Prediction of gestational diabetes mellitus at 24 to 28 weeks of gestation by using first-trimester insulin sensitivity indices in Asian Indian subjects.

The aim of the present study was to predict the development of gestational diabetes mellitus (GDM) after 24 weeks of gestation by using first-trimester insulin indices. A total of 298 nondiabetic pregnant women underwent 3-hour oral glucose tolerance test (OGTT) in the first trimester of pregnancy. The normoglycemic women underwent second OGTT between 24 and 28 weeks. Insulin sensitivity and resistance indices were calculated by using the Matsuda index (composite insulin sensitivity from OGTT), quantitative insulin sensitivity check index, and homeostasis model assessment for insulin resistance and sensitivity by using the results of the first-trimester OGTT. These indices were compared between subjects who were diagnosed as having GDM and subjects with normal glucose tolerance in the second OGTT. The overall prevalence of GDM was 15.49% (24 in the first trimester and 16 between 24 and 28 weeks). First-trimester fasting plasma insulin greater than 7.45 μU/mL was able to predict GDM with sensitivity and specificity of 80% and 57.4%, respectively. The negative predictive value for this parameter was 0.97. Values of first-trimester composite insulin sensitivity from OGTT less than 5.5 had sensitivity and specificity of 71.4% and 62.5% for the prediction of GDM. First-trimester hyperinsulinemia preceded the onset of hyperglycemia between 24 and 28 weeks of gestation and would predict the development of GDM with limited sensitivity and specificity.