Objectives: This study aims to determine the role of HbA1c level during first trimester in predicting gestational diabetes mellitus in Filipino non-diabetic women. Hence, to identify those will be at increased risk of its adverse maternal and perinatal outcomes, and who will benefit from early intervention. This will aid in preventing maternal and perinatal morbidity and mortality and reducing health care cost by avoiding strategies which can result in false positive cases. Methodology: A cross-sectional study conducted in a tertiary hospital in the Philippines. Seventy-one Filipino pregnant women were included in the final analysis. HbA1c levels were taken during the first trimester and routine screening of gestational diabetes mellitus (GDM) utilizing 75 grams OGTT during 24th-28th weeks age of gestation. Binary logistic regression modeling was performed to determine if HbA1c was a predictor of gestational diabetes mellitus. The calculated median for Hba1c was then utilized as a threshold value to predict GDM. Odds ratio, relative risk and corresponding 95% confidence intervals from binary logistic regression were computed to determine the association of variables. Results: In this study the prevalence rate of GDM is 38%. It showed that first-trimester HbA1c level is not a predictor of GDM and adverse maternal and perinatal outcomes. However, in utilizing an HbA1c threshold of ≥ 5.2%, there is a two-fold increase risk of developing hypertensive disorders, requiring insulin during pregnancy, and macrosomic newborns and a four-fold increase risk of having large for gestational age newborns. It has a positive predictive value (PPV) of only 16%. However, it has a high negative predictive value (NPV) of 88% therefore it can be used to rule out risk of GDM as early as in the first trimester. Conclusion The association of HbA1c level and the occurrence of GDM was not observed in this study. However, by using an HbA1c threshold of ≥ 5.2%, as opposed to the standard reference range for diagnosing type 2 diabetes mellitus and gestational diabetes mellitus in Caucasians, the relative risk of developing GDM in 24th-28th weeks AOG is 1.26 (0.6865, 2.3242).
Diabetes, Gestational ; Pregnancy ; Insulin