Doppler ultrasonographic evidence of intrapartum brain-sparing effect in fetuses with low oxygen saturation according to pulse oximetry

OBJECTIVE: This study was undertaken to verify by means of Doppler ultrason ography and simultaneous fetal pulse oximetry the redistribution of fetal b lood flow in favor of the brain during intrapartum hypoxemia. STUDY DESIGN: During labor 11 term fetuses with abnormal heart rate pattern s and arterial oxygen saturation <30% and 14 control term fetuses with norm al oxygen saturation were simultaneously monitored by pulse oximetry and Do ppler ultrasonography. The results were compared with the Student t test. RESULTS: The blood flow velocity in the middle cerebral artery was signific antly higher in the presence of reduced oxygen saturation, implying lower p ulsatility and resistance indices (P < .001). The reduction of blood flow i n the umbilical artery was not significant (P = .61). CONCLUSION: Simultaneous intrapartum pulse oximetry and Doppler ultrasonogr aphy proved that reduced arterial oxygen saturation (<30%) is associated wi th profound changes in fetal hemodynamics and could be tolerated for only a limited period, which should be the subject of further studies.