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The following is a summary of “Evidence for improved glucose metrics and perinatal outcomes with continuous glucose monitoring compared to self-monitoring in diabetes during pregnancy,” published in the April 2025 issue of American Journal of Obstetrics & Gynecology by Burk et al. 

Researchers conducted a retrospective study to compare continuous glucose monitoring (CGM) with self-monitoring of blood glucose (SMBG) in diabetes during pregnancy and identify glucose metrics linked to perinatal outcomes to guide treatment targets.  

They searched Medline, Embase, CENTRAL, CINAHL, and Scopus from January 2003 to August 2024. Randomized controlled trials (RCTs) and quasi-experimental studies comparing CGM with SMBG in diabetes in pregnancy (DIP) were included. Randomized controlled trials (RCTs) and quasi-experimental studies were analyzed separately. Data were extracted on CGM glucose metrics, HbA1c, cesarean delivery rates, large-for-gestational-age (LGA), small-for-gestational-age (SGA), neonatal hypoglycemia, and neonatal intensive care unit (NICU) admission. Results were summarized as mean differences (MD) or odds ratios (OR) with 95% CI and 95% prediction intervals (95% PI). Prespecified subgroup analyses were executed based on the DIP subtype and CGM duration (continuous vs intermittent) for LGA. The certainty of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework.  

The results showed that CGM compared to SMBG reduced HbA1c (MD -0.22%, 95%CI: -0.37, -0.08) across DIP (7 RCTs, moderate-certainty evidence). In type 1 diabetes (T1D), CGM throughout pregnancy lowered HbA1c (MD -0.18%, 95%CI: -0.36, 0.00) and LGA risk (OR 0.51, 95%CI: 0.28, 0.90) (1 RCT, high-certainty evidence). In gestational diabetes mellitus (GDM), intermittent CGM use reduced HbA1c (MD -0.18%, 95%CI: -0.33, -0.02) (5 RCTs, moderate-certainty evidence) and LGA risk (OR 0.46, 95%CI: 0.26, 0.81) (1 quasi-experimental study, low-certainty evidence). Data on CGM benefits in type 2 diabetes (T2D) remained insufficient. Increased pregnancy time-in-range (T1D) and lower mean sensor glucose (T1D/GDM) correlated with reduced LGA risk.  

Investigators concluded that CGM usage, compared to SMBG, reduced HbA1c and possibly LGA across DIP, with the greatest benefit observed in T1D followed by GDM, and that mean sensor glucose and pregnancy %time-in-range are important CGM metrics for reducing LGA. 

Source: ajog.org/article/S0002-9378(25)00217-0/fulltext