Continuous Glucose Monitoring in Gestational Diabetes Mellitus: Evidence, Clinical Benefits and Remaining Challenges

Use of continuous glucose monitoring (CGM) technology has contributed to significant improvements in the care of women with pregestational type 1 diabetes (T1D), including for preconception management of glycemia. Increasingly, it is being recommended for use in women with type 2 diabetes (T2D) to achieve similar goals. Gestational diabetes mellitus (GDM) is a complication of pregnancy in women without dysglycemia prior to conception, and the use of CGM in this group is limited and is now only beginning to accumulate evidence. This growing evidence base indicates that the use of CGM can be associated with reductions in adverse pregnancy outcomes for women with GDM and their infants. These include reduced large for gestational age (LGA) offspring, fewer infants with macrosomia, reduced admissions to neonatal intensive care units (NICU), and fewer Cesarean section deliveries. Use of CGM has also been associated with earlier prediction of GDM risk and earlier detection of GDM, potentially enabling earlier glycemic management. The range of CGM-derived metrics that can be applied in the management of women with GDM includes sensor-detected average glucose, time in range (TIR), time above range (TAR), time below range (TBR) and glycemic variability (GV). However, to date, no specific CGM targets for these metrics have been agreed. In this narrative review, we identify the clinical evidence that supports the use of CGM and CGM metrics of glucose control in women with GDM and indicate CGM targets that may have value in this important group. We also provide practical insights on how CGM devices can be used to understand daily and weekly glucose trends, thereby optimising glycemia during and after a pregnancy with GDM.