[Usefulness of Doppler ultrasonography to detect fetal anemia in rh alloimmunized pregnancies].
BACKGROUND
pregnant women with Rh alloimmunization (RhA) are submitted to invasive procedures to assess fetal anemia (FA). Recently a non-invasive approach to FA diagnosis has been proposed using Doppler ultrasound (DU) to identify increased peak velocity of systolic blood flow (Vm) in the middle cerebral artery (MCA).


METHODS
eleven Rh alloimmunized pregnant women with serum red-cell antibody titers > 1:16 were included. Twenty-four procedures were done measuring the VmMCA followed by cordocentesis and fetal hemoglobin (FH) analysis. Pearson's linear correlation was calculated between the multiples of the median (MoM) of the VmMCA and the MoM of the FH, as well as the sensitivity, specificity and positive predictive value (PPV) for FA prediction.


RESULTS
we found FA (FH mean = 6 g/dL) in 12 of 24 evaluations with a VmMCA mean of 1.5 MoM and a range from 1.22 to 1.68 MoM; in the remaining 12 cases the FH was normal (FH mean = 13.1 g/dL) with a VmMCA mean of 0.97 MoM and a range from 0.35-1.17 MoM (p < 0.001). Eleven fetuses with anemia had a MoM of the VmMCA above 1.29, except one with 1.22 MoM. The linear correlation between the MoM of the VmMCA and the MoM of FH was 0.83. The sensitivity of the MoM of the VmMCA to detect FA was 91%, specificity of 100% and PPV of 100%.


CONCLUSIONS
DU measurement of the VmMCA was a useful non-invasive technique to evaluate FA. The sensitivity and PPV for FA diagnosis in RhA was above 90%.
Ochoa-Torres
Mauro Alberto
MA
Departamento de Medicina Fetal, Hospital Regional de Especialidades 23, Instituto Mexicano del Seguro Social, Monterrey, Nuevo León, Mexico.
Hernández-Herrera
Ricardo Jorge
RJ
Luna-García
Sergio Arturo
SA
Forsbach-Sánchez
Gerardo
G
D000740:Anemia / Q000097:blood* / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000097:blood* / Q000000981:diagnostic imaging*; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D012203:Rh Isoimmunization; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal