Gestational diabetes mellitus (GDM) is a condition of abnormal maternal glucose tolerance that occurs, or is detected, for the first time during pregnancy. The new diagnostic strategies recommend a 75 g, 2-h glucose tolerance test for all women not already known to be diabetic, in the early 3rd trimester of pregnancy. GDM is diagnosed when one or more values is equal to or exceeds the thresholds suggested (i.e. fasting ≥ 5.1 mmol/l, 1-h ≥ 10.0 mmol/l and 2-h ≥ 8.5 mmol/l). This criteria will determine a significant increase of the prevalence of GDM, primarily because only one abnormal value (OAV), not two, is sufficient to make the diagnosis. We also suppose that the new cases of gestational diabetes diagnosed with the new criteria will have an increased risk for subsequent abnormal glucose tolerance later in life, as it was largely confirmed in the past for the patients with two or more abnormal values.