Real-time continuous glucose monitoring in pregnancies with gestational diabetes: a randomized controlled trial

Objective: Compare the efficacy of real-time CGM (intervention) with capillary blood glucose (CBG: control) monitoring alone to achieve greater percent glucose time-in-range (TIR) among pregnant individuals diagnosed GDMResearch Design and Methods: Open label, single center, randomized controlled trial of pregnant individuals with GDM and ≥20 weeks gestation. Subjects were randomly assigned (2:1) to use real-time CGM plus adjunctive CBG vs CBG alone for glucose monitoring. The intervention group was instructed on the continuous use of the Dexcom G6 CGM system from enrollment to admission for delivery. The control group used CBG monitoring 4 times per day and placed a blinded CGM approximately every 20 days throughout the study period. The primary outcome was the CGM glucose percent TIR defined as 60-140 mg/dL (3.3-7.8 mmol/L) from study enrollment until hospital admission for delivery.Results: 111 subjects were enrolled between February 2021 and June 2023 (n=74 intervention; n=37 control) with no statistical differences in demographic characteristics between the groups. The CGM group had significantly higher percent glucose TIR (93.4 ± 6.1 vs 87.6 ± 13.7 in 60-140 mg/dL, P=0.027). Among key secondary CGM metric outcomes, the intervention group had significantly higher daytime TIR with lower 24-hr and daytime mean glucose and percent time above 140 mg/dL compared to the control group.Conclusions: We demonstrated a significantly higher percent glucose TIR using real-time CGM compared to CBG glucose monitoring among pregnant people with GDM. Future studies are needed to determine if achieving lower CGM glucose levels can improve perinatal and neonatal outcomes.