Light drinking in pregnancy not bad for children, says UCL study

31 October 2008

Children born to mothers who drink lightly during pregnancy – as defined as 1–2 units per week or per occasion – are not at increased risk of behavioural difficulties or cognitive deficits compared with children of abstinent mothers, according to a new study led by researchers at UCL.

The research, based on data from the UK Millennium Cohort Study, is published today in the ‘International Journal of Epidemiology’. It uses data on 12,495 three year-old children, looking at the mothers’ drinking patterns during pregnancy and assessments of the behavioural and cognitive outcomes of their children.

Lead author Dr Yvonne Kelly (UCL Epidemiology & Public Health) said: “The link between heavy drinking during pregnancy and consequent poor behavioural and cognitive outcomes in children is well established. However, very few studies have considered whether light drinking in pregnancy is a risk for behavioural and cognitive problems in children.

“Our research has found that light drinking by pregnant mothers does not increase the risk of behavioural difficulties or cognitive deficits. Indeed, for some behavioural and cognitive outcomes, children born to light drinkers were less likely to have problems compared to children of abstinent mothers, although children born to heavy drinkers were more likely to have problems compared to children of mothers who drank nothing whilst pregnant.”

The study data shows that boys born to mothers who drank lightly were 40 per cent less likely to have ‘conduct’ problems and 30 per cent less likely to have hyperactivity, even when a range of family and socioeconomic factors were taken into account. Boys born to light drinkers also had higher scores on tests of vocabulary and whether they could identify colours, shapes, letters and numbers compared to those born to abstainers.

Girls born to light drinkers were 30 per cent less likely to have emotional symptoms and peer problems compared with those born to abstainers, although this appeared partially explained by family and social backgrounds.

Dr Kelly continued: “The reasons behind these findings might in part be because light drinkers tend to be more socially advantaged than abstainers, rather than being due to the physical benefits of low level alcohol consumption seen, for example, in heart disease. However, it may also be that light-drinking mothers tend to be more relaxed themselves and this contributes to better behavioural and cognitive outcomes in their children.”

The UK currently does not recommend complete abstinence from alcohol for the duration of pregnancy and there are inconsistencies in policy statements from the National Alcohol Strategy and the National Institute for Health and Clinical Evidence (NICE), which may cause confusion for health professionals and the public.

A recent review carried out by the National Perinatal Epidemiology Unit, and a statement from the Royal College of Obstetricians and Gynaecologists highlighted the need for studies focusing on the effects of light drinking, and for investigators to use population-based data, as the researchers have done in this study.

Dr Kelly added: “There is inconsistency in policy around this issue and studies such as this one are vital in light of the wider debate around drinking and pregnancy. Our study's findings do raise questions as to whether the current push for policy to recommend complete abstinence during pregnancy is merited and suggest that further research needs to be done.”

To read the paper in full, or to find out more about Dr Kelly and UCL Epidemiology & Public Health, use the links at the top of the article.