Is HbA1c Predictive for Screening and Diagnosis of Gestational Diabetes Mellitus?

OBJECTIVE: Evaluation of HbA1c value in diagnosis of gestational diabetes mellitus. STUDY DESIGN: This retrospective cohort study included 131 women with gestational diabetes mellitus (GDM) that were screened and diagnosed between the 24-28 weeks of gestation by two-step testing regimen in Etlik Zübeyde Hanım Women’s Health Research and Educational Hospital. Venous blood samples of these women were collected for HbA1c. One sample test was performed to test the difference between our HbA1c results and the value in the literature. RESULTS: The mean HbA1c result in our study was 5.6% (min:4.4%, max:8.0%), standard deviation was 0.5. We compared our results with the cut off value of 5.5 % that was notified for second trimester for non-diabetic pregnancies by different authors. Our HbA1c value that was 5.6% was significantly higher than the cut off values (5.5%) that was reported (p=0.008). CONCLUSION: There is an ambiguity for the threshold values of HbA1c in GDM. Further studies are needed to evaluate true cut-off values for using HbA1c for screening and diagnosing GDM.