Noninvasive diagnosis by Doppler ultrasonography of fetal anemia resulting from parvovirus infection

OBJECTIVE: The purpose of this study was to evaluate the feasibility of the middle cerebral artery peak systolic velocity for the detection of fetal anemia in pregnancies that are complicated by parvovirus B19 infection. STUDY DESIGN: Doppler measurements of the middle cerebral artery peak systolic velocity were performed weekly in 32 fetuses at risk for anemia because of maternal parvovirus infection documented by the presence of serum immunoglobulin M antibody. The values of the middle cerebral artery peak systolic velocity and hemoglobin were expressed as multiples of the median. These values were plotted on reference ranges that had been established previously. A cordocentesis was performed either because of fetal ascites or when the middle cerebral artery peak systolic velocity values suggested anemia (middle cerebral artery peak systolic velocity, >1.50 multiples of the median). RESULTS: Gestational age at study entry ranged from 15.1 to 37 weeks. There were 17 fetuses with middle cerebral artery peak systolic velocity of >1.50 MoM (group 1). Sixteen cordocenteses were performed in these fetuses. All 16 fetuses were anemic (15 severely and 1 mildly). Thirteen fetuses had signs of hydrops (12 with severe and 1 with mild anemia). Group 2 included 15 fetuses with the middle cerebral artery peak systolic velocity values <1.50 MoM. Two cordocenteses were performed. One fetus was mildly anemic; the second fetus was not anemic. The remaining 13 fetuses of this group did not have any complications and were not anemic at birth. The sensitivity of the middle cerebral artery peak systolic velocity (>1.50 MoM) for the prediction of anemia because of parvovirus infection was 94.1%; the specificity was 93.3 %; the positive and negative predictive values were 94.1% and 93.3%, respectively. CONCLUSION: Fetal anemia caused by parvovirus infection 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.     

Variables that affect the middle cerebral artery peak systolic velocity in fetuses with anemia and intrauterine growth restriction

We have previously reported that the fetal middle cerebral artery (MCA) peak systolic velocity (PSV) increases in anemic fetuses and in fetuses with intrauterine growth restriction (IUGR). We hypothesized that the pathophysiology for the increased MCA PSV is different in anemic and IUGR fetuses. Thus the aim of this study was to determine the factor(s) among fetal umbilical vein blood pH, Po2, Pco2, and hemoglobin that might affect the MCA PSV in fetuses with anemia and IUGR. This study included two groups of fetuses. The first group included fetuses at risk for anemia because of red cell alloimmunization, whereas the second group included IUGR fetuses. For both groups of fetuses, we determined hemoglobin, umbilical vein blood gases -- at cordocentesis in anemic fetuses and immediately after cesarean delivery in IUGR fetuses -- and MCA PSV before cordocentesis, or before delivery. The relationship between MCA PSV and the hemoglobin, Po2, Pco2, and pH values for the anemic and the IUGR fetuses were assessed by regression analysis using multiples of the mean. There were 14 fetuses in the first group and 22 fetuses in the second group. In the first group, the only parameter that was related to MCA PSV was the fetal hemoglobin (R2 = 0.34; p < 0.05); in fetuses with IUGR, the Pco2 (R2 = 0.36; p < 0.01) and the PO2 (R2 = 0.30; p < 0.01) correlated well with the MCA PSV, whereas no relationship was found between the MCA PSV and the hemoglobin. The data indicate that the mechanism of high MCA PSV is different in anemic and nonanemic IUGR fetuses, and suggest that the process of cerebral autoregulation is present in the preterm IUGR fetus.     

The value of middle cerebral artery peak systolic velocity in the diagnosis of fetal anemia after intrauterine death of one monochorionic twin

