Predicting the severity of fetal anemia using time-domain measurement of volume flow in the fetal aorta.
OBJECTIVE
To assess the value of fetal aortic time-domain measurement of volume flow (using color velocity imaging quantification (CVI-Q)) in predicting the severity of fetal anemia.


METHODS
This was a prospective observational study, in which 24 pregnant women with suspected fetal anemia due to rising anti-red blood cell antibody titers underwent cordocentesis. The fetal aortic time-domain volume flow was measured before fetal blood sampling for fetal hemoglobin investigation. We examined the correlation between increased fetal aortic time-domain volume flow (>2 SD for gestational age) and fetal anemia (hemoglobin level <2 SD for gestational age).


RESULTS
Seventeen fetuses had anemia, and seven had normal hemoglobin. There was a strong correlation between the increase in fetal aortic time-domain volume flow and the drop in hemoglobin value (r = 0.81; P < 0.01). The sensitivity of this technique to predict fetal anemia was 81.3% and the specificity was 71.4%. The mean increase over time in aortic CVI-Q in anemic fetuses was 323.2 mL/min (95% CI, 200.1 to 446.4) compared with 86.9 mL/min (95% CI, -17.7 to 191.5) in the non-anemic group (P = 0.004).


CONCLUSIONS
Fetal aortic time-domain measurement of volume flow is significantly increased in cases of fetal anemia due to red-cell alloimmunization. These findings can be used to improve the sensitivity, specificity and positive predictive value of the non-invasive techniques used to predict fetal anemia, and may help in the selection of pregnancies that require cordocentesis and transfusion.
Harrington
K
K
Homerton University Hospital and Barts and the London School of Medicine, London, UK. kevin.harrington@virgin.net
Fayyad
A
A
Nicolaides
K H
KH
D000740:Anemia / Q000097:blood / Q000000981:diagnostic imaging*; D001011:Aorta / Q000000981:diagnostic imaging* / Q000196:embryology; D004899:Erythroblastosis, Fetal / Q000097:blood / Q000000981:diagnostic imaging*; D005260:Female; D005315:Fetal Diseases / Q000097:blood / Q000000981:diagnostic imaging; D005865:Gestational Age; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D012039:Regional Blood Flow; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color; D016216:Ultrasonography, Prenatal
D006454:Hemoglobins