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.     

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.     

Predicción de anemia fetal por isoinmunización tras transfusiones intrauterinas. Revisión de los casos tratados en nuestra unidad

Objetive

Evaluate the intrauterine blood transfusions performed in fetuses with anemia due to red blood cell alloimmunization in our unit and the detection rate of the middle cerebral artery Doppler to predict anemia after the first transfusion.

Material and methods

We performed 53 intrauterine blood transfusions in 15 patients with red blood cell alloimmunization. We analyze the characteristics of the cases and the value of the middle cerebral artery Doppler to predict fetal anemia.

Results

The detection rate of fetal anemia with the peak systolic velocity Doppler in the middle cerebral artery was 85% after the first transfusion and 72% after the second or more. There were no false positive results of the test in our series.

Conclusions

Doppler evaluation of the middle cerebral artery as predictor of fetal anemia has a lower detection rate after consecutive transfusions.     

Flow velocity waveforms of the vascular system in the anemic fetus before and after intravascular transfusion for severe red blood cell alloimmunization

Sixteen intravascular transfusions were performed in 16 anemic human fetuses. To investigate the status of the vascular system with Doppler ultrasonography before and after correction of anemia, pulsatility index values were obtained for the flow velocity waveforms of the middle cerebral artery, internal carotid artery, anterior cerebral artery, thoracic aorta, abdominal aorta, renal artery, femoral artery, and umbilical artery before and the day after the correction of anemia. The fetuses were divided into two groups: (1) fetuses with a hematocrit level between 2 and 4 SDs below the normal mean value for gestational age and (2) fetuses with a hematocrit value less than 4 SDs below the normal mean value for gestational age. No significant differences were observed in the pulsatility index values of the vessels studied before and after correction of anemia in both groups of fetuses. These data suggest that the pulsatility index cannot be used as an indicator of fetal anemia at the hematocrit values studied.     

A case of monochorionic twin pregnancy complicated with intrauterine single fetal death with successful treatment of intrauterine blood transfusion in the surviving fetus

We report a case of monochorionic twin pregnancy complicated with single fetal demise that received successful treatment of intrauterine transfusion for severe anemia of the surviving fetus. A single fetal demise occurred at 20 weeks of gestation and middle cerebral artery peak systolic velocity (MCA-PSV), a marker for fetal anemia, showed marked elevation in the surviving fetus. Fetal blood sampling was immediately done and severe fetal anemia (hemoglobin = 5.5 g/dl, hematocrit = 16.8%) was confirmed, and then intrauterine transfusion was performed. After transfusion, MCA-PSV rapidly decreased to the normal value and remained within normal range until delivery. A healthy 2,640 g male infant was delivered at 35 weeks of gestation without anemic status and no neurological problem was found at 1-year old. The present report supports that intrauterine rescue transfusion is a useful treatment to prevent the adverse outcome of surviving fetus in monochorionic twin pregnancy complicated with single fetal demise, and monitoring of MCA-PSV is also useful to assess anemic status of the surviving fetus.     

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.     

Two hundred intrauterine exchange transfusions in severe blood incompatibilities

Two hundred intrauterine exchange transfusions were performed under local anesthesia in 107 cases of blood incompatibilities (60 fetuses with severe anemia and 47 with hydrops). Under sonographic guidance, depending on fetal and placental position, an optimal puncturing site was selected along the umbilical vein: placental insertion, fetal insertion, or fetal intraabdominal segment. Tests were immediately performed to confirm fetal origin of blood obtained and estimate hemoglobin level. Blood used for exchange transfusion was compatible with maternal blood and had a hematocrit value of 75%. Exchange transfusion was continued until a hemoglobin level of 16 gm/dl was reached. This procedure was first associated with intraperitoneal transfusions and was subsequently used independently once a month to maintain an adequate hemoglobin level. In 4 fetuses with hydrops, antenatal regression of this sign was observed in 33 cases (70.2%). Overall outcome of 107 fetuses after exchanges was 84 living neonates (78.5%), 15 deaths in utero, and eight neonatal deaths. The survival rate was 91.6% for fetuses without hydrops and 61.7% for those with hydrops. The advantage of exchange transfusion appears to be rapid and efficient correction of anemia with elimination of incompatible fetal red blood cells.     

