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Updated: Oct 8, 2025
Spinal Cord Electrophysiology
Published on: January 18, 2010
Cord-Blood Derived Chemistry Reference Values in Preterm Infants for Sodium, Chloride, Potassium, Glucose, and
Amelie Stritzke1,2,3, Rana Ismail1, M Sarah Rose4
1Section of Neonatology, Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Canada.
Insights
Neonatal cord blood electrolyte and glucose levels change with gestational age. Preterm infants show higher potassium and chloride levels than term infants, impacting neonatal care.
Area of Science:
- Neonatal physiology
- Pediatric endocrinology
- Clinical chemistry
Background:
- International guidelines advocate for maintaining normal serum electrolytes in preterm infants.
- Term infant cord blood values can differ based on pregnancy pathology.
Purpose of the Study:
- To establish maturity-related reference intervals for cord blood electrolytes, glucose, and creatinine.
- To investigate associations between these analytes and gestational age, delivery mode, and other factors.
- To compare preterm cord blood values with term and adult reference ranges.
Main Methods:
- Analysis of cord blood samples from 591 infants (537 preterm, 54 term) for sodium, chloride, potassium, glucose, and creatinine.
- Statistical examination of associations with gestational age, delivery mode, multiple births, and SGA.
- Comparison of preterm cord values to term and adult reference intervals.
Main Results:
- Cord blood sodium, chloride, and creatinine increased with gestational age (GA) in preterm infants, while glucose remained steady.
- Preterm infants had higher average cord potassium and chloride levels compared to term infants.
- Significant differences were observed between preterm cord reference intervals and adult reference values for chloride, creatinine, potassium, and sodium.
- Delivery mode, multiple births, and SGA were associated with variations in cord blood analytes.
Conclusions:
- Neonatal cord blood electrolyte, creatinine, and glucose values exhibit variability across gestational age.
- Preterm cord blood potassium and chloride levels are notably higher than those in term infants.
- Deviations in cord reference values based on delivery mode, growth status, and multiple births have direct implications for neonatal care and fluid management strategies.
Objective:
International guidelines recommend that preterm infants should be supported to maintain their serum electrolytes within "normal" ranges. In term babies, cord blood values differed in pathological pregnancies from healthy ones.
Study Design:
We examined cord blood sodium, chloride, potassium, glucose, and creatinine to derive maturity-related reference intervals. We examined associations with gestational age, delivery mode, singleton versus multiple, and prenatal maternal adverse conditions. We compared preterm cord values to term, and to adult reference ranges.
Results:
There were 591 infants, 537 preterm and 54 term. Preterm cord glucose levels were steady (3.7 ± 1.1 mmol/L), while sodium, chloride, and creatinine increased over GA by 0.17, 0.14 mmol/L/week, and 1.07 µmol/L/week, respectively (p < 0.003). Average preterm cord potassium and chloride were higher than the term (p < 0.05). Compared with adult reference intervals, cord preterm reference intervals were higher for chloride (100-111 vs. 98-106 mmol/L), lower for creatinine (29-84 vs. 62-115 µmol/L), and more variable for potassium (2.7-7.9 vs. 3.5-5.0 mmol/L) and sodium (130-141 vs. 136-145 mmol/L). Cesarean section was associated with higher potassium and lower glucose, multiple births with higher chloride and creatinine and lower glucose, and SGA with lower glucose.
Conclusion:
Cord blood values varied across the GA range with increases in sodium, chloride, and creatinine, while glucose remained steady. Average preterm reference values were higher than term values for potassium and chloride. Preterm reference values differed from published adults' reference values. The changes across GA and by delivery mode, SGA, and being a multiple, which may have direct implications for neonatal care and fluid management.
Key Points:
· Cord blood electrolyte, creatinine, and glucose values vary across neonatal gestational age.. · Average preterm cord values of potassium and chloride were higher than term values.. · Cord reference values differ by delivery mode, growth, and multiple impacting neonatal care decisions..
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