Anti-glutamic Acid Decarboxylase Antibody-Positive Gestational Diabetes Mellitus with Autoimmune Type 1 Diabetes Mellitus in the Early Postpartum Period: A Case Report and Literature Review

Gestational diabetes mellitus (GDM) is a state of pre-diabetic impaired glucose tolerance initially occurring during pregnancy. Although abnormalities in glucose metabolism normally resolve rapidly after delivery, women with GDM have a higher lifetime risk of developing diabetes mellitus than those without GDM; thus, postpartum healthcare is essential. Of all GDM patients, 5%-10% test positive for diabetes-related autoantibodies, which increase the risk of developing type 1 diabetes mellitus (T1DM). Autoantibody measurement in GDM screening remains debatable; however, it may be useful for the postnatal follow-up of GDM patients at high risk of developing T1DM. We treated a 29-year-old woman who was GDM positive for anti-glutamic acid decarboxylase antibody (GADA) requiring high-dose insulin therapy during pregnancy. As the patient tested positive for GADA, she received judicious postpartum management, allowing for early diagnosis of T1DM and resumption of treatment. Her insulin secretory capacity was preserved at 1 year after parturition, suggesting either slowly progressive insulin-dependent T1DM or latent autoimmune diabetes in adults. This was a rare case of slowly progressive insulin-dependent T1DM or latent autoimmune diabetes in adults in the early postpartum period, but the fact that GADA was positive during pregnancy enabled early treatment without overlooking it. Measuring diabetes-related autoantibodies in patients considered to be at a high risk for T1DM, such as those who are of slim build, young, or suffering from autoimmune thyroid disorders, may be important for appropriate individualized follow-up.