Fetal pulse oximetry and non-reassuring heart rate

The aim of the study is to assess the continuous monitoring of fetal blood oxygen saturation (SpO2) during labour using a fetal pulse oximeter in cases of abnormal fetal heart rate (FHR). To determine whether pulse oximetry has the potential to replace scalp blood pH sampling in infants with abnormal heart rate tracings, the correlation between the Hammacher score and SpO2 during labour, scalp pH and arterial cord pH was evaluated. 34 fetal blood samples (FBS) were evaluated in cases of suspicious, pre-pathological or pathological heart rates. Using the FS-14 prototype, 24 fetal blood samples (FBS) were measured in cases of suspicious FHR with an average SpO2 of 42.3% and pH of 7.28, nine in cases of pre-pathological FHR with an average SpO2 of 34.1% and pH of 7.25 and one pathological FHR with an average SpO2 of 24% and pH of 7.162. In those cases where SpO2 was > 40% during labour, no neonate was observed to suffer on hypoxaemia or acidosis and no arterial cord pH was below 7.20. For the future we have the need of collecting more data to support the use of pulse oximetry as a replacement for fetal blood sampling or as a basis for deciding on operative intervention.