Postpartum Continuous Glucose Monitoring to Detect Dysglycemia After Gestational Diabetes

Background: Up to one-third of people with gestational diabetes (GDM) will have persistent dysglycemia, and more than half do not complete the recommended postpartum oral glucose tolerance test (OGTT). This study assessed the use of blinded postpartum continuous glucose monitoring (CGM) to detect dysglycemia by assessing return rates, participant experience, and power to predict OGTT results. Method: Blinded CGM was placed on postpartum day 1 to 3 before discharge from the hospital and again at six weeks after pregnancy complicated by GDM and worn at home for up to 10 days. Participants mailed the CGM back and were encouraged to undergo standard of care six-week OGTT. Results: Fifty women (36 ± 6 years old; 40% non-Hispanic white, 24% non-Hispanic black, 22% Asian, 14% Hispanic; 34% Medicaid insured) were consented. First CGM was completed by 86%, second CGM was completed by 60%, and postpartum OGTT was performed by 68%. Mean first sensor glucose was 121.8 ± 14.1 mg/dL. Dysglycemia on OGTT was diagnosed in seven participants: six with impaired glucose tolerance (18%) and one with diabetes (3%). Percent time <96% in the range 70 to 180 mg/dL predicted abnormal OGTT with positive predictive value of 54% and negative predictive value of 100%. The sensitivity and specificity of CGM to predict postpartum dysglycemia were 100% and 78%, respectively. If given a choice, 94% of participants would prefer CGM over OGTT. Conclusions: Postpartum CGM is a reasonable and convenient initial postpartum screen for postpartum dysglycemia with high completion rates, sensitivity, and acceptability ratings. Percent time in range 70 to 180 mg/dL had strong predictive power for OGTT.