Screening for gestational diabetes mellitus in southern Asian women

To compare fasting plasma glucose (FPG) against 2-h postprandial plasma glucose (PPPG), following a carbohydrate meal, for screening of gestational diabetes mellitus (GDM) in southern Asian women with one or more risk factors.

A comparative study was conducted at a university obstetric unit in Sri Lanka. Two hundred and seventy one women undergoing oral glucose tolerance test (OGTT) according to the WHO criteria of 1999 had a 2-h PPPG performed within the following week. Sensitivity, specificity, predictive values and correlation coefficients for predicting a diagnosis of GDM and areas under receiver-operator curves (ROC) were calculated for FPG and PPPG. The ability to predict GDM and to reduce the need for OGTT were the main outcome measures.

The mean period of gestation was 26.43 weeks (SD = 5.4) Seventy-five (27.7%) women were diagnosed with GDM. The optimal threshold for FPG was 4.4 mmol/L and for PPPG 4.7 mmol/L. At these, sensitivity was 92.0% and 90.7%, specificity 48.7% and 25.4% and the areas under the ROC 0.82 and 0.73 for FPG and PPPG, respectively. Nine (12%) women could be diagnosed as having GDM on the basis of the FPG being above the threshold.

FPG is superior to 2-h PPPG for screening high-risk women for GDM. Nine women were diagnosed as having GDM on the basis of having an FPG above 7 mmol/L. FPG could reduce the number of OGTT needed by 40.9%, compared to 20.6% by PPPG. FPG is a less cumbersome and cost-effective screening test.