Is the difference in neonatal blood glucose concentration of caesarian and vaginally delivered term infants requiring separated reference intervals?

Background: Mode of delivery has been reported to affect the cord blood glucose level of newborns. Vaginally delivered (VD) newborns were found to have relatively increased concentration of cord blood glucose than those delivered by cesarean section (CS). The aim of this study is thus to determine whether the difference in cord blood glucose concentration among VD and CS newborns is necessitating partitioned reference intervals (RIs) for the laboratory diagnosis of neonatal hypoglycemia.

Methods: A total of 60 newborns were included from Tikur Anbessa Specialized Hospital (TASH). Cord blood samples were collected and analyzed for glucose by Glucose-oxidase (GOD-PAP) method in TASH laboratory using HumaStar 300 from November 2010 to April 2011. All pre-analytical, analytical and post-analytical aspects were thoroughly controlled. A robust method was used for the determination of reference intervals using MedCalc® software Version 11.6.1.

Results: VD newborns accounted for 71.7% (n = 43) while the CS newborns accounted for 28.3% (n = 17). No statistically significant difference was noted in the studied demographic variables among VD and CS newborns except for blood glucose level. The RIs were then determined to be 2.46-6.85 mmol/l and 2.46-5.04 mmol/l for VD and CS newborns respectively. The combined RI was 2.24-6.48 mmol/l.

Conclusion: Combined RI better be used for the interpretation of cord blood glucose values in VD and CS newborns. Cord blood glucose concentrations of 2.24 mmol/l can be used as statistical estimates of cut off points for neonatal hypoglycemia in newborns irrespective of their mode of deliveries.