Prenatal exposure to smoking could increase the risk for attention-deficit/hyperactivity disorder in children, according to recent study findings published in Pediatrics.

Jin Liang Zhu, PhD, of the University of Aarhus in Denmark, and colleagues evaluated a cohort of 84,803 singleton births and their parents’ smoking habits to determine the association of parental smoking in pregnancy and ADHD. Children were followed up for 8-14 years.

At follow-up, 2.4% of participants were diagnosed with ADHD or received an ADHD medication.

“Pregnant women should, with psychosocial support, be encouraged to quit smoking preferably without the use of nicotine replacement,” Zhu told “Although more studies are needed to determine to what extent the link between maternal tobacco smoking and offspring ADHD is causal, the consistent association should lead clinicians to awareness of possible ADHD symptoms in children born to smoking mothers.”

Parental smoking, overall, was linked to a higher risk for ADHD diagnosis or medication, but maternal smoking had a greater risk than paternal smoking. Participants with smoking mothers and nonsmoking fathers were at increased risk for ADHD compared with participants whose parents did not smoke (HR=1.63; 95% CI, 1.36-1.94).

Similarly, participants with nonsmoking mothers but smoking fathers had a higher risk compared with participants with nonsmoking parents (HR=1.29; 95% CI, 1.14-1.47).
Participants also had a higher risk for ADHD if their mothers used nicotine replacement during pregnancy.