[Possibilities for error in the pulsed Doppler method for measuring blood flow in the fetus]

Fetal blood flow volume was measured non-invasively by means of a pulsed Doppler instrument in 35 patients between the 30th and 41st week of gestation. In the descending fetal aorta the mean blood flow volume was 230 +/- 44 ml/min/kg, in the umbilical vein 121 +/- 27 ml/min/kg. The relatively large range of the individual variations from the mean value (up to almost 20%) was due to 1/2 to the determination of the vessel diameter and to 1/2 to the Doppler measurement itself. The investigations performed show that the Doppler technique permits a rough quantitative statement about fetal blood flow volume. However, the relative large range of variation does not allow a clinical assessment, to date.