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.     

Management of rhesus alloimmunization in pregnancy

Rhesus immune globulin has decreased the prevalence of rhesus D alloimmunization in pregnancy so that only approximately six cases occur in every 1,000 live births. The rarity of this condition warrants consideration of consultation with or referral to a maternal-fetal medicine specialist with experience in the monitoring and treatment of patients with red cell alloimmunization in pregnancy. Evaluation for the presence of maternal anti-D antibody should be undertaken at the first prenatal visit. First-time sensitized pregnancies are followed with serial maternal titers and, when necessary, serial Doppler assessment of the peak systolic velocity in the middle cerebral artery. In cases of a heterozygous paternal genotype, new DNA techniques now make it possible to diagnose the fetal blood type through free fetal DNA in maternal plasma. When there is a history of an affected fetus or infant, maternal titers are no longer predictive of risk in subsequent pregnancies. Serial peak middle cerebral artery velocities using Doppler ultrasonography can be used in these pregnancies to detect fetal anemia. In some situations, intrauterine transfusion is necessary through ultrasound-directed puncture of the umbilical cord with the direct intravascular injection of red cells. Perinatal survival rates of more than 90% have been reported; hydrops fetalis reduces the chance for a viable outcome by up to 11%. Neonatal and infant outcomes are complicated by the need for repeated transfusions secondary to suppressed erythropoiesis. Long-term studies have revealed normal neurologic outcomes in more than 90% of cases. Future therapy will involve selective modulation of the maternal immune system, making the need for intrauterine transfusions a rarity.     

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.     

Pulsed Doppler flow-velocity waveforms before and after intrauterine intravascular transfusion for severe erythroblastosis fetalis

Pulsed Doppler studies of the fetal and maternal circulations were carried out before and after 64 intrauterine transfusions performed on 24 fetuses. A model was derived for the prediction of hematocrit before the first transfusion: Hematocrit = 7.778 - (0.088 x peak velocity in descending aorta) + (0.968 x gestational age [weeks]) - (10.911 if hydrops present) (r = 0.876, p less than 0.0001). An alternative formula, excluding hydrops, was slightly less predictive: Hematocrit = 45.312 - (56.261 x umbilical cord Pourcelot index) - (0.128 x peak velocity in descending aorta) + (1.042 x gestational age) r = 0.822, p less than 0.001). Neither model was accurate in the prediction of hematocrit before second or subsequent transfusions. A third model was derived from second-transfusion data: Hematocrit = 40.524 - (0.045 x peak velocity in descending aorta) - (10.693 x pulsatility index of maternal uterine artery) (r = 0.81, p less than 0.003). However, this model was unable to predict hematocrit before third or later transfusions. No changes in Doppler parameters before and after transfusion were found. We conclude that pulsed Doppler ultrasound may be helpful in the evaluation of isoimmunized pregnancies, in differentiating anemic from normal fetuses. It does not appear to be useful in determining the timing of later transfusions. The lack of change before and after transfusions suggests that these vessels will not provide significant information concerning the effect of rapid volume and hematocrit changes in the fetus.     

Flow velocity waveforms of the umbilical and cerebral arteries before and after intravascular transfusion

Thirteen intravascular transfusions were performed in 13 human fetuses who were anemic because of severe red-cell alloimmunization. To investigate the status of the umbilical and cerebral circulations by pulsed Doppler ultrasound, we studied the fetal middle cerebral artery (N = 13), internal carotid artery (N = 11), anterior cerebral artery (N = 11), and umbilical artery (N = 13) before, within the first 2 hours after, and the day after intravascular transfusion. The gestational age at the time of transfusion was 21-31 weeks (mean +/- SD 25 +/- 3.1). The fetal hematocrits before transfusion ranged from 12-32% (23.4 +/- 6.1), whereas the hematocrit after transfusion was between 25-42% (35 +/- 5). The net blood volume transfused (volume infused--volume removed) ranged between 7.5-31.0 mL (16.0 +/- 7.4). The hematocrit of the transfused blood varied between 68-81% (74 +/- 4). Repeated-measures analysis of variance indicated significant differences in the pulsatility index values of the four vessels studied. The same analysis indicated significant differences in the pulsatility index values at the three time points. Multiple comparison tests showed that the pulsatility index was reduced significantly immediately after transfusion for each vessel studied, but returned to pretransfusion levels by the next day. These data suggest a change in vascular impedance soon after transfusion as a consequence of direct intravascular transfusion.     

