1065-P: The Use of OGTT and Phenotypic Characteristics to Identify GDM Subtypes in Mexican Women, an Approach towards Precision Medicine

GDM is a heterogeneous disease. Three subtypes of GDM have been identified, insulin sensitivity defect, insulin secretion defect, and both. Insulin sensitivity defect is associated with higher risk for fetal overgrowth and GDM associated adverse outcomes. Based on the 2hr-OGTT-75g values, the phenotype of GDM-sensitivity is associated with elevated fasting glucose and GDM-secretion by elevated one and/or two hours post-load glucose values. We evaluated the 2hr-OGTT-75g values of 1713 in Mexican pregnant women without previous diagnosis of T2D from the cohort study Cuido mi Embarazo between April 20 and December 2021. We identified 251 cases of GDM (14.6%) . Based on the distribution of 2hr-OGTT-75g values related to known GDM subtypes, 132 (52.6%) had elevated fasting glucose but normal post-load glucose values (GDM-sensitivity) , 90 (35.8%) had elevated post-load glucose but normal fasting glucose values (GDM-secretion) , and 29 (11.6%) patients with elevated fasting and post-load glucose values (GDM-mixed) . Women in the GDM-sensitivity group were younger (27.3 ± 6.5 yr) , nulliparous (56.1%) and more often had a family history of T2D (50.0%) compared to the women in the GDM-secretion and GDM-mixed groups. However, there was no statistical difference between the principal groups regarding pregestational BMI (GDM-sensitivity: 27.7 ± 5.5; GDM-secretion: 27.4 ± 4.4; GDM-mixed: 28.4 ± 6.2 kg/m2, p=0.90) ; although this last group showed the higher prevalence of obesity (29.4% - 23.3% - 38.0% respectively for each group) . To our knowledge, this is the first analysis of GDM subtypes in Mexican pregnant women. The high proportion of GDM diagnoses with normal fasting glucose supports the importance of unavoidably offering a complete OGTT. This strategic approach by classifying GDM subtypes according to OGTT values takes clinical importance in the offering of personalized and timely management care to minimize perinatal and newborn adverse outcomes.