Prediction of abnormal postpartum glucose tolerance testing in mild gestational diabetes mellitus.

Objective: To describe the liikelihood of women with gestational diabetes mellitus (GDM)--who are at increased risk for developing overt diabetes--undergoing postpartum testing, and the patient characteristics associated with abnormal postpartum glucose tolerance testing (GTT) in mild GDM.

Study Design: This was a retrospective chart review that included mild GDM patients, defined as those with fasting plasma glucose levels < 95 mg/dL on a 3-hour 100-g oral glucose tolerance test (OGTT). Patients who underwent postpartum testing were assessed and predictive factors for abnormal results evaluated.

Results: Mild GDM was diagnosed in 414 (39.6%) women, 201 (48.6%) of whom completed a postpartum 2-hour 75-g OGTT. Abnormal testing was seen in 69 (34.3%), with diabetes in 6 (3%); those with abnormal testing had been diagnosed with GDM at an earlier gestational age, had higher 1-hour 50-g OGTT values, and were also more likely to require pharmacologic therapy. Combining several variables produced a predictive model with positive and negative predictive values of 50% and 84%, respectively.

Conclusion: Antenatal factors (alone or in combination) do not allow for prediction of abnormal postpartum OGTT results in mild GDM patients. Patients with mild GDM are at a slightly decreased postpartum risk of developing diabetes and prediabetes as compared to other patients with GDM.