[Noninvasive diagnosis of fetal anemia in Rh-alloimmunized pregnancies by color Doppler].
INTRODUCTION Fetal anemia is usually diagnosed by invasive procedures, such as amniocentesis and cordocentesis. As these procedures carry a substantial risk for pregnancy loss, a nonivasive method for diagnosing fetal anemia is needed. Doppler allows measurement of blood flow velocity in fetal vessels. In anemic fetuses increased velocities in medial cerebral artery (MCA) are registered. The aim of our study was to evaluate if there were changes in blood flow waveforms in anemic fetuses' MCA, and if these changes correlated with values of fetal hematological parameters.


METHODS
A clinical study evaluated 172 pregnancies of gestational age between 28 and 32 weeks, in which cordocentesis was performed due to maternal Rh-alloimmunization. During sonographic examination we evaluated blood flow velocities and pulsatility index (Pi) in MCA. We registered hematological parameters such as hemoglobin and hematocrit. Based on hemoglobin levels, all fetuses were divided into four groups: nonanemic (140 g/l); mild anemia (120-139.9 g/l); moderate anemia (100-119.9 g/l) and severe anemia requiring intrauterine transfusion (99.9 g/l). We compared mean systolic velocities and Pi between groups and studied the correlation between MCA mean systolic velocities and hemoglobin and hematocrit values. Statistical analysis was done using ANOVA test and parameter linear correlation. The difference was considered to be significant if p < 0. 05.


RESULTS
Out of 172 fetuses, 60 (34.09%) were nonanemic, 56 (31.82%) showed mild anemia, 56 (31.82%) moderate anemia and 24 (13.64%) fetuses had severe anemia. Anemic fetuses had significantly higher MCA flow velocities compared to nonanemic fetuses. Values of Pi decreased in severe forms of fetal anemia, but the difference wasn't significant. Levels of hemoglobin and hematocrit showed inverse correlation with the values of MCA mean systolic velocities, while correlation with the values of Pi wasn't observed.


CONCLUSIONS
Cerebral blood flow velocity in medial cerebral artery was assessed to diagnose fetal anemia. MCA mean systolic velocity is increased in anemic fetuses and correlates with the degree of anemia. The main advantage of this parameter is that advanced software programs are not necessary. We can conclude that in cases of Rh-alloimmunization in anemic fetuses increased MCA mean systolic velocities are registered. There is an inverse correlation between MCA mean systolic velocities and hemoglobin and hematocrit values. We suggest that measurements of MCA mean systolic velocities should be used in fetuses at risk for anemia and in selection of fetuses requiring invasive procedures.
Mandic
Vesna
V
Ginekolosko-akuserska klinika "Narodni front", Beograd.
Mikovic
Zeljko
Z
Filimonović
Dejan
D
Dukić
Milan
M
Vasiljević
Mladenko
M
Bogavac
Mirjana
M
D000740:Anemia / Q000000981:diagnostic imaging*; D001783:Blood Flow Velocity; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D011247:Pregnancy; D012203:Rh Isoimmunization / Q000150:complications*; D018615:Ultrasonography, Doppler, Color; D016216:Ultrasonography, Prenatal