Impaired early phase insulin secretion associated with gestational diabetes mellitus in underweight women.

Background: No reports have focused on the clinical and metabolic characteristics of gestational diabetes (GDM) in underweight women. The aim of this study is to investigate the clinical and metabolic features of underweight GDM (pregravid BMI, <18.5 kg/m2: U-GDM).Materials and methods: Women diagnosed with GDM were categorized based on their pre-pregnancy BMI as either underweight (n = 49) or normal weight (pregravid BMI, 18.5-25.0 kg/m2: n = 271: N-GDM). During the study period, GDM was diagnosed using the International Association of Diabetes in Pregnancy Study Group criteria. Women with multi-fetal pregnancies, fetal congenital anomalies, overt diabetes in pregnancy, and pre-gestational diabetes mellitus were excluded.Results: There were no notable differences in maternal age at delivery and the rate of nulliparous between the U-GDM and N-GDM groups. Regarding antepartum oral glucose tolerance test profiles, women with U-GDM exhibited significantly lower fasting plasma glucose (FPG) levels than those with N-GDM (p < .01). The Insulinogenic Index of women with U-GDM was significantly lower than that of women with N-GDM (p < .05).Conclusion: Impaired early phase insulin secretion was associated with GDM onset in underweight women.