Gestational Diabetes Mellitus (GDM) is a major health concern for Mexican women, with a high prevalence that can lead to long-term consequences if left untreated. The mother's risk of developing diabetes in later life increases by up to 10 times if GDM is not addressed properly and some women may experience Prediabetes or new-onset Diabetes after childbirth. Metabolic reevaluation testing following pregnancy becomes essential for those who have had GDM. Nevertheless, this practice is uncommon. In this study, 1,611 pregnant women were followed during pregnancy, puerperium and at the time of metabolic reevaluation tests following pregnancy for women who have undergone GDM as part of the cohort study Cuido mi Embarazo in Mexico between April 2019 and November 2022. After the follow-up period, 161 (10%) cases of GDM were identified. At the time of the metabolic reevaluation after pregnancy, 136 (84.5%) women were classified as healthy, 21 (13.0%) as having Prediabetes, and 4 (2.5%) with new-onset Diabetes. Glucose values in the 2-h 75-g OGTT for GDM diagnosis were higher for those with impaired glycemia at the moment of metabolic reevaluation. In addition, women with altered glycemia at the time of reclassification tended to be older (32.0 ± 6.2), 52% a phenotypic sub-type of GDM associated with insulin resistance and 24.0% sub-type of GDM associated with insulin resistance and insulin secretion. Moreover, 60.0% had a family history of diabetes, 11.8% had previous pregnancies with newborns who were macrosomic, and 40.0% were obese based on their pregestational BMI category. It is of the utmost importance for all women with GDM to undertake a metabolic reevaluation test that can detect Prediabetes or new-onset Diabetes after pregnancy, so as to initiate immediate treatment and protect women from potential long-term health issues if left unattended. In addition, it becomes imperative that all women with GDM have recurrent screening throughout life due to their high risk of developing Diabetes. Disclosure L.Martinez-juarez: None. H.Gallardo-rincón: None. A.Montoya: None. J.Ortega-montiel: None. D.Álvarez-hernández: None. E.Reyes-muñoz: Speaker's Bureau; Exelixis. R.Mujica-rosales: None. R.Tapia-conyer: None. Funding Eli Lilly and Company