Air pollution and stress during pregnancy linked to children's behavioural problems

Air pollution and psychological stress during pregnancy can be detrimental to a child's behaviour, according to research. A new study performed by the Columbia Center for Children's Environmental Health at the Mailman School of Public Health has found that the combination of exposure to air pollution and maternal psychological distress can affect the way that a child's behaviour develops later in life.

Maternal demoralisation, which is a type of psychological stress that affects how a pregnant woman is able to cope in stressful situations, has been linked to several types of behavioural problems in children. Children that are subjected to this condition whilst within the womb often develop behavioural problems, such as depression, anxiety, externalising problems, attention or aggressive behavior, later on in life. 

The study found that the effects of maternal demoralisation were more likely experienced by children whose mothers had been exposed to high levels of polycyclic aromatic hydrocarbons (PAH) during pregnancy. PAH air pollution is generally produced by the combustion of fossil fuels, such as that which happens at coal-fired plants and in motor vehicles' engines. They can also be created by tobacco smoke and indoor heating.

Doctor Frederica Perera, director of the Center, said: "This study shows that the combination of physical and psychosocial stressors during fetal development magnifies the effect of each exposure. The findings are of concern because attention problems and anxiety and depression have been shown to affect peer relationships, academic performance, and future well-being of children."     

The study, which took place in Krakow, Poland, followed 248 mother-child pairs throughout pregnancy and up until the child turned nine. Sampling of air quality took place during pregnancy to assess the levels of PAH that each woman was subject to. As the child grew, their behaviour was assessed through the Child Behavior Checklist, which saw the mothers answer a set of questions on the behaviour of their child. The extent of maternal demoralisation was assessed through a number of socioeconomic factors and a questionnaire during the third trimester of pregnancy.