OBJECTIVE: The purpose of this study was to assess the value of the fetal middle cerebral artery peak systolic velocity in the prediction of anemia within 24 hours of the death of one monochorionic twin in twin-to-twin-transfusion syndrome and to establish the correlation between middle cerebral artery peak systolic velocity and hemoglobin concentration in fetuses who are at risk for acute anemia. STUDY DESIGN: Doppler examination of the middle cerebral artery peak systolic velocity was performed in 20 monochorionic survivors of pregnancies that were complicated by twin-to-twin-transfusion syndrome that occurred between 20 and 34 weeks of gestation. Doppler examination was performed before cordocentesis and after intrauterine transfusion when appropriate. Both hemoglobin concentration and middle cerebral artery peak systolic velocity were expressed in multiples of the median. Severe anemia was defined as hemoglobin concentration of <0.55 multiples of the median, and we used the cutoff point of 1.50 times the median values at any gestational age to calculate the sensitivity and specificity of middle cerebral artery peak systolic velocity in detecting moderate or severe anemia. RESULTS: Fetal anemia was confirmed in 10 of 20 fetuses. We performed seven intrauterine transfusions. The sensitivity and specificity of middle cerebral artery peak systolic velocity in the prediction of severe fetal anemia were of 90%, with a false-negative rate of 10%. The correlation between peak systolic velocity and hemoglobin concentration both before and after transfusion was evaluated by regression analysis and was strongly significant. CONCLUSION: In fetuses who are at risk of acute anemia, the measurement of middle cerebral artery peak systolic velocity was found to be a reliable noninvasive diagnostic tool and may be helpful in counseling and planning invasive assessment.     

Correction of fetal anemia on the middle cerebral artery peak systolic velocity

OBJECTIVE: To assess the effect of correction of fetal anemia on the middle cerebral artery peak systolic velocity values. METHODS: With Doppler ultrasonography, middle cerebral artery peak systolic velocity was measured in 41 fetuses before and immediately after 54 intrauterine transfusions for severe red blood cell alloimmunization. The fetuses were divided into two groups: 17 fetuses studied at first transfusion (group A), and 24 fetuses enrolled to the study after the first transfusion (group B). Both fetal hemoglobin and middle cerebral artery peak systolic velocity were plotted over the respective reference ranges as a function of gestational age. Both values were expressed as multiples of the median and analyzed with paired t test. RESULTS: The values of middle cerebral artery peak systolic velocity decreased in all but one fetus of group B (P <.05). The values of middle cerebral artery peak systolic velocity before transfusion were above the upper limit of the reference range in 60% of the fetuses of group A and in 38% of group B, respectively. After correction of anemia, only one value remained above the upper limit of the reference range. CONCLUSION: The correction of fetal anemia with intrauterine blood transfusion decreases significantly and normalizes the value of the fetal middle cerebral artery peak systolic velocity.     

Doppler ultrasound velocimetry for timing the second intrauterine transfusion in fetuses with anemia from red cell alloimmunization.

OBJECTIVE: Middle cerebral artery peak systolic velocity has been successfully used for timing the first cordocentesis in fetuses who are at risk for anemia because of maternal red cell alloimmunization. The effects on Doppler velocimetry after the intrauterine transfusion of adult blood to these fetuses are unknown. The objective of this study was to assess the applicability of Doppler methods for the prediction of severe anemia in fetuses who had undergone 1 previous intrauterine transfusion. STUDY DESIGN: Doppler examination of middle cerebral artery peak systolic velocity was performed before cordocentesis in 64 fetuses who had undergone 1 previous intrauterine transfusion. Timing of the second intrauterine transfusion was based on traditional criteria. Anemia was defined as mild (hemoglobin value between 0.84 and 0.65 multiples of the median), moderate (hemoglobin value <0.65-0.55 multiples of the median), and severe (hemoglobin value <0.55 multiples of the median). Receiver operator characteristic curves were created to select threshold values to identify the 3 degrees of anemia with a sensitivity of 100%. RESULTS: Gestational age at the Doppler study ranged from 19 to 36 weeks. Forty-six fetuses (72%) were not or mildly anemic; 7 fetuses (11%) were moderately anemic, and 11 fetuses (17%) were severely anemic. Middle cerebral artery peak systolic velocity for the prediction of severe, moderate, and mild anemia at a sensitivity of 100% showed false-positive rates of 6%, 37%, and 70%, respectively. CONCLUSION: In fetuses who have undergone 1 previous intrauterine transfusion because of maternal red cell alloimmunization, timing the second intrauterine transfusion can be determined noninvasively by Doppler ultrasonography on the basis of an increase in the peak velocity of systolic blood flow in the middle cerebral artery.     

