Concentrations of hypoxanthine, xanthme, undine and urate in amniotic fluid at caesarean section and the association of raised levels with prenatal risk factors and fetal distress

Summary. Samples of amniotic fluid were obtained at caesarean section from 33 of 80 consecutive unselected patients in whom the membranes were intact. Concentrations of the ATP metabolites, hypoxanthine and xanthine, as well as uridine and urate were determined using high pressure liquid chromatography. Independent ‘clinical’ factors associated with reduced fetal growth and well‐being were identified and the patients were assigned to one of three groups: those with no recognized risk, those with moderate risk and a small group of four patients with high risk. The mean hypoxanthine concentration was higher in the moderate‐risk group than in the group with no risk. Two of the three patients with proteinuric hypertension in the high‐risk group had normal hypoxanthine concentrations. There were seven patients with fetal distress, and concentrations of hypo xanthine, xanthine, uridine and urate were significantly higher in the three patients who had meconium stained amniotic fluid in addition to abnormal fetal heart rate tracings than in the remaining four who had fetal heart rate abnormalities only. It is suggested that fetal distress at emergency caesarean sections might be quantitated by such analysis.