Characteristics of insulin secretion patterns in Japanese women with overt diabetes and gestational diabetes defined according to the International Association of Diabetes and Pregnancy Study Groups criteria

Aim:  To characterize patterns of insulin secretion in women with overt diabetes and gestational diabetes (GDM) defined by the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. Material and Methods:  A total of 228 Japanese women were examined retrospectively. All 228 women had a positive 50-g glucose challenge test (GCT) result at 25.2 ± 1.2 weeks of gestation and underwent a 75-g glucose tolerance test (GTT) at 27.4 ± 1.8 weeks of gestation. The immunoreactive insulin levels were determined during the GTT in four groups of pregnant women: five with overt diabetes, 20 with GDM according to both the previous Japan Society of Gynecology and Obstetrics (JSOG) and current IADPSG criteria (traditional GDM group), 43 with GDM according to only the IADPSG criteria (new GDM group), and 160 with non- GDM, but with a positive GCT result. Results:  Attenuated and slow rise in plasma insulin in concert with prolonged hyperglycemia were characteristic in women with overt diabetes, compared with women with GDM in whom excessive insulin secretion in the presence of hyperglycemia was characteristic. The new GDM group did not differ significantly from the traditional GDM group with respect to scores of such indices as the insulinogenic index, the homeostasis model assessment for insulin resistance, and the quantitative insulin sensitivity check index. Conclusion:  Women with overt diabetes have both an impaired capacity for insulin secretion and elevated insulin resistance, while women with GDM exhibit a maintained insulin secretory capacity with an elevated insulin resistance.