Objective: To assess the performance of continuous glucose monitoring (CGM) metrics in predicting development of gestational diabetes mellitus (GDM) and adverse pregnancy outcomes. Methods: In a prospective observational study, CGM data were collected from 760 pregnant participants. Predictive CGM-based models were built using logistic and elastic net regression. Predictive performance was assessed by the area under the receiver operating characteristic curve (AUROC). Results: The AUROCs of using 2nd trimester % time &amp;gt;140 mg/dL (TA140) and week 13-14 TA140 in predicting GDM were 0.81 and 0.74, respectively. The AUROCs for predicting large for gestational age births (LGA) and hypertensive disorders of pregnancy (HDP) using 2nd trimester TA140 were both 0.58. Adding multiple predictors to the models did not meaningfully improve AUROC. When matching the specificity of OGTT, a model using TA140 in weeks 13-14 achieved similar sensitivity to OGTT in predicting HDP (13% vs. 10%, respectively) and LGA (6% for both) (Figure). Conclusion: CGM metrics such as TA140 predicted GDM with high AUROCs as early as 13-14 weeks’ gestation. CGM metrics at 13-14 weeks were statistically similar to OGTT at 24-28 weeks in predicting APOs although sensitivity was low for both. CGM could potentially be used as an alternative to OGTT and/or an early screening tool for elevated hyperglycemia during gestation. Disclosure Z. Li: None. R. Beck: Consultant; Insulet Corporation. Research Support; Insulet Corporation. Consultant; Tandem Diabetes Care, Inc. Research Support; Tandem Diabetes Care, Inc. Consultant; Beta Bionics, Inc. Research Support; Beta Bionics, Inc., Dexcom, Inc., Bigfoot Biomedical, Inc. Consultant; Novo Nordisk. Research Support; Novo Nordisk, Eli Lilly and Company. Consultant; embecta, Vertex Pharmaceuticals Incorporated, Hagar, Ypsomed AG, Sanofi, Zucara Therapeutics, Sequel. C. Durnwald: Consultant; Dexcom, Inc. Research Support; Dexcom, Inc. A.L. Carlson: Research Support; Medtronic, Insulet Corporation, Tandem Diabetes Care, Inc., Eli Lilly and Company, Sanofi. Other Relationship; Novo Nordisk. Advisory Panel; MannKind Corporation. Research Support; Dexcom, Inc. E. Norton: None. R.M. Bergenstal: Other Relationship; Abbott. Research Support; Arkray Marketing. Consultant; Ascensia Diabetes Care, Bigfoot Biomedical, Inc., CeQur. Other Relationship; Dexcom, Inc., Eli Lilly and Company. Consultant; embecta, Hygieia. Research Support; Insulet Corporation. Consultant; MannKind Corporation. Other Relationship; Medtronic, Novo Nordisk. Consultant; Onduo LLC, Roche Diabetes Care. Other Relationship; Sanofi. Research Support; Tandem Diabetes Care, Inc. Other Relationship; UnitedHealth Group. Consultant; Vertex Pharmaceuticals Incorporated, Zealand Pharma A/S. M.L. Johnson: Research Support; Abbott, Lilly Diabetes, National Institute of Diabetes and Digestive and Kidney Diseases, Novo Nordisk, Medtronic, Dexcom, Inc., Leona M. and Harry B. Helmsley Charitable Trust. Consultant; Jaeb Center for Health Research. Research Support; Patient-Centered Outcomes Research Institute, Jaeb Center for Health Research. S.M. Dunnigan: Research Support; Jaeb Center for Health Research, Patient-Centered Outcomes Research Institute, National Institute of Diabetes and Digestive and Kidney Diseases. M. Banfield: None. K.J. Krumwiede: None. J. Sibayan: None. P. Calhoun: None. Funding Study funding was provided by The Leona M. and Harry B. Helmsley and UnitedHealth Group. Dexcom provided the devices used in the study.

63-OR: Continuous Glucose Monitoring Prediction of Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes