Effect of the mode of birth on purine and malondialdehyde levels in umbilical arterial plasma

Objective: To examine the effect of the mode of birth on plasma purine and malondialdehyde levels in normal term infants. Study Design: Umbilical arterial cord blood was obtained immediately after birth from a convenience sample of 75 normal term newborns born by either vaginal delivery (with or without oxytocin augmentation) or elective caesarian section. Plasma was analyzed for purine levels alone (n = 75) or purine and malondialdehyde levels (n = 39). Non‐parametric Kruskall‐Wallis test was utilized for nominal data, and one‐way ANOVA for numerical data. Results: While plasma hypoxanthine levels were not different between the three groups, plasma xanthine levels were significantly higher in infants born vaginally without labor augmentation. Uric acid levels were significantly elevated in those with labor‐augmented vaginal births compared to infants born by elective caesarian section (P < 0.03). A positive correlation was noted between uric acid and malondialdehyde levels (χ = 0.34, P < 0.018). Conclusion: Plasma xanthine and uric acid levels are higher in infants born by vaginal birth, compared to infants born by elective caeasarian section. Our data suggest that some degree of hypoxemia is associated with vaginal birth, resulting in rapid utilization and breakdown of adenosine triphosphate into its purine byproducts. Since all the neonates studied were normal, we speculate that this degree of hypoxia is not pathological. This research was supported in part by the Center for Health Disparities (5P20 MD001632 ) and LLU‐NIH Initiative to Maximize Student Diversity (5 R25 GM060507 ‐06).