[Doppler sonography in obstetric diagnosis: I: General physical and clinical principles]

The paper gives an overview of the application in obstetrics of Doppler-ultrasound for blood flow measurements. Both usual methods, the continuous-wave and the pulsed Doppler are compared, including the safety aspects of the investigation. The advantages and disadvantages of quantitative and qualitative analysis of the Doppler spectrum are discussed and the necessary terms as Pulse Repetition Frequency (PRF), High Pass Filter (HPF), sample volume, aliasing and Doppler spectrum explained. The vessels of interest and the clinical importance they reflect are demonstrated. The importance of this new non-invasive mean in the assessment of utero-feto-placental haemodynamics is underlined.