Usefulness of Glucose Monitoring in Neonates of Mothers With an Elevated Glucose Challenge Test and a Normal Oral Glucose Tolerance Test

Background Neonatal hypoglycemia is a common metabolic disturbance in neonates. Glucose monitoring is recommended for certain groups of neonates, including those whose mothers have pre-gestational or gestational diabetes. Little is known about the relevance of glucose monitoring in neonates whose mothers have an elevated screening glucose challenge test (GCT) but a normal oral glucose tolerance test (OGTT). Objectives The objectives of this study were to determine if neonates of mothers with an elevated GCT but a normal OGTT had hypoglycemia and to establish if there was an association between the maternal GCT and neonatal blood glucose level. Methods A single-site retrospective analysis was conducted on 307 neonates born in a community hospital in the Brooklyn area of New York between November 1, 2021, and November 1, 2023, who were identified as being at risk for hypoglycemia due to known risk factors like maternal diabetes, prematurity, low birth weight, and small or large size for gestational age, as well as possible risk factors like an elevated maternal GCT but a normal OGTT. Glucose monitoring had been done for these neonates at birth per AAP recommendations. The Office of Science and Research Institutional Review Board reviewed the study which was determined to meet the criteria for exemption. The individual authorization requirements were waived and adequate steps were taken to ensure data privacy. Neonates of diabetic mothers or mothers with an elevated OGTT and neonates who were born preterm, low birth weight, and small or large for gestational age were excluded from the study while neonates whose mothers had an elevated GCT, but a normal OGTT were included. This brought to 63 the number of neonates who met the inclusion criteria. Charts were reviewed to see if these neonates had hypoglycemia during the course of glucose monitoring. The chi-square test was used for categorical variables and the two-sample <i>t-</i>test was used for continuous variables. Results In our study, eight of the 63 neonates had asymptomatic hypoglycemia while the rest were euglycemic. None required admission to the neonatal intensive care unit and the hypoglycemia resolved with oral feed, oral glucose gel, or a combination of the two. Although hemoglobin A1c was also elevated in eight of the 63 mothers, all the mothers of the neonates with hypoglycemia had normal hemoglobin A1c, and no relationship was found between the hypoglycemic reaction (X² = 0.927) and hemoglobin A1c in the mothers who had an elevated GCT but a normal OGTT. The male-to-female ratio was approximately 1:1, and there was no relationship between gender and neonatal hypoglycemic reaction (X² = 0.002). There was also no correlation between maternal GCT and initial (r=-0.173) or lowest (r=-0.182) neonatal glucose readings. Conclusion Our study demonstrated that the likelihood of hypoglycemia in neonates of mothers with an abnormal GCT, but a normal OGTT was slim. Further studies are needed, and a larger group size would be of benefit.