ABSTRACT
The objective of this study was to evaluate the effect of fetal blood sampling on
atrioventricular blood flow velocity waveforms. Flow velocity waveforms were measured
from mitral and tricuspid valve immediately before and after fetal blood sampling
in 25 normally grown and 10 growth-retarded fetuses. This latter group was characterized
by abnormal Doppler indices in umbilical artery and middle cerebral artery suggestive
of uteroplacental insufficiency as the causative factor of the impaired growth. The
flow velocity parameters studied were peak velocity during early and active ventricular
filling, time velocity integral, and fetal heart rate. Different indices were then
calculated as expressions of ventricular diastolic function and cardiac output. In
normally grown fetuses, both peak velocity during early diastole and time velocity
integral values significantly increased after fetal blood sampling from both atrioventricular
valves, whereas no significant changes were evidenced in the other parameters considered.
Gestational age at the time of the procedure was positively related to the amplitude
of these changes. In growth-retarded fetuses, fetal blood sampling induced a significant
decrease in time velocity integral value from tricuspid valve, suggestive of a fall
in right ventricle output. The amplitude of the decrease was significantly related
to the severity of acidosis in umbilical vein. In conclusion, the cardiac hemodynamic
response to fetal blood sampling differs between normally grown and growth-retarded
fetuses. This difference may explain the higher rate of complications occurring in
the latter group of fetuses after blood sampling.
Keywords
Fetal blood sampling - Doppler ultrasonography - fetal echocardiography - intrauterine
growth retardation - fetal blood - prenatal diagnosis
