American Diabetes Association
06_Online_Supplemental_Material_GLAM_GDM_v_No_GDM_01-24-24.pdf (542.65 kB)

Continuous Glucose Monitoring (CGM) Profiles in Pregnancies with and without Gestational Diabetes Mellitus

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posted on 2024-05-03, 20:02 authored by Celeste Durnwald, Roy W. Beck, Zoey Li, Elizabeth Norton, Richard M. Bergenstal, Mary Johnson, Sean Dunnigan, Matthew Banfield, Katie Krumwiede, Judy Sibayan, Peter Calhoun, Anders L. Carlson

Objective: To determine if continuous glucose monitor (CGM)-derived glycemic patterns can characterize pregnancies with GDM as diagnosed by standard oral glucose tolerance test at 24-28 weeks’ gestation compared to those without GDM. Research Design and Methods: The analysis includes 768 individuals enrolled from two sites prior to 17 weeks’ gestation between June 2020 and December 2021 in a prospective observational study. Participants wore blinded Dexcom G6 CGM throughout gestation. Main outcome of interest was a diagnosis of GDM by oral glucose tolerance test (OGTT). Glycemic levels in participants with GDM vs. without GDM were characterized using CGM-measured glycemic metrics. Results: Participants with GDM (n=58 [8%]) had higher mean glucose (109±13 vs. 100±8 mg/dL [6.0±0.7 vs. 5.6±0.4mmol/L], p<0.001), greater glucose standard deviation (23±4 vs. 19±3 mg/dL [1.3±0.2 vs. 1.1±0.2mmol/L], p<0.001), less time in range 63-120 mg/dL (3.5-6.7mmol/L) (70% ± 17% vs. 84% ± 8%, p<0.001), greater % time >120 mg/dL (>6.7mmol/L) (median 23% vs. 12%, p<0.001), and greater % time >140 mg/dL (>7.8mmol/L) (median 7.4% vs. 2.7%, p<0.001) than those without GDM throughout gestation prior to OGTT. Median percent time >120 mg/dL (>6.7mmol/L) and time >140 mg/dL (>7.8mmol/L) were higher as early as 13-14 weeks’ gestation (32% vs. 14%, p<0.001, and 5.2% vs. 2.0%, p<0.001, respectively) and persisted during the entire study period prior to OGTT. Conclusions: Prior to OGTT at 24-34 weeks’ gestation, pregnant individuals who develop GDM have higher CGM-measured glucose levels and more hyperglycemia compared to those who do not develop GDM.


Study funding was provided by The Leona M. and Harry B. Helmsley and UnitedHealth Group. Dexcom provided the devices used in the study.


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