Postpartum oral glucose tolerance tests in mothers of macrosomic infants: inadequacy of current antenatal test criteria in detecting prediabetic state

Objective: To assess the presence of subtle carbohydrate metabolism abnormalities in otherwise healthy mothers who have given macrosomic birth by utilizing postpartum oral glucose tolerance test (PPOGTT). Study Design: Prospective controlled study enrolled gestational diabetic women (GDM, n=10), mothers with macrosomic infants (MwMIs, n=62) and controls (n=50). Results: Receiver operating characteristic (ROC) curve analysis revealed that incremental 1-h+2-h PPOGTT value >111 mg/dl had a sensitivity of 80% and specificity of 78% in predicting antecedent diabetes. PPOGTT results were positive in 53.2% of MwMIs and 28% of controls (P<0.01). Maternal low-density lipoprotein and triglyceride levels, 50 gram glucose challenge test (50 g GCT) values and neonatal weight were the significant predictors of PPOGTT results. ROC analyses suggested that threshold of 50 g GCT should be lowered in order to better predict subjects with both macrosomia and positive PPOGTT. Conclusion: PPOGTT may identify a subset of women with macrosomic infants who have metabolic alterations of a prediabetic state. The discrepancies between antenatal and postpartum tests may reflect the need for redefinition of currently utilized criteria in screening and diagnosis of GDM. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.