Evidence-Based CGM Targets to Improve Maternal and Neonatal Health in Diabetic Pregnancies

A retrospective cohort study conducted at a U.S. tertiary center between 2018 and 2021 sought to assess the association between continuous glucose monitoring (CGM) metrics and perinatal outcomes to identify optimal targets for mitigating morbidity. The study was published in Diabetes Care.

The study focused on pregnant patients with type 1 or type 2 diabetes who used real-time CGM and delivered at the designated center. The cohort excluded cases of multiple gestations, fetal anomalies, and early pregnancy loss. Various CGM metrics were assessed, including time in range (TIR; 65-140 mg/dL), time above range, time below range (TBR), glucose variability, average glucose, and the glucose management indicator.

The primary outcome comprised a composite of fetal or neonatal mortality, infants classified as large or small for gestational age at birth, neonatal intensive care unit admissions, instances of hypoglycemia, shoulder dystocia or birth trauma, and hyperbilirubinemia. Logistic regression was employed to evaluate the association between CGM metrics and these outcomes, leading to the determination of optimal TIR.

The study cohort consisted of 117 patients, of whom 16 (13.7%) had been using CGM before pregnancy, and 68 (58.1%) had type 1 diabetes. Overall, 83.8% of the patients experienced the composite neonatal outcome, emphasizing the significance of achieving optimal glucose control during pregnancy.

All CGM metrics, with the exception of TBR, exhibited associations with neonatal morbidity. Specifically, for every 5 percentage-point increase in TIR, the odds of neonatal morbidity decreased by 28% (odds ratio, 0.72; 95% CI, 0.58-0.89). This led to the identification of an optimal TIR range, specifically between 66% and 71%.

The investigators concluded, “Nearly all CGM metrics were associated with adverse neonatal morbidity and mortality and may aid management of preexisting diabetes in pregnancy. Our findings support the American Diabetes Association recommendation of 70% TIR.”