The effect of maternal oxygen administration on fetal pulse oximetry during labor in fetuses with nonreassuring fetal heart rate patterns

Objective Using fetal pulse oximetry, we sought to quantify the impact of maternal oxygen administration in the management of nonreassuring fetal heart rate patterns. Study design In fetuses with specified abnormal nonreassuring fetal heart rate patterns, oxygen was administered to the mother, and fetal oxygenation was monitored with fetal pulse oximetry. After the fetal oxygen saturation on room air was recorded as a baseline, oxygen was administered to the mother for 30 minutes at 40% fraction of inspired oxygen and then 30 minutes at 100% of inspired oxygen. The average fetal oxygen saturation during the last 15 minutes of each period was calculated. Paired Student t test was used for comparison to baseline values. Results Compared with baseline values, a significant increase in fetal oxygen saturation was identified in women who received oxygen at 40% fraction of inspired oxygen (mean increase, 4.9%; P = .001) and at 100% of inspired oxygen (mean increase, 6.5%; P = .003). Conclusion The administration of supplemental oxygen to laboring patients with nonreassuring fetal heart rate patterns increases fetal oxygen saturation substantially and significantly. Fetuses with the lowest initial oxygen saturations appear to increase the most.