Fetal pulse oximetry: the European experience

Pulse oximetry is a technique of fetal monitoring during labour based on non-invasive measurement of fetal arterial oxygen saturation. It has been shown in animal studies that metabolic acidosis occurred for a fetal arterial oxygen saturation below 30%. One of the main debates during initial experience in humans, was focused on the adequate cut-off for intervention (or non-intervention), and the duration of time below this threshold. Most of the data feeding this debate came from Europe where it was generally felt that determining an adequate cut-off was a prerequisite to the design of randomised trials.