6938 An Unusual Case of New-onset autoimmune insulin dependent Diabetes Mellitus Complicating Gestational Diabetes Mellitus in A Pregnant Female Diagnosed Early Postpartum - The Enigma of Autoimmunity and Diabetes During Pregnancy
Authors: Abdelmasih Randa , Pan Wentong 
Published: October 2024

Abstract
Disclosure: R. Abdelmasih: None. W. Pan: None.
Introduction: Gestation diabetes is the most common metabolic disorder in pregnancy affecting 25% of pregnancies. T1DM accounts for 0.2-0.5% of all pregnancies in the United States yearly. New-onset autoimmune insulin-dependent diabetes mellitus during pregnancy is very uncommon and it might be overlooked. Diabetes-related autoantibodies have been studied in women with GDM with prevalence of 0-10%. There is controversial data regarding the clinical significance of checking diabetes antibodies in pregnancy. Case Presentation: A 22-year-old G1P1 female with history of Hashimoto hypothyroidism presented during early second trimester for evaluation of GDM with serum glucose of 300s mg/dl in a random blood sample with multiple subsequent high values, hemoglobin A1C of 9.4% (prepartum value was 5.3%). Patient was started on insulin during pregnancy. Pregnancy was complicated with cesarian section and macrosomia. 1 week postpartum, A1c was 5.4%, Insulin was discontinued, and patient was continued on Metformin. 2 months Postpartum, patient presented with persistent high blood glucose values of 300-400 mg/dl with no signs of DKA. Glipizide and Glargine 15 units daily were added though patient continued to have hyperglycemia. Laboratory workup were remarkable for high blood glucose of 342 mg/dl, low C peptide of 0.6 ng/dl, and positive glutamic acid decarboxylase antibodies (GAD Ab) 38.8 U/ml. oral antidiabetics were discontinued and prandial insulin was added. Discussion: GDM is a risk factor for DMII after pregnancy given high insulin resistance postpartum, Data regarding new-onset DMI and diabetes autoimmunity during pregnancy is lacking. About 0-10% of women with gestational diabetes develop DM autoantibodies. GAD Ab exhibits the highest sensitivity of 63% for type 1 diabetes prediction compared to Islet cell antibodies (48%), and tyrosine phosphatase-related islet antigen 2 (34%). Pathophysiology of autoimmune DM during pregnancy is not quite understood; It is thought that when autoimmune tendency is present, GDM causes β-cells to deteriorate due to excessive insulin production in setting of insulin resistance, and the burden of third-trimester gestation may cause the insulin deficiency to be expressed sooner than non-pregnant female. So far, Literature about the predictive value or specific clinical features of checking diabetes autoantibodies is discordant and inconclusive. It is suggested to screen for autoantibodies only when array of clinical hallmarks suggestive of an autoimmune DM form of GDM present as young age, low BMI, need for insulin therapy early in pregnancy, presence of ketones, concurrent other autoimmune conditions (e.g., thyroiditis). This case is to shed light on autoimmunity in pregnancy. More data is needed with longer follow-up to better identify women at risk, their characteristics, indications for autoantibodies testing, follow and prognosis.
Presentation: 6/2/2024