ASSOCIATION OF ABNORMAL FLOW VELOCITY WAVE-FORMS IN THE UTERINE ARTERY WITH FREQUENCY-SPECIFIC FETAL HEART-RATE-VARIABILITY

The aim of the study was to determine if abnormal flow velocity wavefo rms in the uterine artery are associated with altered frequency-specif ic fetal heart rate variability (HRV). Fetuses in the last third of ge station were studied. In seven fetuses the pulsatility index (PI) of t he blood flow velocity waveform in the uterine artery was increased (G roup II), and in ten fetuses the PI was normal (Group I). Frequency-sp ecific HRV (0.025-0.07 Hz, 0.07-0.13 Hz, 0.13-1.0 Hz) was quantified b y power spectral analysis and correlated with the PI in the uterine ar tery, umbilical artery and the middle cerebral artery. The slow variab ility dominated the fetal HRV. There was no difference between the gro ups in the mean frequency-specific variability. In Group II, an increa se of the PI in the umbilical artery and a decrease in the middle cere bral artery correlated with an increase of HRV, the increase being gre atest at the lowest frequency band.