Objectives: (1) To investigate fetal intracranial circulation, relative to peripheral blood flow, during labor with abnormal cardiotocographic (CTG) patterns, using three non-invasive methods. (2) To determine the utility of monitoring middle cerebral artery (MCA) Doppler during labor.
Interventions: Fetuses were assessed using simultaneous CTG, pulse oximetry, and Doppler ultrasonography of both the MCA and umbilical artery (UA) to measure the pulsatility index (PI), resistance index (RI), and flow velocity integral (FVI).
Study design: During labor 20 term fetuses with abnormal CTG patterns and oxygen saturation values >30%, and 24 term fetuses with abnormal CTG patterns and oxygen saturation values <30% were studied, and peripartum outcomes were compared. The groups were comparable with regard to maternal age and parity. Results were evaluated using the Student's t-test and Fisher exact test.
Results: MCA Doppler showed significantly lower PI and RI, and higher FVI in the presence of reduced oxygen saturation. Differences in fetal outcomes between the two groups correlated with MCA Doppler findings.
Conclusions: In experienced hands, Doppler screening of fetal middle cerebral artery waveforms during labor can be useful in the evaluation of intrapartum hypoxia in complicated pregnancies.