Umbilical Cord Blood Lactate as an Indicator of Fetal Hypoxia

Objective: This study aimed to evaluate the role of umbilical cord blood lactate levels as an indicator of intrapartum asphyxia in caesarean sections done for fetal distress at term. Material & Methods: It was a prospective study conducted on 150 women undergoing caesarean section for fetal distress and non fetal distress indications. The participants were categorized into 3 groups of 50 women each. Group 1 included women with fetal heart rate abnormalities. Group 2 included women with meconium stained liquor and group 3 which served as control included women who had elective caesarean section. Neonatal cord blood lactate, cord blood pH and perinatal outcome were studied in all the 150 women. Statistical analysis was done by ANOVA, Tukey and Tamhane's T2 test. Results: Significantly higher cord blood lactate values (P value <0.001) and lower pH values (P value<0.05) were noted among the neonates with both the intrapartum signs of distress as compared to controls. Cord blood lactic acidosis was present in 86% neonates of group 1, 42% neonates of group 2 and 2% neonates of group 3 while significant low pH was noted in 28% neonates of group 1, 22% neonates of group 2 and none of the neonates of group 3. The positive predictive value of cord blood lactic acidosis for intrapartum asphyxia was14% in group 1 and 47.6% in group 2 while the positive predictive value of cord blood pH in group 1 and 2 was30.7% and 90% respectively. Lactic acidosis had 100% negative predictive value in both the groups while pH had negative predictive value of 94.4% and 97.4% in group 1 and 2 respectively. Conclusion: Fetal lactic acidosis is a reliable and accurate indicator of foetal hypoxia hence could supplement the diagnosis of genuine fetal distress but it is a poor predictor of adverse neonatal outcome.