DRINKING JUST ONE or two glasses of wine a week while pregnant can influence a child’s IQ, according to a new study by researchers from Oxford and Bristol Universities.
The study, published in PLoS ONE, shows that even moderate alcohol consumption can lead to a reduction in a child’s IQ, if the child has certain genetic variations that affect their ability to break down alcohol.
A spokesperson for Alcohol Action Ireland said their position is that there are “no known safe levels of alcohol during pregnancy” as alcohol crosses the placenta.
A report published by the Department of Health in February this year explored how alcohol exposure can affect the foetus through the occurence of a range of disorders.
The most serious effects are the intellectual disabilities associated with the adverse impact of alcohol on foetal brain development and the central nervous system.
The report said “screening for alcohol consumption should begin at the first antenatal visit for all pregnant women and be reviewed throughout the pregnancy”.
Previous studies from around the world on the effects of moderate alcohol intake on a child’s IQ have produced conflicting results. This may be because it is difficult to separate the effects of moderate drinking from other lifestyle and social factors, such as smoking, diet, affluence, and mother’s age and education.
This study, believed to be the first substantial one of its kind, used genetic variation to investigate the effects of drinking 1–6 units of alcohol per week among a large group of over 4,000 women. Heavy drinkers were not included.
A small, 125ml glass of wine is around 1.5 units while a pint of beer of standard strength is approximately 2 units.
Researchers in the study identified four genetic variations that had an adverse affect on a child’s IQ. The child’s IQ was on average almost two points lower for each variation they possessed.
There was no evidence of this among mothers who abstained during pregnancy, strongly suggesting that the exposure to alcohol in the womb lead to the difference in IQ.
The mothers’ alcohol intake was based on questionnaires completed when they were 18 weeks and 32 weeks pregnant.
The children’s IQ was tested when they were aged eight using a shortened version of the Wechsler Intelligence Scale for Children.