Most people know that drinking too much while pregnant is bad for the baby, but a new study shows even moderate drinking can affect a child's IQ.
Researchers from the Universities of Bristol and Oxford took data from 4,000 mothers and their children. They then tested certain genetic variations in children to see how their mothers drinking had affected them.
Children of mothers who had consumed a moderate amount of alcohol (between 1 and 6 units a week) were more likely to have one of more of four specific genetic variations. On average, the child was two IQ points lower for each of the four genetic modifications they possessed.
“Our results suggest that even at levels of alcohol consumption which are normally considered to be harmless, we can detect differences in childhood IQ, which are dependent on the ability of the foetus to clear this alcohol. This is evidence that even at these moderate levels, alcohol is influencing foetal brain development,” said the report's main author, Dr. Sarah Lewis.
This is the first large scale test of its kind to eliminates lifestyle factors and examines just the effects of alcohol on IQ. Most other tests are not able to remove the effects of things like the mothers IQ, diet, smoking habits and other factors, but this new test is different. By looking at only the genes of mother and child all lifestyle factors are automatically ruled out.
'This is a complex study but the message is simple: even moderate amounts of alcohol during pregnancy can have an effect on future child intelligence. So women have good reason to choose to avoid alcohol when pregnant.' Said Dr. Ron Gray, lead researcher from the University of Oxford.
This contradicts previous studies that have shown moderate drinking may even be beneficial during pregnancy. The researchers believe these past studies are flawed because they did not take into account many lifestyle factors. The most important of these is the implications of moderate drinking.
Unlike heavy drinkers who are more likely to have lower IQ’s and less education, moderate drinkers are often highly educated, do not smoke and have a healthy diet. This can skew the results of some studies and may explain why they found moderate amounts of alcohol were beneficial for pregnant women.
Currently the US and the UK both recommend women completely avoid drinking alcohol during their pregnancy. They both stress that this is particularly important in the first three months of pregnancy but there is no guarantee that consuming even a small amount of alcohol during pregnancy is safe at any time.