A survey of more than 120,000 pregnant women over the past 20 years suggests that more than 60% of them consumed alcohol while they were expecting.
The research, conducted by the Coombe Women's Hospital in Dublin, also indicates that more than 45% of the women surveyed in 2005 continued to smoke during pregnancy.
While the use of illicit drugs during pregnancy was far more infrequent, nearly 5% of respondents used some form of drug.
In response to the report Dr Siobhán Barry, lead researcher on the study, said the findings show that alcohol consumption patterns in pregnancy give particular cause for concern.
'More efforts are required to enable pregnant women and women who are contemplating pregnancy to make healthier choices,' she said.
Further evidence from the study also shows that the highest rates of low birth weight are in heavy smokers and users of illicit drugs.
Dr Barry believes that some of the results of the study are 'so striking that they cannot be ignored'.
Master of the Coombe Women's Hospital, Dr Chris Fitzpatrick, said the study has provided 'prima facie evidence that we need to take the issue of alcohol in pregnancy far more seriously'.
The report, which is the first of its kind in Ireland, also highlights the importance of conducting research in the area in order to protect the next generation of Irish children, he added.