Correlación entre el grado de anemia fetal intertransfusional y la medición Doppler de la velocidad máxima del flujo en la arteria cerebral media en la anemia hemolítica por isoinmunización Rh

ObjectiveTo evaluate the correlation between peak velocity in the middle cerebral artery (V_maxMCA) and the degree of fetal anemia and its potential predictive value of fetal anemia in three patients with red-cell alloinmunizationMaterial and methodA prospective study in three cases of fetal anemia secondary to red-cell alloinmunization managed with intrauterine blood transfusion. Intertransfusional follow-up and the decision to perform new cordocenteses were based on the presence of ultrasonographic signs of hydrops and the estimation of the rate of hemolysis after transfusions. V_maxMCA were measured pre and post, and between blood transfusionsResultsA total of 11 blood transfusion were performed. There was an inverse correlation between V_maxMCA and the degree of anemia. The sensitivity of the V_maxMCA to detect moderate and severe anemia was 100%. In our patients the inclusion of the V_maxMCA in our protocols would have avoided 3 cordocentesisConclusionsOur preliminary results suggest the potencial value of the measurement of the peak flow velocity in the MCA for the follow-up of fetal anemia between transfusions in cases of hemolytic anemia due to red-cell alloinmunization     

The fetal cardiovascular response to antenatal steroids in severe early-onset intrauterine growth restriction

OBJECTIVE: Our aim was to study the hemodynamic effects of betamethasone on fetuses with intrauterine growth restriction (IUGR) with absent or reversed end-diastolic (ARED) umbilical artery flow. STUDY DESIGN: Color/pulsed Doppler waveforms were obtained before and after intramuscular injections of betamethasone in 19 consecutive fetuses with IUGR/ARED and 6 control fetuses. Peak velocities and pulsatility index (PI) values were obtained from the umbilical (UA) and middle cerebral (MCA) arteries and intrahepatic umbilical vein (UV). RESULTS: Ten ARED fetuses developed transient positive umbilical end-diastolic flow after steroids, whereas nine fetuses showed persistent ARED. The persistent ARED subgroup demonstrated increased UA and UV peak velocities after steroids, which may indicate fetal hypertension. Fetal death (n=2) and severe acidosis (n=2) were confined to the subgroup with persistent ARED. CONCLUSION: Preterm IUGR/ARED fetuses exhibit divergent cardiovascular responses to prenatal steroids. Intensive Doppler-based fetal monitoring may identify a subset of fetuses prone to decompensation after maternal steroid administration.     

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.     

Increasing the noninvasive management of rhesus isoimmunization

OBJECTIVE: To determine the clinical outcome of isoimmunized pregnancies managed by middle cerebral artery peak systolic velocity (MCA-PSV) in an intention-to-treat study. METHOD: Rhesus isoimmunized pregnancies were managed with serial ultrasound and Doppler studies at 7-day intervals up to 34 weeks of gestation, between 2001 and 2005. Invasive diagnostic and therapeutic procedures were carried out when MCA-PSV was indicative of moderate or severe anemia. RESULTS: The overall sensitivity in detecting moderate to severe fetal anemia at less than 34 weeks was 100% (95% confidence interval, 54.1-100.0 L). Twenty-two cases were managed with MCA-PSV. Twelve cases needed fetal blood sampling and 6 cases needed intrauterine transfusion. Cordocentesis revealed a hematocrit of more than 26% in 6 fetuses. CONCLUSION: Management by MCA-PSV Doppler at weekly intervals is a highly sensitive method for detecting fetal anemia. It reduces the number of fetal blood samples needed and significantly lowers interventional procedures.     

