<qa>  What is the reason for the lack of consensus on the best method to identify cases of GDMRationale: There is no consensus on the best method to identify cases of GDM, numerous screening and diagnostic procedures are employed worldwide. Recently the Canadian Guidelines recommended a new set of values based on normative data, yet these data have not been validated against a large population and compared with diagnostic rates and outcomes head to head against the long accepted values of OSullivan and Mahan. In addition, the question of cost in a Canadian healthcare setting has never been addressed yet it is a significant societal concern. The results of this study would help clarify these issues using evidence-based methodology. 