Prediction of fetal anemia by middle cerebral artery Doppler

ObjectivesTo assess the value of peak systolic velocity in the middle cerebral artery (MCA) in prediction of fetal anemia as a non invasive method in non hydropic fetuses.MethodsThe study included 30 pregnant women with non hydropic fetuses and with known red cell antibodies. Full ultrasound examination was done and peak velocity of systolic cerebral blood flow in MCA was measured. If severe anemia was suspected, fetal blood sampling by cordocentesis was performed.ResultsThirty fetuses were examined, 22 were anemic and eight had a hemoglobin value within a normal range. The mean MCA peak systolic velocity for fetus with the normal hemoglobin (Hb) was 48.98 ± 13.94 while that for the anemic fetus was 64.79 ± 11.97 and P = 0.004.Sensitivity of increased peak velocity of systolic blood flow in MCA for prediction of fetal anemia was 90.5% and specificity was 78.6%.ConclusionDoppler of peak velocity of systolic blood flow in MCA can be reliable in predicting anemia so delaying invasive methods until treatment (blood transfusion) is expected to be necessary.     

Splenic artery Doppler peak systolic velocity predicts severe fetal anemia in rhesus disease

OBJECTIVE: We sought to determine whether main splenic artery Doppler peak systolic velocity predicts severe anemia in the rhesus-alloimmunized fetus.Study Design: Splenic artery Doppler peak systolic velocity was obtained before cordocentesis in rhesus-alloimmunized fetuses. Normative values for mean peak systolic velocity based on gestational age were obtained cross-sectionally from a separate group of 144 normal fetuses. The peak systolic velocity values in the study group were expressed as multiples of the median for gestation, and threshold values were used as a screening test for severe anemia. The hemoglobin deficit was defined as mean hemoglobin for gestation minus measured hemoglobin. A hemoglobin deficit value of > or =5 g/dL was used to define severe anemia. We used the peak systolic velocity to screen for severe anemia in the overall study group and the subgroups with or without prior transfusions. RESULTS: The study population consisted of 26 singleton nonhydropic fetuses in which cordocentesis and Doppler measurements were performed on a total of 55 occasions. The mean gestational age and standard deviation at cordocentesis was 29.6 +/- 4.0 weeks. Severe anemia was noted in 20% of fetal cord blood specimens obtained. On the basis of a receiver operating characteristic curve, a peak systolic velocity of > or =1.4 multiples of the median had a detection rate of 100%, with a false-positive rate of 20.8% in the subgroup with no prior transfusion (relative risk, 4.8; 95% confidence interval, 2.2-10.5). For peak systolic velocity threshold of > or =1.50 multiples of the median, corresponding values in the group with one prior transfusion were 80% and 12.5%, respectively (relative risk, 2.5; 95% confidence interval, 1.2-5.3). There was no risk of severe anemia with a peak systolic velocity below the median for gestation. CONCLUSION: Fetal hydrops is rare, with a hemoglobin deficit of <5 g/dL. In the first such report the main splenic artery peak systolic velocity was noted to be a strong predictor of severe anemia. For the overall population, all such instances could be diagnosed while cordocentesis was performed 22.7% of the time. There is no risk of severe anemia with Doppler peak systolic velocities below the median for gestational age. The measurement is easily obtained and should be investigated as a clinical tool for minimizing the necessity for cordocentesis.     

Accurate prediction of fetal hemoglobin by Doppler ultrasonography

OBJECTIVE: To assess the feasibility of using the middle cerebral artery peak systolic velocity (MCA-PSV) to predict the actual value of fetal hemoglobin in fetuses undergoing a first cordocentesis for detection of anemia caused by maternal red cell alloimmunization. METHODS: Doppler velocimetry of the MCA-PSV was performed in 18 fetuses before an initial cordocentesis. Hemoglobin and MCA-PSV values were expressed as multiples of the median to adjust for the changes that both parameters demonstrate with gestational age. In each fetus we determined: 1) the expected (using a cubic mathematical function describing the correlation between fetal hemoglobin and MCA-PSV) and the observed (determined at the time of the cordocentesis) hemoglobin value; and 2) the percentage differences between the expected and the observed hemoglobin values. RESULTS: Gestational age at the time of the Doppler study ranged from 19 to 31 weeks. On 15 occasions, the fetuses demonstrated anemia. A quadratic relationship was found between the hemoglobin multiples of the median and the percentage differences between the expected and the observed hemoglobin values. As the values of hemoglobin decreased, the percentage difference between expected and observed values significantly decreased (R(2) = 0.48, P <.05). The cubic model estimated fetal hemoglobin well in severely anemic fetuses and less well when the fetus was not anemic. CONCLUSION: Doppler measurement of the MCA-PSV appears to be a valuable tool for estimating hemoglobin concentration in fetuses at risk for anemia. The correlation between hemoglobin and MCA-PSV becomes more accurate as the severity of anemia increases.     

