Gestational diabetes mellitus (GDM) is a form of diabetes diagnosed during pregnancy that lasts the duration of the pregnancy.
Women with GDM are at increased risk of developing Type 2 diabetes and their babies are more likely to have a high birth weight and suffer birth trauma.
The report, Gestational diabetes mellitus in Australia, 2005-06, showed that in 2005-06, 4.6 per cent of women aged 15-49 years who gave birth in hospital were diagnosed with GDM.
'This amounts to more than 12,400 women and their babies affected,' said Mardi Templeton of the Institute's Cardiovascular, Diabetes and Kidney Unit.
The report found the incidence of gestational diabetes among all Australian women in the 15-49 year age bracket increased by over 20 per cent between 2000-01 and 2005-06.
The risk of being diagnosed with gestational diabetes increases with age - from 1 per cent among 15-19 year old women to 13 per cent among women 44-49 years of age.
'As would be expected, the age group that has the most babies (women aged 30-34 years) accounted for over 30 per cent of GDM cases in 2005-06,' she said.
'Women born overseas are at greatest risk of being diagnosed with gestational diabetes, with twice the incidence rate of women born in Australia,' she said.
Women born in Southern Asia are at particularly high risk with an incidence rate 3.4 times the rate of Australian-born women.
Aboriginal and Torres Strait Islander women were diagnosed with gestational diabetes at a rate 1.5 times as high as other Australian women and had a higher risk across all age groups.