Evaluation of B-cell secretion and peripheral insulin resistance during pregnancy and after delivery in gestational diabetes mellitus with obesity.

Nine pregnant women with gestational diabetes mellitus (GDM) were studied. Six normal pregnant women and six normal nonpregnant women were evaluated as control groups. All the women underwent oral glucose tolerance test and glucose clamp during the third trimester of pregnancy and two months after delivery. During OGTT, glucose, C-peptide and insulin plasma levels were determined. C-peptide and insulin values in the late phase of OGTT were higher during pregnancy than after delivery in both groups. In gestational diabetic women, the M-value in the second steady-state during glucose clamp was lower than in controls, both during pregnancy and after delivery. Nevertheless, in both groups the M-value during pregnancy was lower than after delivery. Moreover, in gestational diabetic women there was an inverse correlation between M-value in the second steady-state and ponderal excess index after delivery. In conclusion, the impaired peripheral glucose utilization and the pancreatic pattern of gestational diabetic women compared to normal suggested altered B-cell secretion response, increased peripheral resistance and overweight to be the main changes in GDM.