Continuous Glucose Monitoring and Glycemic Patterns in Pregnant Women with Gestational Diabetes Mellitus

Background: Continuous glucose monitoring (CGM) could detect certain patterns of hyperglycemia at different times of the day that may help predict the development of maternal-fetal complications and the probability of needing pharmacological treatment. Methods: This study prospectively examined 77 women with gestational diabetes mellitus (GDM) who were placed on a CGM system for 6 days after diagnosis between 26 and 32 weeks of gestation. Patterns of hyperglycemia before meals (period of time of an hour just before meal) (>95 mg/dL), after meals (time interval of 2 h and half just after meal) (>140 mg/dL), and overnight (0-7 am) (>120 mg/dL) and their association with maternal-fetal complications and pharmacological treatment were analyzed. Receiver operating characteristic curves were developed to estimate the validity of the various patterns in detecting the need for pharmacological treatment. Results: A statistically significant relationship was observed between time in hyperglycemia after lunch and macrosomia (P = 0.035) and large for gestational age infants (P = 0.010). Pharmacological treatment was required for patients with time above range (TAR; P = 0.006) and those with hyperglycemia patterns before breakfast (P < 0.001), after breakfast (P = 0.006), before dinner (P = 0.012), and overnight (P = 0.001). Every additional percentage point of TAR was associated with a 24% increase in the probability of pharmacological treatment. Conclusions: The use of CGM for the diagnosis of GDM allows the identification of those patients who would benefit from closer monitoring during pregnancy, including self-monitoring of both pre- and postprandial blood glucose levels, facilitating the initiation of early pharmacological treatment.