The value of middle cerebral artery systolic velocity for initial and subsequent management in fetal anemia.

OBJECTIVE: To evaluate the fetal middle cerebral artery Doppler waveform for the prediciton of anemia in the RhD-alloimmunized fetus. STUDY DESIGN: Doppler velocimetry of the fetal middle cerebral artery peak systolic velocity was measured in 52 non-hydropic, RhD-alloimmunized fetuses who underwent 103 cordocenteses. Normal values were obtained from 70 normal cases. The peak systolic velocity values were expressed as multiples of the median (MoM) for gestation. Hemoglobin threshold for developing hydrops was developed from 22 RhD-alloimmunized hydropic fetuses and severe anemia was defined as Hb< or =0.60 MoM. The most efficient threshold values for the prediction of severe anemia in groups with no prior transfusion and those with prior transfusion were obtained by constructing ROC curves. RESULTS: The mean gestational age (+/-S.D.) at cordocentesis was 28.0 +/- 4.6 weeks. Severe anemia was noted in 53 (51.5%) occasions. At a threshold middle cerebral artery peak systolic velocity value of > or =1.35 MoM, the sensitivity for severe anemia detection was 100% with a false-positive rate of 18%. In sub-analysis, in patients with one or more prior transfusion a sensitivity of 97% and a false-positive rate of 14% obtained at a threshold of > or =1.45 MoM. In patients with no previous transfusion the sensitivity for severe anemia was 100%, with a false-positive rate of 9.1% at a threshold value of > or =1.35 MoM. CONCLUSION: The middle cerebral artery peak systolic velocity can be used to time both the initial diagnostic procedure and retransfusion.     

Prediction of fetal anemia by middle cerebral artery peak systolic velocity in pregnancies complicated by rhesus isoimmunization.

OBJECTIVES: To study the correlation of peak systolic velocity in the middle cerebral artery with hemoglobin concentration in fetuses at risk of anemia due to Rhesus isoimmunization. DESIGN: Peak systolic velocity of middle cerebral artery (MCA-PSV) was measured before 66 cordocentesis procedures in 20 isoimmunized fetuses. Reference values were derived from a study of 300 control fetuses. MCA-PSV values and hemoglobin concentrations were expressed as multiples of the median (MoM) for gestational age. The following hemoglobin concentration MoM thresholds defined degrees of anemia: mild, between 0.83 and 0.65; moderate, between 0.64 and 0.55; and severe, less than 0.55. Regression analysis was performed and receiver-operator-characteristic curves were constructed to determine the diagnostic accuracy of different thresholds of MCA-PSV for the prediction of moderate to severe anemia, either at the initial or repeat cordocentesis procedures. RESULTS: The mean (+/-SD) gestational age at cordocentesis was 28.5+/-4.6 weeks. Moderate to severe anemia was observed on 29 (44%) and hydrops on 27 (41%) occasions. MCA-PSV correlated weakly with hemoglobin concentrations. At threshold values 1.50 MoM, the sensitivity, specificity, and negative predictive value for moderate to severe anemia were 9.0, 100, and 48.0% at the initial cordocentesis procedures, and 44.0, 96.0, and 73.0% at repeat cordocentesis procedures, respectively. CONCLUSIONS: Although MCA-PSV is highly specific, negative values do not rule out fetal anemia. Further research is required before it can be recommended in clinical practice.     

