Noninvasive diagnosis by Doppler ultrasonography of fetal anemia due to maternal red-cell alloimmunization. Collaborative Group for Doppler Assessment of the Blood Velocity in Anemic Fetuses.
BACKGROUND
Invasive techniques such as amniocentesis and cordocentesis are used for diagnosis and treatment in fetuses at risk for anemia due to maternal red-cell alloimmunization. The purpose of our study was to determine the value of noninvasive measurements of the velocity of blood flow in the fetal middle cerebral artery for the diagnosis of fetal anemia.


METHODS
We measured the hemoglobin concentration in blood obtained by cordocentesis and also the peak velocity of systolic blood flow in the middle cerebral artery in 111 fetuses at risk for anemia due to maternal red-cell alloimmunization. Peak systolic velocity was measured by Doppler velocimetry. To identify the fetuses with anemia, the hemoglobin values of those at risk were compared with the values in 265 normal fetuses.


RESULTS
Fetal hemoglobin concentrations increased with increasing gestational age in the 265 normal fetuses. Among the 111 fetuses at risk for anemia, 41 fetuses did not have anemia; 35 had mild anemia; 4 had moderate anemia; and 31, including 12 with hydrops, had severe anemia. The sensitivity of an increased peak velocity of systolic blood flow in the middle cerebral artery for the prediction of moderate or severe anemia was 100 percent either in the presence or in the absence of hydrops (95 percent confidence interval, 86 to 100 percent for the 23 fetuses without hydrops), with a false positive rate of 12 percent.


CONCLUSIONS
In fetuses without hydrops that are at risk because of maternal red-cell alloimmunization, moderate and severe anemia can be detected noninvasively by Doppler ultrasonography on the basis of an increase in the peak velocity of systolic blood flow in the middle cerebral artery.
Mari
G
G
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Conn 06520-8063, USA. giancarlo.mari@yale.edu
Deter
R L
RL
Carpenter
R L
RL
Rahman
F
F
Zimmerman
R
R
Moise
K J
KJ
Dorman
K F
KF
Ludomirsky
A
A
Gonzalez
R
R
Gomez
R
R
Oz
U
U
Detti
L
L
Copel
J A
JA
Bahado-Singh
R
R
Berry
S
S
Martinez-Poyer
J
J
Blackwell
S C
SC
D001783:Blood Flow Velocity; D001787:Blood Group Incompatibility / Q000150:complications; D017218:Cordocentesis; D004899:Erythroblastosis, Fetal / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005865:Gestational Age; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D007518:Isoantibodies / Q000097:blood; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic; D011446:Prospective Studies; D012372:ROC Curve; D012016:Reference Values; D012203:Rh Isoimmunization; D012680:Sensitivity and Specificity; D018617:Ultrasonography, Doppler, Pulsed; D016216:Ultrasonography, Prenatal
D006454:Hemoglobins; D007518:Isoantibodies