The Role of Continuous Glucose Monitoring in Clinical Decision-Making in Diabetes in Pregnancy

Abstract

Numerous studies have shown that improved glucose control in pregnancy will lessen both maternal and fetal complications, but adverse outcomes remain more frequent in diabetic than in nondiabetic pregnancies. Complications increase with the degree of glucose intolerance. The continuous glucose monitoring system (CGMS) can provide a glucose profile over 72 hours. It consists of a disposable glucose-sensing device that is placed just beneath the skin and connects by cable to a pager-size glucose monitor. Interstitial-fluid glucose levels are estimated at 10-second intervals and averaged every 5 minutes. Pregnant women with diabetes were offered the CGMS in the setting of standard diabetes care. Its accuracy was determined by comparing the readings with patient's finger-prick glucose readings. Sixty-eight CGMS traces were obtained in 55 pregnant women: 37 with gestational diabetes, 10 with type 2 diabetes, and 8 with type 1 diabetes. Forty-two CGMS traces, 62% of the total, provided information beyond that available from the patients' home glucose monitoring diary. Examples include undetected postprandial hyperglycemia and overnight hypoglycemia. The CGMS was generally most helpful in women with type 1 diabetes, in whom all but 2 of 18 studies yielded additional information. More than three-fourths of women responding to a questionnaire expressed a belief that the benefits of the CGMS outweigh its inconvenience. All but 4 of 48 participants found the CGMS to be easy to use. In addition, 90% of respondents felt that they had a better understanding of how to control blood glucose since using the CGMS. In this community-based cohort study, these investigators found the CGMS to be of substantial help in managing preexisting and gestational diabetes in pregnant women. By adding information to that available from finger-prick monitoring, it may help clinicians to optimize glycemic control and prevent hypoglycemia.