Continuous glucose monitoring versus self-monitoring of blood glucose in the treatment of gestational diabetes mellitus

ObjectiveTo compare Continuous Glucose Monitoring System (CGMS®) with self-monitoring of plasma glucose (SM) in detecting patients with gestational diabetes mellitus (GDM) needing antidiabetic drug treatment.Research design and methodsPregnant women at 22–34 gestational weeks had at least two abnormal high values out of three in OGTT. Patients were randomly allocated to have CGMS® (n = 36) or SM (n = 37). Dietary counselling was similar in both groups. Patients tested their plasma glucose 5 times per day. Need of antidiabetic treatment was determined using the following cut-off values: fasting plasma glucose >5.5 mmol/L twice or >5.5 mmol/l once and postprandial value > 7.8 mmol/l, or postprandial value at least twice above 7.8 mmol/l.ResultsIn 11 out of 36 patients (31%) monitored with CGMS® antihyperglycemic drug therapy was introduced (8/36 insulin only, 2/36 metformin only, 1/36 insulin + metformin) whereas only 3/37 (8%) in the self-monitoring group were drug-treated (difference between groups, p = 0.0149). There were no statistically significant differences between the groups regarding maternal age, pre-pregnancy BMI, HbA1c, gestational weeks at delivery, rate of pregnancy-induced hypertension, rate of caesarean section, infant birth weight or neonatal hypoglycaemia.ConclusionsContinuous glucose monitoring system detects a markedly higher proportion of GDM mothers needing antihyperglycemic medication compared with self-monitoring of plasma glucose. Further large-scale studies are needed to evaluate whether CGMS® guided initiation of antihyperglycemic therapy results in less macrosomia and perinatal complications related to GDM.