First trimester glycosylated hemoglobin for gestational diabetes mellitus screening.

Objective: Our aim in this study is to evaluate the efficacy of HbA1c in screening for GDM during the first trimester of pregnancy.

Materials And Methods: In this retrospective cohort study, we evaluated the first trimester HbA1c (ft-HbA1c) levels of 195 pregnant women who attended our university hospital's obstetrics clinic. Blood samples were drawn from patients during 11-14 weeks of gestation. After that, all patients were screened using standardized one-step 75gr OGTT between 24 and 28 weeks of pregnancy.

Results: In this study, 195 pregnant women were included. Thirty-two (16.4%) of the women included in this study were diagnosed with GDM. The mean ft-HbA1c level was 5.52% in those who developed GDM and 5.21% in those who did not develop GDM (p = 0.000). Only seven (3.6%) of the women included in this study had an ft-HbA1c level above the prediabetes limit of 5.7%. All these women with prediabetes developed GDM. The cut-off value for ft-HbA1c to distinguish GDM was 5,33%. For this cut-off value, the sensitivity was 71.9%, and the specificity was 82.8%.

Conclusion: The findings suggest that ft-HbA1c level is a promising biomarker for GDM screening. Especially, patients with ft-HbA1c level ≥5.33% are at increased risk for developing GDM.