In-utero exposure to tobacco derails normal neurocognitive development

Prenatal exposure to tobacco disrupts normal neurocognitive development independently of preterm delivery or low birth weight, a recent study has found.

Drawing from the Healthy Start study, researchers followed 647 mother-child dyads through 6 years of age. Tobacco exposure was determined through maternal urinary cotinine assessments at 27 weeks of gestation. The National Institutes of Health (NIH) Toolbox Cognition Battery and the Third Edition Ages and Stages questionnaire (ASQ-3) were used to evaluate neurocognitive status in the offspring.

Compared to infants who had no prenatal exposure of tobacco, the risk of failing the ASQ-3 was 3.9 times (95 percent confidence interval [CI], 1.5–10.3) greater in those with such exposures. This effect was driven primarily by the effect of tobacco on fine motor skills, which remained statistically significant even after adjusting for postnatal exposures (adjusted odds ratio [OR], 3.3, 95 percent CI, 1.1–10.2).

No such relationship was found between maternal urinary cotinine and other ASQ-3 domains, including gross motor, personal-social, communication and problem-solving skills.

In terms of NIH Toolbox outcomes, researchers found that those with prenatal exposure to tobacco had significantly poorer inhibitory control, though this did not persist after adjustments for postnatal exposures. On the other hand, cognitive flexibility and receptive language were unrelated to prenatal tobacco exposure.

“The results of our study, coupled with recent trends in smoking prevalence and market shifts to different nicotine products, suggest that it is important to encourage parents to quit smoking and limit their children’s exposure to nicotine and tobacco during and after pregnancy,” the researchers said.