Fetal pulse oximetry: a critical appraisal

Despite 40 years of cumulative clinical experience, and a number of randomized clinical trials, electronic fetal heart rate monitoring is perceived by many obstetrical caregivers as a suboptimal method of intrapartum fetal assessment. Fetal pulse oximetry emerged 15 years ago as a promising new technology intended to improve assessment of fetal condition during labor. A large amount of physiologic data and one large randomized clinical trial have brought this technology into clinical practice. We know that fetal acidemia is rare when the arterial oxygen saturation is >30% but fetal pulse oximetry as currently understood and applied does not reduce the overall cesarean rate. Thus, many clinicians remain unconvinced of the benefit of this technology and its utilization has stalled in the US and Europe. We need to further understand if there is a way to use fetal pulse oximetry in the setting of labor dystocia and a non-reassuring fetal heart rate pattern. Although hypoxemia is an accepted mechanism of fetal brain injury, other potential mechanisms should be explored. Current controversies and fertile areas of research are presented.