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Ultrasound Study Reveals How Some Fetuses React to Smoking Moms

Smoking has long been known to cause complications in pregnancy but a new study aims to show how the unborn baby of a smoking mother reacts differently.

A small pilot study published earlier this week in Acta Paediatrica found that fetuses of smoking moms touch their face and mouth much more than fetuses of nonsmoking mothers.

Using high-definition, 4-D ultrasounds, researchers, led by Dr. Nadja Reissland of Durham University in the United Kingdom, investigated minute mouth and hand movements of the fetuses in both the smoking and nonsmoking mothers.

Four out of the 20 pregnancies studied involved mothers who smoked. Each woman had scans at four intervals between their 24th and 36th weeks of pregnancy.

Reissland said fetuses of the smoking mothers had a 58 percent increase of mouth movement and a 69 percent increase in self-touch, where the fetuses touched their face or head, compared to the unborn babies of women who didn’t smoke.

Reissland said previous studies have shown that mothers with high levels of stress are connected to a high level of fetal movements, also causing stress in the unborn baby.

“Fetal facial movement patterns differ significantly between fetuses of mothers who smoked compared to those of mothers who didn’t smoke,” Reissland said, adding that a bigger study is needed to confirm the findings.

“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.”

The extra-movements made by the fetuses of smoking pregnancies could indicate that nicotine or other toxins from the smoke are having an effect on a fetus’ development. Traditionally, Reissland said, the fetus’ movement starts to lessen as they develop to full-term pregnancy.

“The brain…matures indicates certain movements for the fetus that the fetus can make, it’s a proxy for brain development,” said Reissland. “As they grow older, they integrate the movement [and] they make fewer but more complex movements.”

All infants in the study were born at a healthy weight and size with no obvious health issues.

“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 Professor Brian Francis of Lancaster University said. “This is yet further evidence of the negative effects of smoking in pregnancy.”

Reissland says she hopes to follow up with the infants of smoking mothers to see whether they show any new signs of health effects or developmental delays related to their exposure to nicotine in the womb.

Dr. Marjorie Greenfield, a professor of obstetrics and gynecology at University Hospitals Case Western Reserve School of Medicine in Cleveland, was intrigued by the study but said she wants to see more evidence connecting the extra movement in the fetuses to any health effects after birth.

“I think the study is interesting in that it gives us the window to look at the effects of looking at the window on a baby,” Greenfield said. “I think it’s kind of dramatic in that, look, we can see this behavior that’s already different.”

Greenfield said the dramatic images could potentially help discourage other women from smoking during pregnancy, but said she finds the patients who continue to smoke usually have other stressors in their life or other issues that keep them from quitting smoking.

“There isn’t any mom who wants to hurt their kids,” she said. “They feel like they can’t manage without the cigarettes.”

According to the U.S. Centers of Disease Control and Prevention, 10 percent of women reported smoking during the last three months of pregnancy. Smoking during pregnancy has been connected a number of complications, including low birth weight, miscarriage, or premature birth.