1908-P: Continuous Glucose Monitor Metrics as Predictors for Obstetric Outcomes among Patients with Diabetes in Pregnancy

Introduction and Objective: Continuous glucose monitor (CGM) use has increased among pregnancies complicated by gestational (GDM) and type 2 diabetes (T2DM). There is limited data on CGM metrics for optimal glycemic control in pregnancy. Thus, this study aimed to evaluate the association between CGM metrics and large for gestational age (LGA) and adverse pregnancy outcomes (APO) among patients with GDM and T2DM. Methods: This was a retrospective cohort study of all pregnant patients with GDM or T2DM utilizing a CGM, managed in a diabetes in pregnancy program in 2025. CGM metrics, included time in range (TIR), time above range (TAR), time below range (TBR), average glucose, and glucose variability, over the last ninety days of pregnancy. LGA was defined as birthweight ≥90th percentile. APO included hypertensive disorder of pregnancy, shoulder dystocia, neonatal hypoglycemia, neonatal respiratory distress, NICU admission, fetal death, or neonatal death. Receiver operating curves were constructed and area under the curve (AUC) with 95% confidence intervals (CI) were reported to estimate the predictability of each metric for LGA or APO. A Youden index was calculated if AUC was ≥0.65 to estimate an optimal threshold. Results: Of the 53 included patients, seven (13.2%) had LGA and 21 (39.6%) had an APO. TIR (AUC 0.78, 95% CI 0.59-0.98) and TAR (AUC 0.78, 95% CI 0.55-0.99) were moderate predictors LGA. Average glucose (AUC 0.67, 95% CI 0.40-0.94), glucose variability (AUC 0.68, 95% CI 0.45-0.91) and TBR (AUC 0.39, 95% CI 0.18-0.60) were fair predictors of LGA; Optimal thresholds for TIR and average glucose were 85% and 138 mg/dL, respectively. TIR (AUC 0.68, 95% CI 0.52-0.84), TAR (AUC 0.68, 95% CI 0.52-0.84), and average glucose (AUC 0.67, 95% CI 0.0.51-0.82) were fair predictors of APO. Optimal thresholds for TIR, TAR, and average glucose were 75%, 19%, and 121 mg/dL, respectively. Conclusion: In our cohort of patients with GDM and T2DM, we found that TIR 85% was a moderate predictor for LGA and an average glucose 120 mg/dL was a fair predictor of APO. Disclosure E.S. Markovic: None. I. Ojei-Ossai: None. C. Rosenzweig: None. L. Pessoa: None. I. Futterman: None. R. McLaren: None.