A recent Australian study has found that 18 percent of women smoked and 38 percent of women drank alcohol while expecting.
The study, conducted by the Australian Institute of Family Studies, drew data from Growing Up in Australia: The Longitudinal Study of Australian Children (LSAC), which has tracked the progress of more than 10,000 children since 2004.
Dr. Ben Edwards, LSAC manager at the Australian Institute of Family Studies, said alcohol consumption and cigarette smoking were related to the age of the mother, with younger mothers more likely to report smoking and older mothers more likely to report drinking alcohol during pregnancy.
The study found that nearly 20 percent of mothers under 25 years old drank alcohol and 37 percent smoked cigarettes during their pregnancy.
Around 44 percent of mothers aged 30 and over drank alcohol and early 10 percent smoked cigarettes during pregnancy.
The study also found that women living in regional areas were more likely to report smoking at some stage during pregnancy than women in metropolitan areas.
Financial background also played a part in whether mothers took prescription medicines and smoked cigarettes.
Mothers from a poorer socio-economic background were more likely to take prescription medicines and less likely to take over-the-counter medications during pregnancy. They were also more likely to smoke, have high blood pressure and stress, anxiety or depression during pregnancy and their children were more likely to be born pre-term, and to have a low birth weight.
At the other end of spectrum, mothers from the top 25 percent of socio-economic position were more likely to report drinking alcohol at some stage during pregnancy, compared to other mothers.
Dr. Edwards said changes in public health warnings about alcohol may have caused confusion among pregnant women about how much alcohol is safe.