Gestational diabetes increases a woman's risk of type 2 diabetes by 700 per cent, raising their chances of a heart attack, warns a public health expert.

A rise in a highly preventable pregnancy complication has raised concerns among public health experts that thousands of young Australian women are at future risk of a heart attack or stroke.

Gestational diabetes affects an estimated 7-8 per cent of pregnant women in Australia.

Globally, an estimated 15 per cent of pregnancies are affected by the disease.

Chief Scientist at The George Institute for Global Health, Professor Anushka Patel says in some parts of the urban world, particularly in East Asia and South Asia, it's getting up to 20 per cent or higher.

The Professor in Medicine says many of those young women of reproductive years aren't aware of the significant long-term risks of having had gestational diabetes.

"While many of them return to a normal glucose status immediately post delivery, a very large proportion of them will develop type 2 diabetes in their late 30s early 40s, essentially increasing their risk of heart attack or stroke by three times, so this is a major risk factor for heart disease, Professor Patel told AAP.

In fact, if a woman develops gestational diabetes they have a 700 per cent, or seven-fold, increased chance of developing type 2 diabetes.

"And then if you develop diabetes you have a three times increased risk of having a heart attack or stroke," Professor Patel said.

Speaking at a Heart Foundation forum in Sydney this week, Professor Patel warned of an impending global health problem, saying prevention is the key to reducing the burden of heart disease - the number one killer of women in Australia.

"It's not only an important problem it's a potentially preventable problem," she said.

Prof Patel believes the problem is that there is currently no mechanism to ensure affected women are regarded high risk for the rest of their lives.

"We are really missing out on an opportunity to intervene early to prevent diabetes and then complications of diabetes in these people," she said.

"First of all there's opportunities to try to prevent women from developing diabetes and then if you identify a woman who's got diabetes there's lots of things you can do to reduce the risk of developing a heart attack or stroke," Prof Patel said.

Maintaining a healthy weight and exercise will help to prevent gestational diabetes, says Prof Patel.