The role of continuous glucose monitoring in clinical decision-making in diabetes in pregnancy

Background: The continuous glucose monitoring system (CGMS) is a novel tool to assess 24-h glucose fluctuations. In pregnancies complicated by diabetes, where excellent glucose control is desired to improve maternal and fetal outcomes, CGMS may have a role in fine-tuning management. Aims: To assess the usefulness of CGMS in pregnant women with diabetes for medical decision-making and to evaluate patient tolerability and perception of usefulness. Methods: Pregnant women with diabetes at the Werribee Mercy Hospital were offered CGMS in the setting of their standard diabetes care. Treating clinicians were asked if the CGMS altered management decisions from those based on conventional glucose monitoring. The accuracy of the CGMS was assessed by comparison with the patients' finger-prick glucose readings. Patients completed a feedback questionnaire after having the CGMS and viewing their results. Results: CGMS traces (n = 68) were obtained in 55 pregnant women - 37 with gestational diabetes, ten with type 2 and eight with type 1 diabetes. Forty-two of 68 (62%) traces were assessed as providing additional information which altered clinical management decisions. This included showing undetected postprandial hyperglycaemia and overnight hypoglycaemia. Subject feedback was generally positive, with 37 of 48 (77%) respondents reporting that the benefits of the CGMS outweighed the inconvenience. Conclusion: CGMS is a well-tolerated clinically useful tool in the management of gestational diabetes and pre-existing diabetes in pregnancy.