Trans-abdominal monitoring of fetal arterial oxygen saturation using pulse oximetry

A trans-abdominal fetal pulse oximeter is described for the determination of arterial oxygen saturation in the fetal brain. The system uses continuous wave near-infrared spectroscopy to measure the absorption of light, as it passes through the fetal head, at three different wavelengths. The absorption corresponds to changes in oxy-hemoglobin and deoxy-hemoglobin concentrations, which can be used to determine the oxygenation state of a given tissue. Experimental results on the forearm, phantom models and other two layer blood models demonstrate the feasibility of this technique