Maternal Smoking During Pregnancy and Child Well-Being: A Burning Issue

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New findings based on the Growing Up in Ireland study published in the Journal of Abnormal Child Psychology show that children whose mothers smoked during pregnancy have a higher risk of behavioural problems at age 9

The research, conducted by Dr Cathal McCrory (TCD) and Professor Richard Layte (ESRI), is based on data from Growing Up in Ireland – the National Longitudinal Study of Children. A fully copy of the journal article is available to download at A research bulletin which discusses the paper and its implications can be found at Smoking During Pregnancy in Ireland

  • The proportion of mothers who smoke during pregnancy has fallen over time from 28% in the late 1990s to 17.6% currently.
  • Just over a quarter of women (28%) who were smoking in early pregnancy stop at some point before birth.
  • The level of smoking in pregnancy in Ireland is higher than in Northern Europe but lower than in the UK.
  • Women from Eastern and Northern Europe and those with higher levels of education and higher household income are more likely to quit smoking during pregnancy.

The Impact of Smoking During Pregnancy

  • Maternal smoking during pregnancy is strongly associated with low birth weight and perinatal and neonatal complications.
  • Evidence from other countries has also suggested that smoking in pregnancy may be associated with longer lasting problems.
  • Smoking during pregnancy has been associated with an increased risk of childhood behaviour problems in the UK and US, particularly externalising disorders such as conduct problems, attention deficit and hyperactive disorder.
  • Clinical studies have also shown that smoking in pregnancy is associated with an alteration in the pattern of foetal brain development.

New Evidence on the Consequences of Smoking During Pregnancy

  • In Ireland, new longitudinal research based on the Growing Up in Ireland study has revealed that children whose mothers smoked during pregnancy were 1.4 times more likely to be defined as having a behavioural problem by their teacher than children of mothers who did not smoke.
  • The probability of the child being defined as having a behavioural problem increased with maternal smoking. Children whose mothers were occasional smokers were 32% more likely than non-smokers to display behavioural problems. Children whose mothers were heavy smokers (11+ cigarettes a day in pregnancy) were 78% more likely to be defined as having a behavioural problem than the children of non-smokers.
  • Since smoking in pregnancy is strongly associated with low income and deprivation, which are themselves associated with higher levels of behavioural problems in children, this study used an innovative methodological approach to this problem so as to isolate the direct effect of smoking.

Speaking today, one of the report’s authors Dr Cathal McCrory, said:

“It has been known for some time that smoking during pregnancy is associated with premature birth and low birth-weight, but the results of this study show that the effects of smoking during pregnancy are long-lasting and can affect aspects of the child’s emotional and behavioural development in later life. These findings reinforce the need for programs aimed at promoting successful cessation of smoking during what is a critical period for the developing infant.

Growing Up in Ireland is a Government funded study following the progress of almost 20,000 children and their families – a Child Cohort of 8,568 children interviewed at nine years and 13 years of age and an Infant Cohort of 11,134 children participating at nine months and three years of age. The study is being conducted by a consortium of researchers led by the Economic and Social Research Institute (ESRI) and Trinity College Dublin. Those wishing to find out more about the study can visit the study’s website

For further Information please contact:

Dr Cathal McCrory, Trinity College Dublin, + 353 1 8964263,

Notes to Editors:

1. The ESRI Research Bulletin “Maternal Smoking During Pregnancy and Child Well-Being: A Burning Issue”, by Cathal McCrory (TCD) and Richard Layte (ESRI), is available to download on the ESRI website today (12/11/2012). The full Journal Article is available to download at

2. ESRI Research Bulletins provide short summaries of work published by ESRI staff and overviews of thematic areas covered by ESRI programmes of research. Bulletin Articles are designed to be easily accessible to a wide readership. A reference or references to the full publication is included at the end of each Bulletin article.

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