Near infrared spectroscopy applied to intrapartum fetal monitoring.

NIRS as a technique for intrapartum fetal monitoring is at present only able to be used as an investigative research tool. We feel that it has enormous potential to give access to previously inaccessible information about fetal cerebral haemodynamic and oxygenation changes in labour. The major limitations at present are technological, and the problems addressed in this review need to be resolved before clinicians can advance the technique. In the future, standardized measurement parameters that truly reflect cerebral oxygenation, along with a range of normality need to be established. This would require the study of very large numbers of uncomplicated labours. Comparison with data from labours complicated by what we currently call 'fetal distress' and correlation with outcome measures in the neonate would then be needed to determine abnormal patterns of change related to intracerebral hypoxia-ischaemia. This is severely limited by the current inability to measure absolute levels of oxygenation necessary to validate the method. To use the technique for routine surveillance in labour would require considerable refinement of both the equipment and the data analysis systems to improve the acceptability of the technique. It is not possible to envisage a role for NIRS in routine surveillance of low-risk pregnancies, but it may in future prove to have a role in the management of high-risk pregnancies and may well improve our understanding of intracerebral pathology.