Comparison of different blood flow parameters for evaluating blood flow spectra in fetal growth retardation

: Uteroplacental and foetoplacental vascular resistance is generally high in pregnancies complicated by intrauterine growth retardation. Assessment of flow velocity curves using angle-independent indices as A/B ratio, resistance index (RI) or pulsatility index (PI) cannot classify all cases with pathological flow velocity profiles. Beneath the pulsatility the maximum frequency outline of the flow velocity waveform offers additional clinical information. The evaluation of flow velocity curves using polynome analysis (including III degrees) provides additional data including occurrence of diastolic notching and can be used as a more sensitive indicator of impaired uteroplacental blood flow. In such pregnancies accurate evaluation of the maximum flow velocity outline with polynome analysis has been shown to be an important qualitative criterion in the assessment of blood flow velocity waveforms.