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Am J Perinatol 2025; 42(05): 555-563
DOI: 10.1055/a-2419-8476
SMFM Fellowship Series Article

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

Jia Jennifer Ding 
1   Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, Connecticut
,
Lauren Milley
2   Donald and Barbara Zucker School of Medicine, Hofstra/Northwell, Hempstead, New York
,
Moeun Son
3   Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York
› Author Affiliations Funding This study was supported by the internal departmental funding.
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Abstract

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.

Keywords

maternal hypoglycemia - neonatal morbidity - continuous glucose monitoring

Note

Dexcom Inc. provided 6th generation continuous glucose monitors at subsidized cost but had no input in the design of the study, data analysis or interpretation, or manuscript writing.


Supplementary Material



Publication History

Received: 22 April 2024

Accepted: 20 September 2024

Article published online:
16 October 2024

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