Performance and Safety of a Continuous Glucose Monitoring System in Pregnant Women With Gestational Diabetes Mellitus: A Multicenter, Open-Label Trial

BACKGROUND: Continuous glucose monitoring (CGM) is increasingly important in pregnancies complicated by diabetes, where strict glycemic control is essential to prevent adverse outcomes such as fetal macrosomia and preterm birth. In gestational diabetes mellitus (GDM)-which accounts for most of the diabetes in pregnancy-maternal hyperglycemia is the primary clinical concern. This study evaluated the accuracy and safety of a factory-calibrated CGM system over 15 days in pregnant women with diabetes, with most having GDM. METHODS: This prospective, multicenter, open-label trial enrolled 60 pregnant women (95% GDM, 3.3% type 1 diabetes, 1.7% type 2 diabetes). Each participant wore 2 sensors simultaneously, 1 on each upper arm, for up to 15 days. Venous blood glucose reference values were obtained using a Biosen C-line GP+ analyzer. Accuracy was assessed by 20/20% agreement rate, Diabetes Technology Society (DTS) error grid analysis, and mean absolute relative difference (MARD). Safety and usability were also evaluated. RESULTS: A total of 2901 matched CGM-reference pairs were analyzed (1451 from left-arm sensors, 1450 from right-arm sensors). The 20/20% agreement rate was 96.6% (95% CI, 95.6%-97.5%) for the left arm and 96.8% (95% CI, 95.8%-97.7%) for the right arm. The overall MARD was 7.72% (95% CI, 7.33%-8.11%) for the left arm and 7.66% (95% CI, 7.27%-8.05%) for the right arm. CONCLUSION: The CGM system demonstrated accurate, stable, and safe glucose monitoring over 15 days in pregnant women with predominantly GDM. Its strong performance supports its utility as a reliable tool for glucose monitoring during pregnancy.