The value of Doppler determination of the maximum systolic blood flow velocity in the middle cerebral artery in the diagnosis of fetal anemia due to Rh-incompatibility in pregnancy

Timely and accurate diagnosis of fetal anemia due to immune incompatibility during pregnancy is of great importance in choosing the most rational tactics of pregnancy management, treatment options, and delivery methods and time. To successfully solve this problem, Doppler data are currently used to determine the maximum systolic blood flow velocity in the middle cerebral artery, which is measured using the tables specially drawn up by G. Mari et al. for this purpose. Similar tables using the same procedure were made by the authors (V.N. Demidov et al.). However, the authors’ studies have shown that the procedures used by foreign authors to calculate the blood flow velocity significantly overestimate its values in fetuses with moderate fetal hemolytic disease, unjustifiably transferring them to a severe patient group. This eventually leads either to a more frequent unjustified delivery or to unjustified cordocentesis. Instead of determining the maximum systolic blood flow velocity in the middle cerebral artery, the foreign authors presently propose to calculate an indicator, such as MoM, that is the quotient of the individual blood flow velocity by its average statistical value for each gestational age. However, from the author’s point of view, the certain disadvantage of this method is that the practitioner usually does not know what this indicator is, and acts, without understanding the essence of the phenomenon being studied. Moreover, MoM does not improve diagnostic accuracy at all, because it fully reflects the same process as blood flow velocity. The advantages of determining the blood flow velocity should include the fact that these indicators are generally accepted and allow a much better study of the essence of the phenomenon under study and especially the time course of its change, which is of great importance in choosing the optimal time of delivery.

Rh-incompatibility in pregnancy, Doppler ultrasound, assessment of the information content of MoM and maximum systolic blood flow velocity