Drinking alcohol during pregnancy is very common in Ireland and women are much more likely to drink while pregnant if they smoke, a new study has found.

UK researchers carried out of a study of almost 18,000 women in four countries - Ireland, the UK, Australia and New Zealand. They found that drinking before and during pregnancy was common in all four countries, however Ireland had the highest rates.

Based on estimates, 90% of women in Ireland drink alcohol before pregnancy, while 82% drink during pregnancy. Ireland also had the highest rate of binge drinking before pregnancy (59%) and during pregnancy (45%).

However, the researchers warned that the exact prevalence in Ireland could be much lower as findings from the Growing Up in Ireland (GUI) study estimated that between 20% and 46% of women consumed alcohol during pregnancy.

The prevalence of drinking alcohol during pregnancy in the UK, Australia and New Zealand ranged between 20% and 80%.

The study noted a number of factors that were associated with drinking during pregnancy in all four countries. White women were more likely to drink than those of other ethnicities. Women aged 40 and older were also more likely to drink than those aged 30-39.

Women with a higher level of education, those with other children, and those who were overweight or obese were less likely to drink during pregnancy.

However overall, women were much more likely to drink during pregnancy if they were smokers. In fact, smokers were up to 50% more likely to drink during pregnancy.

The researchers emphasised that most of the women who did drink during pregnancy only consumed low levels of alcohol. However, they pointed out that since the risks of low levels of drinking are not fully understood, women should avoid alcohol during pregnancy.

"Alcohol use during pregnancy is highly prevalent, and evidence from this cross-cohort and cross-country comparison shows that gestational alcohol exposure may occur in over 75% of pregnancies in the UK and Ireland.

"Since most women who consume alcohol do so at lower levels where the offspring growth and development effects are less well understood (than at higher levels), the widespread consumption of even low levels of alcohol during pregnancy is a significant public health concern," the team from the University of Cambridge concluded.

Details of these findings are published in the journal, BMJ Open.

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