Children whose mothers had drank one to two drinks a week during pregnancy were discovered to not be at increased risk of behavioural difficulties or cognitive deficits.
How was the issue examined?
A team from University College London used longitudinal data from infants born in the UK between 2000 and 2002.
Mothers were asked about their drinking habits during pregnancy.
They were divided into those who never drank, those who usually drank (but who did not do so while pregnant) and those who drank one to two units a week, two to six units a week or more than six units a week
Children were followed up through home visits involving cognitive assessments and questions about behaviour, socioeconomic factors and the family environment.
Are the results valid?
The children of light drinkers performed better on average in cognitive tests, including naming vocabulary, picture similarities, and pattern construction.
However, there were socioeconomic differences between the groups. Light drinkers had a higher family income, and were more likely to be degree-educated.
Lead researcher Dr Yvonne Kelly acknowledged the differences between the groups. She said: 'We took it into account and the results held across all measures.'
But the strength of the effect observed was reduced when these factors were taken into account.
What is the current guidance?
The current advice for pregnant women and women trying to conceive is that, as a general rule, they should avoid drinking alcohol, a DoH spokeswoman said.
'If they do choose to drink, to minimise the risk to the baby, they should not drink more than one to two units of alcohol once or twice a week and should not get drunk,' she added.
However, the DoH has been criticised in the past for offering conflicting advice, and Dr Kelly argues that the second part of its guidance contradicts the first.