Experts are still divided over whether pregnant women should consume alcohol.
The Department of Health did advise expectant mothers in England not to drink "more than one to two units of alcohol once or twice a week".
But both the department and the British Medical Association (BMA) have since changed their stance, and now tell pregnant women to avoid alcohol completely.
Pat O'Brien, a consultant obstetrician at the Institute for Women's Health in London, believes that although fetal alcohol syndrome is clearly a consequence of heavy drinking, there is still no evidence that moderate consumption during pregnancy has any long-term adverse effects.
He makes the claim in a debate in the British Medical Journal (BMJ), and says that telling women to avoid alcohol completely is overly cautious, and is not helped by the fact that people do not understand what one unit of alcohol is.
He argues: "If we in the medical and midwifery professions have failed to communicate clearly to women the meaning of safe limits, then we need to put this right - not take the easy option (for us) and ban alcohol completely."
But Vivienne Nathanson, director of professional activities at the BMA, claims that abstinence is the safest message for women who are pregnant or planning a pregnancy.
And this is especially true given the uncertainty regarding the level of risk to the developing fetus, the lack of clear guidelines, and the confusion about consumption levels, she concludes.