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.     

Doppler measurements of blood flow in the middle cerebral artery for the diagnosis of fetal anemia

OBJECTIVES: This paper presents a possibility of non-invasive diagnosis of fetal anemia based on the Doppler assessing of peak systolic velocity (PSV) in the fetal middle cerebral artery. The results of Doppler measurements were compared with fetal peripheral blood count estimated after cordocentesis. MATERIALS AND METHODS: Doppler measurements of blood flow velocity in the fetal middle cerebral artery were performed in years 2000 and 2001 in 22 pregnancies complicated by maternal blood group alloimmunisation. Gestation age varied from 27 to 36 weeks, the mean gestation age was 32 weeks. Depending on hemoglobin concentration in the fetal blood sample the severity of anemia was divided into three groups: severe anemia (Hb = < 7 g%), middle (Hb = = 8-10 g%) and light (Hb = = 10-12 g%). The fourth group consisted of fetuses without anemia (Hb > 12 g%). The results were statistically analyzed to estimate correlation between the Doppler blood flow indexes (PI, RI, SD and PSV) in the middle cerebral artery and the peripheral blood count (Hb, Ht, erythrocyte count) of fetal blood received by cordocentesis. Using T-Student-test the differences of average maximal blood flow velocities and mean Doppler indexes in the group of fetuses with severe anemia (Hb < 7 g%) and fetuses without anemia (Hb > 12 g%) were compared. RESULTS: Highest (negative) correlation was found between the peak systolic velocity and the fetal hemoglobin concentration. The correlation index was -0, 85, which means the higher the peak systolic velocity the lower the hemoglobin concentration. The difference between the mean peak systolic velocity in the group of fetuses with severe anemia and the group without anemia was statistically significant (p < 0.001). However, there was no statistical significant difference in the mean peak systolic velocity between the group with middle anemia (Hb = 10-12 g%) and the group without anemia (Hb > 12 g%). CONCLUSIONS: Doppler ultrasonography with the measurement of peak systolic velocity in the middle cerebral artery is a good method in evaluating of fetal peripheral blood count. Non-invasive peak systolic velocity measurements in the middle cerebral artery allow to assess the fetal hemoglobin concentration and also to reduce the count of diagnostic cordocentesis.     

The Effect of Fetal Intravascular Blood Transfusion on Plasma Endothelin Levels in Fetuses With Rhesus Alloimmunization

Objective: To determine if intrauterine intravascular fetal transfusion affects fetal umbilical venous endothelin levels.Methods: Endothelin concentrations were measured by radioimmunoassay in fetal umbilical venous blood obtained immediately before and after 36 fetal transfusions performed for Rh alloimmune hemolytic anemia. Umbilical venous pressures also were recorded before and after transfusion.Results: The mean (± standard deviation [SD]) gestational age at transfusion was 27.0 ± 4.6 weeks, whereas the initial and post-transfusion hematocrits were 23.3 ± 8.5% and 41.8 ± 6.3%, respectively. Post-transfusion endothelin levels correlated significantly with the volume of transfused blood (r = .41; P = .03) and with post-transfusion increases in umbilical vein pressure (r = .86; P < .001). Among fetuses undergoing initial transfusion, there were significant differences between mean (± SD) pre- and post-transfusion endothelin levels [3.6 (± 2.2) pg/mL versus 6.3 (± 4.0) pg/mL, respectively; P = .02]. In contrast, among fetuses undergoing a repeat fetal transfusion, no differences in mean (± SD) pre- versus post-transfusion endothelin levels were observed [3.8 (± 1.8) pg/mL versus 2.2 (± 1.77) pg/mL, respectively; P = .3)]. Step-wise multiple regression analysis identified order of transfusion as a significant predictor of change in endothelin levels from pre- to post-transfusion measurements (adjusted r² = .26; P = .003).Conclusion: Rapid expansion of fetal intravascular volume by intravenous transfusion of packed red blood cells with a high hematocrit enhances fetal endothelin levels in those fetuses undergoing initial but not subsequent transfusions.     

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.