The role of first-trimester HbA1c in the early detection of gestational diabetes

Abstract

Background We aimed to assess the utility of HbA1c in the early detection of gestational diabetes (GDM) in the first trimester. Methods This prospective study was performed on 700 pregnant women in the perinatology clinic at a tertiary university hospital from March 2018 to March 2020. For all pregnant women, HbA1c and fasting blood glucose (FBG) levels were examined during the first trimester. Then, a GDM screening test was done within 24–28 weeks of pregnancy using a 100 g oral glucose tolerance test (OGTT) as the gold standard test. The GDM diagnosis was made according to the American Diabetes Association (ADA) criteria. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of HbA1c and FBG were calculated using the receiver operating characteristic (ROC) curve. Results Of 700 participants, one hundred and fifteen (16.4%) women had GDM. The GDM patients were significantly older and had a higher pre-gestational body mass index and pregnancy weight gain compared to the non-GDM participants. The sensitivity and specificity for ruling out GDM at an HbA1c cut-off value of 4.85% was 92.2 and 32.8%, respectively, with a 95.5% NPV and a 21.2% PPV. Furthermore, sensitivity and specificity for diagnosing GDM at an HbA1c cut-off value of 5.45% was 54.8 and 96.8%, respectively, with a 91.5% NPV and a 76.8% PPV. Using HbA1c could decline OGTT in 40.4% of the pregnant women (28.7% with HbA1c < 4.85 and 11.7% with HbA1c ≥ 5.45%). Conclusion It seems that the first-trimester HbA1c cannot replace OGTT for the diagnosis of GDM because of its insufficient sensitivity and specificity. However, women with higher first-trimester HbA1c had a high risk for GDM incidence.

Evaluation of First Trimester Fasting Blood Glucose, HOMA-IR and HbA1c in Prediction of Gestational Diabetes Mellitus in Non-Obese Pregnant Women: A Retrospective Study

“…In addition, physiological hydration, anemia, slower intestinal transit, increased erythrocyte life cycle and nutritional changes are the factors that can significantly affect the HbA1c value during pregnancy (27). Therefore, there is no guideline for the use of HbA1c in the diagnosis of GDM (19).…”

Evolution of Gestational Diabetes Mellitus across Continents in 21st Century

“…The first-trimester glycated hemoglobin (HbA1c) assessment is pointed out to be an additional prognostic marker and should not be analyzed separately. Its insufficient sensitivity and specificity may not detect the whole population of patients [ 10 , 11 ].…”

Is HbA1c or two-step glucose tolerance testing preferable for early diabetes screening in pregnancy?

“…4 A 2022 prospective cohort study of 700 women examined the utility of HbA1c in first trimester detection of GDM. 5 In pregnant women with GDM, the average HbA1c level was 5.45% compared with 4.96% in the women without GDM. 5 The sensitivity and specificity varied based on the HbA1c cut-off and was 92% and 33% for a cut-off of 4.85 and was 55% and 97% for a cut-off of 5.45.…”

“…5 The sensitivity and specificity varied based on the HbA1c cut-off and was 92% and 33% for a cut-off of 4.85 and was 55% and 97% for a cut-off of 5.45. 5…”