Fetal anemia: new technologies

PURPOSE OF REVIEW: The purpose of this review is to summarize recently published studies on noninvasive diagnosis of fetal anemia in order to give recommendations for the use of these new tools. RECENT FINDINGS: Red cell alloimmunization remains one of the most common causes of fetal anemia. Amniocentesis and cordocentesis have been used for many years to diagnose fetal anemia due to red cell aloimmunization. These techniques, however, are invasive and many complications are associated with their use. Noninvasive diagnosis of fetal anemia has been performed with Doppler ultrasonography. Based on robust data, several authors recommend the use of middle cerebral artery peak systolic velocity in the management of fetuses at risk for anemia because of red cell alloimmunization. This Doppler parameter can also diagnose fetal anemia due to other conditions. SUMMARY: Middle cerebral artery peak systolic velocity appears to be the best test for the noninvasive diagnosis of fetal anemia. It is important to emphasize that training of sonographers and sonologists is the 'conditio sine qua non' for the correct sampling of the middle cerebral artery.     

Ultrasonographic surveillance in red blood cell alloimmunization

OBJECTIVE: This study was undertaken to audit ultrasonographic measurements of fetal liver length and middle cerebral artery peak velocity in cases of red blood cell alloimmunization between 1986 and 1999. STUDY DESIGN: A total of 200 fetuses at risk for anemia because of red blood cell alloimmunization underwent ultrasonographic measurement of the length of the right lobe of the liver, 45 underwent Doppler recording of middle cerebral artery peak velocity, and 119 underwent fetal blood sampling. RESULTS: The overall survival was 188 of 200 (94%). Among 69 fetuses found to have anemia, liver length values in 64 (93%) were at the 95th percentile or greater, and the other 5 were in the upper part of the normal range. The middle cerebral artery peak velocity was > or =95th percentile in 15 of the 19 cases of anemia in which this value was measured (79%). Among those measured within 1 week of birth, all liver lengths were at least in the upper part of the normal range, with most >95th percentile, including 1 case with a cord blood hemoglobin concentration <90 g/L. CONCLUSIONS: All fetuses with anemia identified at fetal blood sampling had enlarged livers with 93% at > or =95th percentile. The peak velocity in the middle cerebral artery was abnormal in most fetuses with anemia.     

Ultrasonographic monitoring of pregnancies complicated by red blood cell alloimmunization in a cohort with mild to moderate risk according to previous obstetric outcome

AIM: To evaluate the detection rate of fetal anemia and pregnancy outcome as related to our policy of monitoring pregnancies with red blood cell alloimmunization. METHODS: From August 1997 to July 2000 35 pregnant women with maternal red blood cell alloantibodies were monitored by ultrasonographic measurements of the fetal spleen perimeter and peak systolic Doppler flow velocities of the middle cerebral artery, by semiquantification of maternal antibody titers and by general ultrasonographic and clinical evaluation. According to previous obstetric outcome they all had mild to moderate risk of developing fetal anemia. RESULTS: Eleven fetuses were anemic defined as a hemoglobin value < or = 2SD according to gestational age. A spleen perimeter > + 2SD and a middle cerebral artery peak systolic velocity > 95% prediction interval showed sensitivity and specificity of 64 and 92% and 45 and 100%, respectively. The area under receiver operating characteristic curves was 0.926 (95% CI 0.842-1.000; P < 0.001) for the spleen perimeter and 0.837 (95% CI 0.688-0.987; P < 0.01) for the middle cerebral artery peak systolic velocity. Cordocentesis was performed in one pregnancy only. None of the fetuses developed hydrops and all infants survived. Twelve women delivered before 37 weeks gestation. In 10 patients cesarean section was performed due to possible fetal anemia. Six of the 10 neonates had normal hemoglobin values. CONCLUSIONS: The ultrasonographic parameters did not predict all cases of fetal anemia defined as a hemoglobin concentration < or = 2SD according to gestational age. The present policy of monitoring seemed to reduce the number of invasive tests but possibly increased the number of preterm and cesarean deliveries.     

The facts and doubts about the beginning of human life and personality

Objective.?To assess fetal middle cerebral artery (MCA) peak systolic velocity (PSV) in cases of rhesus alloimmunization and to establish whether MCA-PSV is valid for the prediction of fetal anemia.

