The Effect of Real-Time Continuous Glucose Monitoring in Pregnant Women With Diabetes

Abstract

OBJECTIVETo assess whether intermittent real-time continuous glucose monitoring (CGM) improves glycemic control and pregnancy outcome in unselected women with pregestational diabetes.RESEARCH DESIGN AND METHODSA total of 123 women with type 1 diabetes and 31 women with type 2 diabetes were randomized to use real-time CGM for 6 days at 8, 12, 21, 27, and 33 weeks in addition to routine care, including self-monitored plasma glucose seven times daily, or routine care only. To optimize glycemic control, real-time CGM readings were evaluated by a diabetes caregiver. HbA1c, self-monitored plasma glucose, severe hypoglycemia, and pregnancy outcomes were recorded, with large-for-gestational-age infants as the primary outcome.RESULTSWomen assigned to real-time CGM (n = 79) had baseline HbA1c similar to that of women in the control arm (n = 75) (median 6.6 [range 5.3–10.0] vs. 6.8% [5.3–10.7]; P = 0.67) (49 [34–86] vs. 51 mmol/mol [34–93]). Forty-nine (64%) women used real-time CGM per protocol. At 33 weeks, HbA1c (6.1 [5.1–7.8] vs. 6.1% [4.8–8.2]; P = 0.39) (43 [32–62] vs. 43 mmol/mol [29–66]) and self-monitored plasma glucose (6.2 [4.7–7.9] vs. 6.2 mmol/L [4.9–7.9]; P = 0.64) were comparable regardless of real-time CGM use, and a similar fraction of women had experienced severe hypoglycemia (16 vs. 16%; P = 0.91). The prevalence of large-for-gestational-age infants (45 vs. 34%; P = 0.19) and other perinatal outcomes were comparable between the arms.CONCLUSIONSIn this randomized trial, intermittent use of real-time CGM in pregnancy, in addition to self-monitored plasma glucose seven times daily, did not improve glycemic control or pregnancy outcome in women with pregestational diabetes.

Seventy two-hour glucose monitoring profiles in mild gestational diabetes mellitus: differences from healthy pregnancies and influence of diet counseling

“…However, current glucose targets for both the diagnosis and treatment of GDM patients still do not have normalized perinatal outcomes (15,16). By way of the 72-h CGM, we were able to assess glucose profiles during the third trimester of GDM patients, as defined by IADPSG (6), and compare them to those of matched controls.…”

“…However, the authors caution that the flattening of glucose variability here observed in the GDM2 group related to dietary counseling might not be enough to favorably affect perinatal outcomes in all patients, due to the importance of other confounders besides glucose, such as obesity, lipids, cytokines, among others (22,23). Future studies should possibly address these changes in the same patients, before and after dietary counseling, although we recognize that it could limit the patient sample according to the protocol (16). Studies conducted on groups at high risk of diabetes, such as other mild or subclinical glucose metabolism disorders, have also observed differences in CGM glucose parameters, suggesting that glucose variability and levels above predefined thresholds seem to be the earliest detectable glucose abnormalities within the range of carbohydrate metabolism disorders (24,25).…”

Long-term Cognitive Implications of Intrauterine Hyperglycemia in Adolescent Offspring of Women With Type 1 Diabetes (the EPICOM Study)

“…An HbA 1c level in pregnancy ,7% (53 mmol/mol) was considered acceptable; thus, HbA 1c levels in our cohort were higher than we would expect today (31). In a Danish study using cognitive scores at conscription, HbA 1c was negatively associated with offspring cognitive function, but when HbA 1c levels were ,7% (53 mmol/mol) cognitive function was the same as in control subjects (23).…”

CGM, Pregnancy, and Remote Monitoring

“…29 The Danish study of intermittent real-time CGM (rtCGM) found no differences in outcomes between groups; however, only 64% (49/76) in the rtCGM group followed the protocol. 30,31 Taken together, these studies suggest that adjunctive CGM use may help make decisions about therapy, but improvement of long-term glucose control and outcomes may require more than just intermittent use.…”