Verifying fetal scalp lactate testing results as measured by a portable lactate analyzer

Aim. To determine the reference values of lactate concentration in the blood obtained from the fetal presenting part and measured by a portable lactate analyzer. Materials and methods. A prospective study included 92 pregnant women at delivery who underwent fetal scalp blood sampling to determine the lactate level and umbilical artery sampling to assess the acid-base balance. Results. An increase in scalp lactate concentration was associated with an increase in umbilical artery pCO2, base deficit, and a decrease in blood pH. Lactate concentration >4.9 mmol/l was associated with a higher rate of an emergency delivery. However, the fetal condition was over-diagnosed in 74.5% of cases. Increasing the cutoff threshold of scalp lactate to 5.9 mmol/L allows a 22.8% reduction in unwarranted surgical delivery. Conclusion. Normal and pre-acidosis fetal scalp lactate concentrations measured by the portable lactate analyzer (Lactate Scout) were 44.8 and 4.9-5.8 mmol/L, respectively. Fetal scalp lactate concentration >5.9 mmol/L was associated with a high risk of acidosis requiring emergency delivery.

fetal hypoxia, scalp lactate, cardiotocography (CTG), cord blood gases, blood acid-base balance (ABB), acidosis