Aims: The prevalence of gestational diabetes mellitus (GDM) has recently increased all over the world. It is hard to predict insulin need during pregnancy even if the insulin secretory capacity is evaluated when studying 75-g OGTT to screen for GDM. The role of glucagon abnormality has remarked in pathogenesis of type 2 diabetes, however, still unknown in GDM. This study was aimed to evaluate glucagon responses in GDM and to investigate whether measurement of glucagon is useful to anticipate insulin need during pregnancy.
Methods: Forty-nine women diagnosed with GDM based on IADPSG criteria were enrolled into the study and re-studied OGTT during mid-gestation to evaluate glucagon responses. Plasma glucagon levels were measured before and 30, 60, 120 min after glucose load using a sandwich ELISA kit. Insulin treatment was initiated when either a fasting glucose >95 mg/dL or postprandial 2-h glucose >120 mg/dL continues for more than a week after starting diet therapy.
Results: Of 49 patients, fifteen were required insulin (defined as GDM/Insulin) and 34 could be treated with diet therapy alone until delivery (defined as GDM/Diet). GDM/Insulin was started insulin treatment at 29.6±3.6 weeks of gestation and the maximum insulin dose was 39.0±24.8 units/day. There were no significant differences in maternal age, pre-gravid BMI and insulin secretory responses during OGTT between the groups. Although fasting glucagon levels were not different between the groups, paradoxical increases in early-phase glucagon secretion after glucose load were observed in GDM/Insulin but not in GDM/Diet. The changes in glucagon levels (pg/mL) from 0 min to 30 min were significantly different between the groups (1.3±8.1 in GDM/Insulin vs. -4.2±4.0 in GDM/Diet, p<0.01), and the ROC analysis of the value to predict insulin need was -2.01 pg/mL.
Conclusions: Impaired early-phase glucagon suppression might be useful to predict for insulin need during pregnancy in GDM.
I. Horie: None. A. Haraguchi: None. N. Abiru: None. A. Kawakami: None.