even more mouth and touch movements in comparison.

"Fetal facial movement patterns differ significantly between fetuses of mothers who smoked compared to those of mothers who didn't smoke," lead author Dr. Nadja Reissland from Durham University said in a statement. "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."

While future research on a larger scale needs to be done to confirm these findings, they certainly add weight to existing evidence that smoking is harmful to unborn babies as they develop in the womb.

According to the Centers for Disease Control and Prevention (CDC), smoking during pregnancy can lead to various health problems due to a lack of oxygen to the fetus. This includes premature birth, certain birth defects - such as cleft lip or cleft palate - and infant death. Women who smoke during pregnancy are also more likely than other women to have a miscarriage.

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