Fetal umbilical cord blood erythropoietin, interleukin-6, pH, pO(2), pCO(2), and base excess levels in histologic and/or clinical chorioamnionitis: is the response only inflammatory?

OBJECTIVE: To determine the correlation of histological chorioamnionitis (CA) with and without clinical CA with umbilical cord blood gases, erythropoietin (EPO), and interleukin-6 (IL-6) levels.

METHODS: Umbilical artery blood gas analysis (pH, pO(2), pCO(2), BE) and umbilical vein EPO and IL-6 levels were measured in 202 infants from normal, histological, and no clinical CA and histological plus clinical CA pregnancies.

RESULTS: Umbilical artery blood gas analyses were not different between normal controls and histological and clinical CA groups. Blanc Stage 1 histological CA had no abnormal EPO or IL-6 umbilical blood results. EPO in umbilical venous blood was elevated only in those infants with both histological and clinical CA. Umbilical vein IL-6 levels were elevated in all advanced microscopic and clinical CA. High and low EPO groups also have corresponding high and low IL-6 levels suggesting a common stimulus for these substances.

CONCLUSIONS: Blanc stage I histological CA is probably clinically insignificant. CA is infrequently associated with abnormal umbilical artery blood gas levels. Advanced histological and clinical CA can elevate both EPO and IL-6 in umbilical blood and these may be key elements of mechanisms that effect fetal brain function.