Methods.?The study population included 157 pregnant women diagnosed with rhesus alloimmunization. MCA-PSV measurements were obtained within 3 days of blood sampling for estimation of hemoglobin concentration either at delivery or cordocentesis by the same operator and by means of the same ultrasound machine using techniques described previously. To evaluate the measurements of the MCA-PSV as the multiples of median (MoM) for gestation we used original nomograms for various gestational ages derived from a group of 273 normal fetuses between 22 and 40 weeks of gestation, not at risk for anemia. Receiver–operator characteristic (ROC) curves were employed to evaluate the relation of the sensitivity (the true positive rate) and the false positive rate (100% specificity) of different threshold values of the MCA-PSV.

Results.?The sensitivity of the MCA-PSV was 94.4% in the case of the subgroup of fetuses with severe anemia. The sensitivity of the MCA-PSV test decreased in less anemic fetuses and was 77.3% in the subgroup with moderate anemia and 32% in the subgroup with mild anemia. According to ROC curves, we selected the optimal MCA-PSV threshold values of 1.15, 1.44, and 1.53 MoM for the prediction of mild, moderate, and severe anemia, respectively.

Conclusions.?MCA-PSV is a significant Doppler index valid for the prediction of moderate and severe fetal anemia.     

Noninvasive diagnosis of anemia in hydrops fetalis with the use of middle cerebral artery Doppler velocity

OBJECTIVE: The purpose of this study was to assess the value of the middle cerebral artery time-averaged mean velocity for the detection of anemia as the cause of fetal hydrops. STUDY DESIGN: We examined 17 pregnant women with fetuses with hydrops (with ascites as the main component of hydrops) and who were considered at risk for anemia because there was no obvious explanation for the hydrops on the initial scan. Assessment included the measurement of the middle cerebral artery time-averaged mean velocity by color flow Doppler scan, followed by fetal blood sampling for investigations that included fetal hemoglobin. We investigated the correlation between increased middle cerebral artery time-averaged mean velocity (>2 SDs for gestational age) and fetal anemia (<2 SDs for gestational age). RESULTS: Eleven fetuses had anemia; 3 of the fetuses had red cell antibodies, and 6 of the fetuses had normal hemoglobin. There was a strong negative correlation between the middle cerebral artery time-averaged mean velocity and the hemoglobin values (r = -.9; P <.0001). The mean (z score) of middle cerebral artery time-averaged mean velocity for fetuses with normal hemoglobin was 1.1 +/- 0.81 and for the fetuses with anemia was 4.71 +/- 2.16 (P <.001). The sensitivity for the increased middle cerebral artery time-averaged mean velocity to predict fetal anemia was 91%, and the specificity was 100%. CONCLUSION: The middle cerebral artery time-averaged mean velocity is significantly increased in cases of hydrops caused by anemia, including cases other than red-cell alloimmunization. These findings can be useful for counseling and treatment and allow the investigation of the cause of hydrops without awaiting blood for intrauterine transfusion in patients who are very unlikely to be anemic and often avoids 2 procedures in those patients who require transfusion. Larger studies are required to further confirm these findings.     

Monitoring of pregnancy complicated by maternal-fetal isoimmunization. A comparison between two clinical protocols

AIM: Invasive techniques such as amniocentesis and cordocentesis are used for the diagnosis and treatment of fetus at risk for anemia due to maternal red-cell alloimmunization. The purpose of this study was to determine the value of non invasive measurements of the peak velocity middle cerebral artery in the fetus (PVMCA) for the diagnosis of fetal anemia. METHODS: From 1996 to September 2002, we studied 23 pregnancies with anti D title >1:32. In the 1(st) group of 11 women (from 1996 to 1999) fetal anemia was detected by invasive techniques (amniocentesis and cordocentesis). In the 2(nd) group of 12 women (from 1999 to 2002) fetal anemia was suspected on the basis of PVMCA. When PVMCA was significantly increased, cordocentesis was performed in order to rule out fetal anemia and to provide in utero transfusions. RESULTS: In the 1(st) period we performed 23 invasive techniques (7 amniocentesis and 16 cordocentesis) in 11 women, but we identified fetal anemia only in 4 cases. In the 2(nd) period we performed only 2 cordocentesis in women in which PVMCA was increased; the blood sampling confirmed fetal anemia in both cases. CONCUSION: PVMCA and fetal hematocrit are highly significantly correlated: high values of PVMCA are associated with fetal anemia. Doppler velocity of PVMCA is related to fetal anemia with positive predictive value 100% and negative predictive value 100%. The middle cerebral artery blood velocity is a non invasive technique for detecting anemia in pregnancies complicated by alloimmunization.     

