Researchers, analyzing 4-D ultrasound of women who smoked while pregnant, determined that fetuses move their mouths and cover their faces when their pregnant moms inhaled cigarettes.

Researchers from Durham and Lancaster Universities in the U.K. analyzed 80 high-definition ultrasound scans of 20 fetuses that were at 24 and 36 weeks of gestation into pregnancy.

Typically, fetuses do move their mouths and touch themselves, HuffPo notes, citing the study, but this movement tends to decline as birth approaches and the fetus gains more control over its motor functions.

“[Ideally], when we show mothers… these videos of fetuses showing increased movement, they will be more inclined to stop smoking,” the study’s lead author Dr. Nadja Reissland of England’s Durham University said in a video by the Press Association, a U.K. media organization. 

Dr. Reissland said she hopes these images will one day be used as educational tools to help expectant mothers make healthier choices.

Even though they know better, about 10 percent of expecting US moms still smoke while pregnant and they do so despite knowing the risks.