More than a third of pregnant women drink alcohol though they are of its harmful effects on the unborn.
A paper, to be presented at the Royal Australasian College of Physicians annual congress in Adelaide on Tuesday, outlines the results of a telephone survey of 1,103 Australian women aged between 18 and 45.
Thirty-four per cent of the women surveyed consumed alcohol during their last pregnancy and 32 per cent said they would drink if planning, and during, a future pregnancy.
Some 93 per cent of survey respondents knew alcohol could affect unborn children and 81 per cent agreed pregnant women should not drink alcohol.
Pediatrician Elizabeth Elliott says alcohol consumption early in pregnancy puts the unborn child at risk of birth defects, while consumption later can impact on the developing brain.
"The message, really, for women should be that no safe level has been established, and that large amounts of alcohol frequently, and particularly early in the pregnancy, is likely to cause the worst outcomes," Professor Elizabeth Elliott told news agency AAP.
"Not drinking in pregnancy is the safest option and we particularly advise women not to become intoxicated."
The alcohol level in the mother's blood is the same as in her foetus.
The risks of alcohol consumption during pregnancy are difficult to predict for each individual because factors such as a woman's weight, age and general health, come into play.
About half of pregnancies are unplanned so inevitably many women have consumed alcohol before learning they are pregnant, Prof Elliott said.
"What we do is reassure women that if they've drunk alcohol at low levels then it's likely that they've done no damage to their baby," she said.
Prof Elliott says Australian attitudes to alcohol are very tolerant.
"So, in contrast to somewhere like the (United) States where if you're a pregnant woman in a pub drinking you might well have people coming up to you and telling you to stop drinking," she said.
"That doesn't happen here as much."
There have been increasing levels of drinking by young women, she said.
Prof Elliott says she hopes revised guidelines on safe drinking, to be issued by the National Health and Medical Research Council later this year, will include messages to women about the dangers of drinking during pregnancy.
She said 95 per cent of women surveyed wanted doctors to ask them about alcohol consumption in pregnancy and to advise them of the potential harm to their foetus.
"The community is ready for a tougher message on alcohol," she said.
"We have got to not only give them (women) the knowledge but we have got to somehow change their attitudes."