In Britain, Ireland, Australia and New Zealand, drinking alcohol while pregnant is quite common among women, says new research.
Women across all social strata drank during pregnancy, the findings that appeared online in the journal BMJ Open revealed.
Expectant mothers were significantly more likely to be drinkers if they were also smokers.
"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 percent of pregnancies in the UK and Ireland," the study said.
The research involved 17,244 women who gave birth in Britain, Ireland, Australia and New Zealand.
The researchers found that the prevalence of drinking alcohol ranged from 20 percent to 80 percent in Ireland, and from 40 percent to 80 percent in Britain, Australia, and New Zealand.
A higher level of education, having other children, and being overweight/obese were associated with a lower risk of drinking while pregnant.
But the strongest and most consistent predictor of a heightened risk of drinking alcohol during pregnancy across all three studies was smoking.
The researchers said that most clinical and government guidelines advise women to stop drinking during pregnancy.