Umbilical Cord Blood Gas not associated with transitional Neonatal Hypoglycemia: JAMA
Researchers have found in a new prospective cohort study that there was no significant association between UCBG parameters and subsequent transient neonatal hypoglycemia (TNH). However, it establishes a robust, percentile-based UCBG reference dataset that may aid future research and clinical interpretation. Extremely low UCBG values could potentially indicate a higher risk of pathologic hypoglycemia, though further validation is needed. The study was published in JAMA Network Open by Marcia R. and colleagues.
Data used in the research were obtained from a period ranging from May 2020 to September 2022, where 598 neonates having gestational age not less than 35 weeks were used. For the analysis, the methodology involved the use of arterial and venous umbilical cord blood pairs immediately after birth. Neonates with incomplete data as well as those suffering from hyperinsulinism were excluded in the study. In the analyzed neonates, the median gestational age was 39 weeks (IQR, 37 weeks 6 days to 40 weeks 0 days) while males accounted for 55.5%. Through systematic collection of maternal and neonatal information coupled with glucose screening of neonates within four hours of birth, a clear framework was put in place to compare pre-birth and post-birth glucose levels.
Key findings:
- The prevalence of metabolic instability was significant in the population studied since there were 188 neonates with hypoglycemia defined as levels <45 mg/dL (31.4%) and 22 infants with severe hypoglycemia <30 mg/dL (3.7%).
- The arterial UCBG values at the time of delivery were 67 mg/dL (IQR, 58-84) while those for venous blood were 85 mg/dL (IQR, 72-102).
- This yielded median venous-arterial difference of 16 mg/dL (IQR, 10-23) and an extraction rate of 19.0%.
- Despite the significantly higher median extraction rates of 35.3% compared to 18.7%, as well as increased incidences of severe TNH of 13.6% compared to 3.3% among neonates with very low arterial UCBG values, there was no significant discriminatory power.
- ROC analyses gave a maximum area under the curve of 0.64 (95% confidence interval, 0.45-0.81).
- Therefore, no particular percentile or cut-off value could be found that would be clinically useful in terms of sensitivity and specificity.
However, from the results presented in this prospective cohort study, it can be concluded that there is no evidence of a link between UCBG characteristics and the risk of developing transitional neonatal hypoglycemia. The quest for the holy grail of an immediately available biomarker at birth to predict neonatal hypoglycemia may never materialize. Nonetheless, the findings of this study will be a good benchmark for researchers to build upon without adopting UCBG values as a substitute measure for screening.
Reference:
Roeper M, Meissner T, Friesl L, et al. Umbilical Cord Blood Glucose Concentrations and Transitional Neonatal Hypoglycemia. JAMA Netw Open. 2026;9(4):e266170. doi:10.1001/jamanetworkopen.2026.6170
