A Pilot Study Using Continuous Glucose Monitoring among Patients with a Low 1-Hour Glucose Challenge Test Result versus Controls to Detect Maternal Hypoglycemia.

Objective:  A low 1-hour glucose challenge test (GCT) result (<10th percentile for population) has been associated with neonatal morbidity, including small-for-gestational-age birth weight, and it is hypothesized that underlying maternal hypoglycemia may contribute to this neonatal morbidity. We sought to assess whether eligible patients would undergo continuous glucose monitoring to allow comparison of maternal hypoglycemia between those with a low GCT result versus controls.

Study design:  This exploratory study enrolled patients who completed a GCT between 24 and 30 weeks' gestation from June to September 2022. English- or Spanish-speaking participants aged ≥18 years wore a blinded continuous glucose monitor (CGM) for 10 days. There were 10 participants each in the low GCT (<82 mg/dL) and normal GCT group. Proportions were calculated to determine recruitment rates and describe the low versus normal glycemic groups across clinical and sociodemographic characteristics. Maternal hypoglycemia, defined using various proposed thresholds, was analyzed as continuous data (time duration) with Student's t-tests and categorical data (number of episodes) with chi-square tests and bivariate analyses were performed comparing participants with a low versus normal GCT. Primary outcome measures were recruitment, enrollment, and adherence rates, and overall glycemic values for each group.

Results:  Of 64 eligible patients, 58 (91%) were approached, and of them, 20 (35%) were enrolled. All 20 participants had CGM data to review with 100% adherence. Average glucose values were similar between participants in the low GCT and normal GCT groups (111.7 ± 18.0 vs. 111.6 ± 11.7 mg/dL, p = 0.99), and participants with a low GCT value did not demonstrate more hypoglycemia than those with a normal GCT value across five proposed thresholds on CGM analysis.

Conclusion:  In this pilot study, participants wore blinded CGMs to collect glycemic data, and those with a low GCT result did not experience more hypoglycemia than those with a normal GCT on CGM analysis.

Key points: · Study participants wore continuous glucose monitors in blinded mode to gather glycemic data with 100% adherence.. · Participants with a low GCT result (<82 mg/dL) as compared with those with a normal GCT result were not more likely to demonstrate maternal hypoglycemia using several thresholds on CGM analysis.. · In our cohort, there were few participants in either glycemic group who reported food insecurity or lived in a food desert..