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Poster Session 2

Category: Diabetes

Poster Session 2

(403) Comparing CGM fasting blood glucose versus time in range as predictors of neonatal hypoglycemia

Wednesday, February 11, 2026

3:30 PM - 5:00 PM

Submitting Author and Presenting Author(s)

Alesandra Rau, MD

Resident Physician
UC Irvine Medical Center
Orange, California, United States

Coauthor(s)

Genevieve Mazza, MD

Fellow Physician
UC Irvine Medical Center
Orange, California, United States
Megan C. Oakes, MD, MSCI (she/her/hers)

Maternal-Fetal Medicine
MemorialCare Miller Children’s and Women’s Hospital
Long Beach, California, United States

Objective:
Neonatal hypoglycemia is a common manifestation of sub-optimally controlled gestational diabetes requiring medication (A2GDM) and type 2 diabetes mellitus (T2DM). Traditional guidance for strict glycemic control in pregnancy, with a fasting blood glucose (FBG) goal < 95 mg/dL, reduces this complication. A continuous glucose meter (CGM) time in range (TIR) >70% is also associated with improved neonatal outcomes in patients with T1DM. As continuous glucose meters (CGM) are utilized more frequently in patients with A2GDM and T2DM, it is unclear which parameter is the strongest predictor of adverse outcomes. We aimed to compare predictive characteristics of mean FBG >95 mg/dL to TIR < 70% for neonatal hypoglycemia in patients using CGM.

Study Design:
This was a retrospective cohort study of patients with T2DM or A2GDM using a CGM in the 3rd trimester between January 2021 and May 2025. Mean 3^rd trimester BG at 6AM was used as a proxy for FBG. The cohort was grouped by FBG <95 or >95 mg/dL and TIR >70% or < 70%. Area under the receiver operator curves (AUROC) were generated to compare the predictive abilities of FBG >95 versus TIR < 70% as predictors of neonatal hypoglycemia (defined as neonatal BG < 40 mg/dL within the first 24h of life). Predictive characteristics were compared between the groups.

Results:
Of 133 patients in the cohort, 108 (82.4%) had mean FBG >95 mg/dL and 47 (35.6%) had TIR < 70%. The AUROC for FBG >95 mg/dL was not significantly different compared to TIR < 70% for the prediction of neonatal hypoglycemia (0.56 (95% CI 0.54-0.72) and 0.63 (95% CI 0.50-0.63), respectively; p=0.15) (Figure 1). Compared to TIR < 70%, FBG >95 had higher positive predictive value and accuracy; however, the positive likelihood ratio was weak (Table 1).

Conclusion:
Among those with A2GDM and T2DM using a CGM, 3^rd trimester mean FBG >95 mg/dL and TIR < 70% are poor predictors of neonatal hypoglycemia. As utilization of CGMs increases for this patient population, larger studies are needed to identify which parameters most strongly reduce adverse neonatal outcomes.