Women who develop gestational diabetes are at greater risk of developing Type 2 diabetes after their pregnancies are over, new Canadian research says.

According to a study published in the Canadian Medical Association Journal, 18.9 per cent of women who had gestational diabetes developed Type 2 diabetes within nine years of pregnancy.

In contrast, of the women who did not have gestational diabetes, only two per cent developed Type 2 diabetes.

The study was conducted by a group of researchers from the University of Toronto, Mount Sinai Hospital and the Institute for Clinical and Evaluative Sciences.

"The main strength of our study lies in the fact that it was a large population-based study involving more than 21,000 women with gestational diabetes, with up to nine years of follow-up," the researchers wrote.

"Unlike other studies, it covered a large, well-defined geographic region with a population of 13 million, which allowed us to make a more robust assessment of the risk of Type 2 diabetes after gestational diabetes than has been possible in previous studies."

The researchers noted that gestational diabetes is on the rise in Ontario, the province from which they drew their subjects. This could be because women are having babies when they are older, which puts them at greater risk for the condition.

The researchers admitted that one drawback of the study was the fact that they were unable to assess their subjects' ethnicity and obesity and blood-sugar levels while they were pregnant, all of which are risk factors for diabetes.

However, they recommend that women who develop gestational diabetes receive regular post-pregnancy screening tests for Type 2 diabetes. As well, they encourage doctors to educate their patients about diabetes preventative measures, such as improved diet and exercise.