Carried out by the Australian Institute of Family Studies, it uses data from Growing Up in Australia: The Longitudinal Study of Australian Children, which has tracked more than 10,000 children since 2004.
The institute’s LSAC manager, Ben Edwards, said alcohol consumption and cigarette smoking were related to the age of the mother and women were not heeding health warnings.
“The early childhood health experiences of these newborns and young children varied depending on where their families live, the age of their mother and whether their parents are well off or struggling financially,” Dr Edwards said.
The study shows younger mothers are more likely to smoke while older mothers are more likely to drink during pregnancy.
It shows almost 20 per cent of pregnant women under 25 years old drank alcohol and 37 per cent smoked cigarettes.
About 44 per cent of pregnant women aged 30 and over drank alcohol and about 10 per cent smoked cigarettes.
There was no figure on how much alcohol they were drinking.
Dr Edwards said the study showed that women who were smokers needed much more support to quit.
He said the study also found women living in regional areas were more likely to report smoking at some stage during pregnancy.
“Younger mothers were more likely to smoke but were less likely to take over-the-counter medications and less likely to drink alcohol at some stage during pregnancy,” Dr Edwards said.
“Older mothers were more likely to experience diabetes during their pregnancy, to drink alcohol at some stage during pregnancy, but were less likely to smoke.”
Dr Edwards said changes in public health warnings about alcohol might have caused confusion among pregnant women about how much alcohol was safe.