Pregnant women have been warned that even half a glass of wine can cause a foetus to stop breathing and moving for as long as two hours.
Professor Peter Hepper of Queen's University in Belfast examined the effects of low-level alcohol exposure during pregnancy by using 18-week scans on women who drank an average of a glass of wine a week.
He found that during the scans, the foetuses stopped breathing and moving, sometimes for up to two hours.
They could suddenly jump and turn themselves over. These jolts suggested that their brains were not developing properly.
His advice is that the "only safe level of alcohol is zero" for pregnant women. This ties in with the advice of the Department of Health.
He said the foetus should be continually active.
It is already accepted that drinking heavily throughout pregnancy can cause a baby to develop a serious condition called foetal alcohol syndrome (FAS).
Children with FAS have restricted growth, facial abnormalities and learning and behavioural disorders.
Drinking alcohol is potentially most harmful for a foetus in the first three months of pregnancy, when it is linked to miscarriage and to birth abnormalities.
Source: Eilish O'Regan, Irish Independent, 09/04/15