A comparison between middle cerebral artery peak systolic velocity and amniotic fluid optical density at 450 nm in the prediction of fetal anemia

OBJECTIVE: The purpose of this study was to compare fetal middle cerebral artery peak systolic velocity with amniotic fluid delta optical density at 450 nm in the prediction of fetal anemia. STUDY DESIGN: A prospective study that involved 28 singleton pregnancies that were at-risk for fetal anemia was carried out in a tertiary teaching hospital. Middle cerebral artery peak systolic velocity was measured immediately before the determination of deltaoptical density at 450 nm and fetal hemoglobin concentration. Sensitivities and predictive values for fetal anemia were examined. RESULTS: Fetal hemoglobin concentrations correlated significantly with middle cerebral artery peak systolic velocity (correlation coefficient, -0.77; P <.0001) and deltaoptical density at 450 nm zones (correlation coefficient, -0.56; P =.0025). Middle cerebral artery peak systolic velocity was >1.5 multiples of the median in 15 of 28 cases (54%); for this cutoff value, the sensitivity and positive-predictive values for a hemoglobin deficit of >-3SD were 75% and 60% and for a hemoglobin deficit of >-5SD were 100% and 47%, respectively. The corresponding values for deltaoptical density at 450-nm zone III (6/28 cases, 21%) were 0% (hemoglobin deficit, <-3SD) and 86% and 100% (hemoglobin deficit, <-5SD). CONCLUSION: Middle cerebral artery peak systolic velocity and amniotic fluid optical density at 450 nm are both useful in the prediction of fetal anemia. However, Doppler examination has the advantage of being a noninvasive method that can help reduce the number of invasive procedures in pregnancies that are at-risk for fetal anemia.     

Noninvasive tests to predict fetal anemia: a study comparing Doppler and ultrasound parameters

OBJECTIVE: This study was undertaken to compare test characteristics of ultrasound and Doppler parameters in the prediction of fetal anemia in alloimmunized pregnancies. STUDY DESIGN: In a prospective cohort study, 16 nonhydropic fetuses with red blood cell alloimmunization were evaluated with ultrasound and Doppler imaging. Middle cerebral artery (MCA) peak systolic velocity, intrahepatic umbilical venous (IHUV) maximum velocity, liver length, and spleen perimeter were measured. Results before first fetal blood sampling (FBS) or delivery were analyzed. Fetal anemia was defined as hemoglobin deficit 5 SD or greater. Sensitivity and specificity were calculated. RESULTS: Six fetuses were anemic and required intrauterine transfusion, and 10 were not severely anemic at birth. MCA Doppler imaging was the best predictor of fetal anemia (100%), followed by IHUV (83%). Sensitivity was low for spleen perimeter (66%) and liver length (33%). CONCLUSION: Doppler evaluation of MCA peak systolic velocity is better than IHUV maximum velocity, liver, or spleen size in the prediction of fetal anemia in red blood cell alloimmunization.     

Evaluating suspected fetal anemia with Doppler ultrasound

OBJECTIVE: To evaluate Doppler studies of the fetal middle cerebral artery to predict fetal or neonatal anemia. STUDY DESIGN: The perinatal database at one institution was searched for all patients evaluated for suspected fetal anemia. Middle cerebral artery peak velocity measurements just prior to cordocentesis or the last measurement prior to delivery was used for analysis. The primary outcome data analyzed were fetal or neonatal hematocrit at the time of the cordocentesis or delivery. RESULTS: During the study period there were 36 patients who met the inclusion criterion. There was a significant correlation between middle cerebral artery peak velocity and fetal or neonatal hematocrit. CONCLUSION: Peak flow velocity in the middle cerebral artery is an accurate, noninvasive clinically useful method of evaluating suspected fetal anemia.