Study found alcohol consumption during pregnancy to be relatively high.
The research showed 34 per cent of the 18-to-45-year-olds drank through their last pregnancy, with 24 per cent saying they were likely to drink through their next one too.
Smoking rates were 16 per cent, with just four per cent saying they intended to repeat that in future pregnancies.
"Intention to smoke during a future pregnancy was significantly tied to the intention to consume alcohol," News.com.au quoted Elizabeth Peadon, as writing in the latest Medical Journal of Australia.
"This strong association suggests that strategies aimed at reducing smoking and alcohol consumption during pregnancy should target both behaviours," she added.
Alcohol exposure in utero has been linked to growth retardation, birth defects, and impaired development and neurological function.