Objective: In comparison a higher insulin-glucose-index is usually associated with an increased insulin resistance. In the present study changes in insulin-glucose-indices were examined in relation to a defined glucose tolerance in the last trimester of pregnancy.
Material and methods: 249 pregnant women were challenged with a 75 gm oral glucose tolerance test (oGTT). Serum samples for glucose (glucose-dehydrogenase-method) and insulin measurements (RIA) were drawn before and at 30, 60, 120, and 180 minutes after glucose load during oGTT. Patients were assigned to five groups with increasing glucose intolerance according to maximal glucose levels during the test.
Results: There were no significant differences in insulin-glucose-indices prior to glucose load. Pregnant women with gestational diabetes were shown to have significantly lower insulin-glucose-indices in the early and intermediate phase of the challenge test while the indices were higher in the final phase of the test.
Conclusions: Women with gestational diabetes demonstrated an initial delay in insulin secretion in combination with a higher insulin-glucose-index, corresponding to an increased insulin resistance, only in the end of the test. These characteristics may possibly be a cause of the observed disorder in glucose metabolism in these patients.