Hemoglobin A1C in the first trimester of pregnancy as a predictor of gestational diabetes mellitus: A retrospective study in Saudi Arabia.

Abstract

This study evaluates the association between first-trimester hemoglobin A1c (HbA1c) levels and glucose tolerance test (GTT) results to assess the utility of HbA1c as a predictive biomarker for gestational diabetes mellitus (GDM). A retrospective, descriptive study was conducted on 634 pregnant women between January and December 2022 at Prince Sultan Military Medical City, Riyadh, Saudi Arabia. After excluding cases with HbA1c ≥6.5% (48 mmol/mol), 552 participants were included in the final analysis. Data on demographic characteristics, HbA1c levels, biochemical parameters, and GTT results were collected and analyzed. Out of 552 participants, 183 (33%) were diagnosed with GDM. Among those with elevated HbA1c levels (≥5.6), 59 (54%) had GDM. Additionally, 99 (17.9%) women had a single positive oral glucose tolerance test (OGTT), while 50 (9.1%) had two positives, and 34 (6.2%) had three positives. A significant difference in fasting glucose levels was observed between pregnant women with GDM and normal HbA1c (<5.6%) (4.78 ± 0.76) and those with elevated HbA1c (≥5.6%) (5.39 ± 1.47) (<i>P</i> = 0.001). Pregnant women with GDM exhibited significantly higher fasting glucose (4.98 ± 1.08 mmol/L) and HbA1c levels (5.54 ± 0.43%) compared to non-GDM counterparts (4.32 ± 0.76 mmol/L; 5.31 ± 0.33%, <i>P</i> = 0.001). Measurement of HbA1c during the first trimester may be a useful approach for identifying pregnant women at an increased risk of GDM. Incorporating HbA1c testing into standard prenatal care could enable earlier risk assessment and prompt interventions, helping to reduce unfavorable outcomes for both mother and fetus. Additional research is needed to confirm these results and determine the most appropriate HbA1c cutoff values for clinical practice.