Point-of-care umbilical arterial lactate and newborn outcomes in a low resource setting: cohort study

Birth asphyxia contributes substantially to the burden of intrapartum stillbirth and neonatal mortality in resource limited countries. We investigated clinical correlates and neonatal outcomes of lactate analysis of umbilical arterial cord blood in a large referral maternity unit in Malawi using a point-of-care test (Lactate Xpress, Nova Biomedical, Runcorn, UK) and examined maternal and neonatal characteristics and outcomes.

There were 389 live births and 12 intrapartum stillbirths during the study. The median umbilical arterial lactate concentration was 3.4 mmol/L (interquartile range 2.6-4.9). Umbilical arterial lactate concentrations among the 45 babies admitted for special neonatal care were above 5 mmol/L in 16/45 (36%) of cases, with no fatality below 13 mmol/L. A positive malaria rapid diagnostic test was associated with hyperlactatemia (p < 0.05). In receiver-operator characteristic (ROC) analysis using a lactate cutoff of 5 mmol/L, areas under the curve were 0.72 (95% CI 0.66-0.79) and 0.64 (95% CI 0.58-0.69) for the Apgar score at 1 and 5 min respectively. This approach can identify safely those newborns that are unlikely to require additional monitoring. Scale-up implementation research in low resource country referral units is needed. The influence of malaria on neonatal hyperlactatemia requires further exploration.