Study: Smoking mothers delay babies' development

A pregnant woman who smokes may delay her unborn baby’s central nervous system development, according to new research published in the medical journal Acta Paediatrica.

Researchers at Durham and Lancaster universities in Great Britain studied 4D ultrasounds of 20 infants at 24, 28, 32, and 36 weeks gestation. Sixteen of the mothers didn’t smoke during pregnancy while four smoked 14 cigarettes per day on average. Infants whose mothers smoked showed signs of delayed neurological development.

As pregnancies progress and infants gain more physical control, they display fewer mouth movements and touch their faces less. But babies with smoking mothers demonstrated a significantly higher amount of those movements compared to the typical decline associated with healthy development, the study found. The researchers believe the high amount of movements may indicate delayed central nervous system development.

“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 Brian Francis, a statistician at Lancaster University, said in a news release. “This is yet further evidence of the negative effects of smoking in pregnancy.”

Other studies have reported delayed speech development for infants whose mothers smoked during pregnancy. And smoking during pregnancy is already associated with premature births, miscarriages, early placenta separation from the womb, Sudden Infant Death Syndrome, and cleft lips and palettes. The Centers for Disease Control and Prevention reports 10 percent of women in 2011 said they smoked during the last 3 months of pregnancy. And the American Pregnancy Association says about 1,000 babies die annually due to mothers’ smoking habits.

The study also found maternal stress and depression affect infant neurological development. But the delay was even greater for infants whose mothers smoked.

Lead researcher Nadja Reissland noted the research is only a pilot study, and the issue requires further investigation into the relationship between fetal development and maternal stress, smoking, and depression. The impact of paternal smoking also needs to be examined.

“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,” Reissland said. “A larger study is needed to confirm these results and to investigate specific effects.”