Normal pregnancy is a diabetogenic state with increased insulin resistance. Gestational diabetes mellitus (GDM) is a common medical complication during pregnancy. This hospital-based prospective observational study of 112 patients evaluated HbA1c levels before 14 weeks of gestation and pregnancy outcomes. Screening for GDM was performed at 24–26 weeks using OGTT. Results indicated that HbA1c ≥ 5.7% correlated with maternal, fetal, and neonatal complications, with sensitivity of 89% and specificity of 80%. Early pregnancy HbA1c can predict GDM and adverse outcomes, serving as an additional screening tool alongside OGTT. © 2024 Elsevier B.V., All rights reserved.