Gestational Diabetes Mellitus Subtypes Classified by Oral Glucose Tolerance Test and Maternal and Perinatal Outcomes: Results of a Mexican Multicenter Prospective Cohort Study “Cuido Mi Embarazo”

Purpose: This study explores the impact of gestational diabetes mellitus (GDM) subtypes classified by oral glucose tolerance test (OGTT) values on maternal and perinatal outcomes.Patients and Methods: This multicenter prospective cohort study (May 2019-December 2022) included participants from the Mexican multicenter cohort study Cuido mi Embarazo (CME).Women were classified into four groups per 75-g 2-h OGTT: 1) normal glucose tolerance (normal OGTT), 2) GDM-Sensitivity (isolated abnormal fasting or abnormal fasting in combination with 1-h or 2-h abnormal results), 3) GDM-Secretion (isolated abnormal values at 1-h or 2-h or their combination), and 4) GDM-Mixed (three abnormal values).Cesarean delivery, neonates large for gestational age (LGA), and pre-term birth rates were among the outcomes compared.Between-group comparisons were analyzed using either the t-test, chi-square test, or Fisher's exact test.Results: Of 2,056 Mexican pregnant women in the CME cohort, 294 (14.3%) had GDM; 53.7%, 34.4%, and 11.9% were classified as GDM-Sensitivity, GDM-Secretion, and GDM-Mixed subtypes, respectively.Women with GDM were older (p = 0.0001) and more often multiparous (p = 0.119) vs without GDM.Cesarean delivery (63.3%; p = 0.02) and neonate LGA (10.7%; p = 0.078) were higher in the GDM-Mixed group than the overall GDM group (55.6% and 8.4%, respectively).Pre-term birth was more common in the GDM-Sensitivity group than in the overall GDM group (10.2% vs 8.5%, respectively; p=0.022).At 6 months postpartum, prediabetes was more frequent in the GDM-Sensitivity group than in the overall GDM group (31.6% vs 25.5%).Type 2 diabetes was more common in the GDM-Mixed group than in the overall GDM group (10.0%vs 3.3%).Conclusion: GDM subtypes effectively stratified maternal and perinatal risks.GDM-Mixed subtype increased the risk of cesarean delivery, LGA, and type 2 diabetes postpartum.GDM subtypes may help personalize clinical interventions and optimize maternal and perinatal outcomes.