Government research says there is no proven safe limit of consumption
Pregnant women and those trying for a baby should avoid alcohol completely, according to new government advice.
It replaces existing advice that one to two units such as a couple of glasses of wine per week is acceptable.
The change follows concern from some sectors that there is no safe amount of alcohol that mothers-to-be can drink.
While heavy alcohol consumption during pregnancy is known to be damaging to the unborn child, the effects of more moderate intake are less clear.
The Royal College of Obstetricians and Gynaecologists says there is no evidence that a couple of units once or twice a week will do any harm to the baby.
The Department of Health said the revision was not based on new scientific evidence but was needed to help ensure that women did not underestimate the risks to their baby.
It now says pregnant women or women trying to conceive should abstain from alcohol.
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.