Objectives: The purpose of this study was to determine the incidence of diabetes in women with previous dietary-treated gestational diabetes mellitus and to identify predictive factors for development of diabetes.
Study design: Two to 11 years post partum, glucose tolerance was investigated in 241 women with previous dietary-treated gestational diabetes mellitus and 57 women without previous gestational diabetes mellitus (control group).
Results: Diabetes developed in 42 (17.4%) women with previous gestational diabetes mellitus (3.7% insulin-dependent diabetes mellitus and 13.7% non-insulin-dependent diabetes mellitus). Diabetes did not develop in any of the controls. Predictive factors for diabetes development were fasting glucose level at diagnosis (high glucose, high risk), preterm delivery, and an oral glucose tolerance test result that showed diabetes 2 months post partum. In a subgroup of previous patients with gestational diabetes mellitus in whom plasma insulin was measured during an oral glucose tolerance test in late pregnancy a low insulin response at diagnosis was found to be an independent predictive factor for diabetes development.
Conclusions: Women with previous dietary-treated gestational diabetes mellitus have a considerably increased risk of later having diabetes. Follow-up investigations are therefore important, especially in those women with previous gestational diabetes mellitus in whom the identified predictive factors are present.