Intrapartum fetal surveillance: Monitoring fetal oxygenation with fetal blood sampling and umbilical cord blood analysis

Although electronic fetal heart rate monitoring remains the most popular technique for fetal surveillance during labour, there is much concern about the ever rising Caesarean section rate, probably partly due to this practice. Fetal blood sampling is still the gold standard when it comes to measuring fetal oxygenation. There is enough evidence that the combination of EFM and FBS is more efficient in detecting fetal hypoxia and prevents an unnecessary high intervention rate. Another tool to assess the efficacy of intrapartum fetal monitoring is the measurement of pH and blood gases in the umbilical cord blood. This method can also rule out fetal hypoxia in cases with unreassuring fetal heart rate patterns, meconium and low Apgar scores. Continuing inadequate fetal oxygenation during labour may lead to pathological fetal acidaemia. This means that there is a mixed acidosis in the fetal blood with hypercarbia and a substantial base deficit. A pH <7.00 may lead to later sequelae but the base deficit, indicating the duration of the insult, is a better predictor of neonatal morbidity.