Maternal Smoking Before Childbirth Has Long-Term Effects on Children's Neurodevelopment, Including Intellectual Disability and ADHD

A Nationwide Cohort Study of 860,000 Korean Mother-Child Pairs
Former Smoking History and Even Low Levels of Smoking Raise Risks

A large-scale study has found that maternal smoking before childbirth can have long-term effects on the neurodevelopment of offspring. In particular, the study confirmed that even a past history of smoking increases the risk of neurodevelopmental disorders in children, and that relatively low levels of smoking can also have an impact.

(From left) Moonyoung Jang, Professor of Psychiatry at Korea University Guro Hospital; Junbin Park, Professor of Cardiology at Seoul National University Hospital; Kyungdo Han, Professor of Information Statistics and Actuarial Science at Soongsil University; Jaewon Kim, Professor of Child and Adolescent Psychiatry at Seoul National University Hospital.

Moonyoung Jang, Professor of Psychiatry at Korea University Guro Hospital, along with Junbin Park, Professor of Cardiology at Seoul National University Hospital, Kyungdo Han, Professor of Information Statistics and Actuarial Science at Soongsil University, and Jaewon Kim, Professor of Child and Adolescent Psychiatry at Seoul National University Hospital, jointly analyzed data from 861,876 mother-child pairs who met the study criteria among infants born between 2009 and 2018. They conducted a nationwide, population-based mother-child cohort study, the results of which were released on March 24.

Maternal smoking status was classified as non-smoking, former smoking, or current smoking (at the time of the health screening), using data from routine health checkups by the National Health Insurance Service conducted within two years before childbirth. The children were followed for an average of more than eight years, up to 2021, to determine whether they were diagnosed with intellectual disability, autism spectrum disorder (ASD), or attention-deficit/hyperactivity disorder (ADHD).

The results showed that children of mothers with a history of smoking had a significantly higher cumulative incidence of all neurodevelopmental disorders compared to children of non-smoking mothers. Compared to children in the non-smoking group, children in the former smoking group had a cumulative incidence rate that was 21% higher for intellectual disability, 29% higher for autism spectrum disorder, and 18% higher for attention-deficit/hyperactivity disorder. For children in the current smoking group, the rates were 44% higher for intellectual disability, 52% higher for autism spectrum disorder, and 35% higher for attention-deficit/hyperactivity disorder.

Analysis of the effects according to smoking quantity showed that, among current smokers, the risk of neurodevelopmental disorders increased in proportion to the amount smoked. Even in the group with the lowest smoking exposure (pack-years less than 1.75), the cumulative incidence rates were 35% higher for intellectual disability, 55% higher for autism spectrum disorder, and 33% higher for attention-deficit/hyperactivity disorder, indicating increased risks.

*Cumulative incidence rate difference of neurodevelopmental disorders between children of mothers with a history of smoking and children of non-smoking mothers.*

Professor Jang commented, "This study is significant because it confirmed the association between maternal smoking and neurodevelopmental disorders in children using the largest mother-child cohort in Korea. In particular, the findings show that even a minor past history of smoking can impact a child's neurodevelopment, highlighting the importance of quitting smoking even before pregnancy." Professor Jang also stated, "From a public health perspective, this study suggests that social and medical support systems are needed to reduce smoking among women of childbearing age."

The research paper detailing these findings, entitled "Association between maternal smoking and risk of neurodevelopmental disorders in offspring using prenatal health checkup data: A Korean mother-child cohort study," was published in the latest issue of the international journal BMC Medicine.

This content was produced with the assistance of AI translation services.