AMINO-ACIDS, GLUCOSE AND LACTATE CONCENTRATIONS IN UMBILICAL-CORD BLOOD IN RELATION TO UMBILICAL ARTERY FLOW PATTERNS

Objective: To study possible relationships between abnormal placental perfusion, hypoxemia and impaired fetal nutrient supply. Study design: Umbilical artery flow velocity waveforms were assessed in high risk pregnancies and compared with controls. Three groups were studied. In group I (n = 13) the pulsatility index (PI) was within normal limits, in group II (n = 9) PI was > 2 S.D. in the presence of positive end diastolic velocities and in group III (n = 13) end diastolic velocities were absent. pH and Po-2 levels and concentrations of amino acids, glucose and lactate were measured in umbilical blood obtained at cesarean section (n = 35). Results: An inverse correlation was found between concentrations of essential amino acids concentrations and the pulsatility index in the umbilical artery (P = 0.03). No correlation with hypoxemia was found (P = 0.32). The glycine/valine ratio was significantly increased in the groups with abnormal Doppler velocity indices (P = 0.02). Glucose concentrations were significantly reduced in the case of absent end diastolic velocities (P = 0.001). No significant differences were found between the three groups concerning lactate concentrations and acid-base balance parameters. Conclusions: These findings, especially the increased glycine/valine ratio, which is characteristic for kwashiorkor, indicate that abnormal placental perfusion is associated with impaired fetal nutrient supply, in the presence of a normal fetal oxygenation.