Breathing in polluted air during pregnancy has been linked with children having regulatory problems when it comes to their thoughts, emotions, and behaviour, says a new study published in the Journal of Child Psychology and Psychiatry.
Prenatal exposure to an air pollutant called polycyclic aromatic hydrocarbons (PAH) might predispose babies to develop problems in self-regulating behaviours and social competency later in their childhood; poor self-regulating skills are characterised by a difficulty in dealing with disruptive thoughts, emotions, and impulses while poor social incompetency is associated with a restricted ability to gel well with others.
The study, conducted by researchers from the Columbia University’s Mailman School of Public Health, constitutes the first endeavour to have evaluated how children can display problems in self-regulatory capacities as a consequence of exposure to PAH when they were only foetuses resting in their mothers’ bellies.
The researchers used data from 462 mother-child pairs. Blood samples taken from the mothers were tested for DNA-PAH adducts which are an indication of exposure to PAH. Furthermore, child test results were analysed to determine whether the children experienced the behavioural issues; these were used to generate a composite score for the Deficient Emotional Self-Regulation Scale (DESR). Higher scores are related with reduced abilities of self-regulation.
The findings demonstrate that children whose mothers had a greater exposure to PAH during pregnancy scored higher on the DESR at 9 and 11 years of age as opposed to those children whose mothers had lower exposure thereof. Furthermore, children associated with the lower exposure would go through the common pattern of development, and ultimately improved in self-regulatory function while the former group did not — this result shows that early-life exposure to PAH is associated with long-term negative effects. Another finding indicates that the DESR score was also linked with social competence, suggesting that self-regulation has an important role to play in assisting a child to become socially competent.
This study indicates that PAH exposure might be an important factor to be considered when dealing with childhood mental problems. Moreover, reduced self-regulation might also make children more prone to indulging in high-risk behaviour in adolescence.
How does exposure to the air pollutant in question affect the mental capacities of the children? The researchers suggest that PAH might be causing damage to neural circuits that are involved in motor, attentional, and emotional responses.