A Study to Find the Utility of HbA1c in the Diagnosis of Gestational Diabetes Mellitus

Introduction: Gestational Diabetes Mellitus (GDM) is a significant pregnancy complication requiring timely diagnosis to prevent adverse outcomes. While the oral glucose tolerance test (OGTT) is standard, its limitations have prompted interest in alternative markers like HbA1c. This study aims to evaluate HbA1c’s diagnostic utility in GDM, particularly when combined with glucose testing. Methods: This cross-sectional study, conducted over 12 months, involved pregnant women without diabetes. GDM diagnosis was based on a 75-gram OGTT, while HbA1c levels were measured using HPLC. Sensitivity, specificity, and ROC analysis determined HbA1c’s diagnostic accuracy. The study also evaluated HbA1c’s association with pregnancy outcomes like birth weight and complications. Results: In this study of 300 pregnant women, 68 (22.7%) were diagnosed with GDM. The mean HbA1c level in GDM cases was 5.8% versus 5.2% in non-GDM (p<0.05). HbA1c showed 72% sensitivity, 85% specificity (AUC 0.78). Combining HbA1c with fasting glucose improved sensitivity to 82%, enhancing GDM detection. Conclusion: HbA1c demonstrates moderate diagnostic accuracy for GDM, with fair sensitivity and specificity. When combined with fasting glucose, its diagnostic performance significantly improves, enhancing GDM detection. Elevated HbA1c levels are also linked to adverse pregnancy outcomes, highlighting the importance of using HbA1c as an adjunct diagnostic tool for GDM.