Continuous glucose monitoring for the evaluation of gravid women with type 1 diabetes mellitus

OBJECTIVE: To compare the daily glycemic profile reflected by continuous and intermittent blood glucose monitoring in pregnant women with type 1 diabetes and to compare the treatment protocols based on the two monitoring methods. METHODS: The study sample consisted of 34 gravid patients at gestational weeks 16-32, with type 1 diabetes being treated by multiple insulin injections. Data derived from the continuous glucose monitoring system for 72 hours were compared with fingerstick glucose measurements performed 6-8 times per day. During the study period, patients documented the time of food intake, insulin injections, and hypoglycemic events. Data on demographics, gravidity, parity, body mass index, hemoglobin A1c, and fructosamine levels were collected for each patient. RESULTS: An average (± standard deviation) of 780 ± 54 glucose measurements was recorded for each patient with continuous glucose monitoring. The mean total time of hyperglycemia (glucose level greater than 140 mg/dL) undetected by the fingerstick method was 192 ± 28 minutes per day. Nocturnal hypoglycemic events (glucose level less than 50 mg/dL) were recorded in 26 patients; in all cases, there was an interval of 1-4 hours before clinical manifestations appeared or the event was revealed by random blood glucose examination. Based on the additional information obtained by continuous monitoring, the insulin therapeutic regimen was adjusted in 24 patients (70%). CONCLUSION: Continuous glucose monitoring can diagnose high postprandial blood glucose levels and nocturnal hypoglycemic events that are unrecognized by intermittent blood glucose monitoring and may serve as a basis for determining treatment regimens. A large, prospective study on maternal and neonatal outcome is needed to evaluate the clinical implications of this new monitoring technique.