Postpartum oral glucose tolerance tests in mothers of macarosomic 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.