Pragmatic trials can address diagnostic controversies: recent lessons from gestational diabetes.

Objective: The aim of the paper is to discuss how a pragmatic definition could change our conception of diagnosis, using gestational diabetes mellitus (GDM) as an example.

Study Design: We review the diagnostic controversy that followed an observational study showing a linear relationship between maternal glycaemia and adverse pregnancy outcomes and the resolution proposed 15 years later by a recent pragmatic trial comparing two screening approaches (one- vs two-step) with different diagnostic thresholds.

Results: The pragmatic trial involved approximately 24,000 women.

Establishing consensus in the diagnosis of gestational diabetes following HAPO: where do we stand?

New proposals for the diagnosis of gestational diabetes (GDM), promulgated by the International Association of Diabetes and Pregnancy Study Groups (IADPSG), will substantially increase the number of women diagnosed with GDM. This will have an enormous impact on healthcare resources, diverting attention away from genuinely high risk diabetic pregnancies. Randomized trials in 'mild' GDM indicate that the main effects of treatment are a 2 %-3 % reduction in birth weight, fewer 'big babies', and less shoulder dystocia.