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

Fetal NT-proBNP levels and their course in severe anemia during intrauterine treatment

PURPOSE

In adults and fetuses, N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a marker of cardiac failure and myocardial remodelling. We examined the effect of anemia and intrauterine transfusion (IUT) on NT-proBNP concentrations in fetuses with anemia and established gestational age-dependent reference values of a control group.

METHODS

We analyzed NT-proBNP levels in anemic fetuses that underwent serial intrauterine transfusions (IUT), focusing on different causes and severity of anemia and comparing the results to a non-anemic control group.

RESULTS

In the control group, the average NT-proBNP concentration was 1339 ± 639 pg/ml, decreasing significantly with increasing gestational age (R = - 74.04, T = - 3.65, p = 0.001). Subjects had significantly higher NT-proBNP concentrations before initiation of IUT therapy (p < 0.001), showing fetuses with parvovirus B19 (PVB19) infection having the highest concentrations. Hydropic fetuses also showed an increased NT-proBNP concentration compared to non-hydropic fetuses (p < 0.001). During the course of therapy, NT-proBNP concentration before subsequent IUT decreased significantly from pathologically high levels, while MoM-Hb and MoM-MCA-PSV remained pathological.

CONCLUSION

NT-pro BNP levels in non-anemic fetuses are higher than in postnatal life, decreasing with ongoing pregnancy. Anemia is a hyperdynamic state and its severity correlates with circulating NT-proBNP levels. Highest concentrations occur in fetuses with hydrops and with PVB19 infection, respectively. Treatment by IUT leads to a normalisation of NT-proBNP concentrations, so the measurement of its levels may be useful in therapy monitoring.

How do we perform intrauterine transfusions?

BACKGROUND

Intrauterine transfusion (IUT) is an invasive but critical and potentially life-saving intervention for severe fetal anemia with demonstrated improvement in outcomes. The fetus is vulnerable to hemodynamic alterations and transfusion-related adverse events; therefore, special consideration must be given to blood component selection and modification. There is widespread IUT practice variability, and existing guidance primarily relies on expert opinion and single center experiences.

STUDY DESIGN AND METHODS

Experts in Maternal Fetal Medicine, Pediatric Hematology, and Transfusion Medicine from centers across the United States, collectively performing about 120 IUT annually, offer a multidisciplinary perspective on the performance of IUT and preparation of blood components. This perspective includes strategies for identifying an at-risk fetus, communicating between disciplines, determining the necessary blood volume, selecting and processing blood components, documenting the procedure in medical record, and managing the neonate.

RESULTS

Identifying an at-risk fetus relies on review of the clinical history, non-invasive monitoring, and laboratory evaluation. We recommend the use of relatively fresh, group O, cytomegalovirus-safe, freshly irradiated, red blood cells (RBC) that are Hemoglobin S negative and antigen-negative for any maternal antibody, if indicated. These RBC units should be concentrated to remove additives and increase the hematocrit thus minimizing fluctuations in fetal volume status. The units intended for IUT should be labeled clearly and the documentation of transfusion differentiated in the maternal medical record.

DISCUSSION

An awareness of the technical, logistical, and regulatory considerations for IUT performance will facilitate improved communication and patient care, especially when rare units of RBC are required.

Doppler ultrasound in pregnancy - quality requirements of DEGUM and clinical application (part 2)

This second part on Doppler sonography in prenatal medicine and obstetrics reviews its clinical applications. While this has not become the initially anticipated screening tool, it is used for the diagnosis and surveillance of a variety of fetal pathologies. For example, the sonography-based determination of uterine artery blood flow indices is an important parameter for the first trimester multimodal preeclampsia risk assessment, increasing accuracy and providing indication for the prophylactic treatment with aspirin. It also has significant implications for the diagnosis and surveillance of growth-restricted fetuses in the second and third trimesters through Doppler-sonographic analysis of umbilical artery, middle cerebral artery and ductus venosus. Here, especially the hemodynamics of the ductus venosus provides a critical criterium for birth management of severe, early-onset FGR before 34 + 0 weeks of gestation. Further, determination of maximum blood flow velocity of the middle cerebral artery is a central parameter in fetal diagnosis of anemia which has been significantly improved by this analysis. However, it is important to note that the mentioned improvements can only be achieved through highest methodological quality. Importantly, all these analyses are also applied to twins and higher order multiples. Here, for the differential diagnosis of specific complications such as TTTS, TAPS and TRAP, the application of Doppler sonography has become indispensable. To conclude, the successful application of Doppler sonography requires both exact methodology and precise pathophysiological interpretation of the data.

Performance of middle cerebral artery doppler for prediction of recurrent fetal anemia

OBJECTIVE

To assess the predictive value of middle cerebral artery Doppler peak systolic velocity (MCA-PSV) for moderate-severe fetal anemia following one intrauterine transfusion (IUT) and test the performance of alternate cutoffs to the recommended threshold ≥1.69 multiples of the median (MoM).

METHODS

This was a retrospective cohort study of patients with pregnancies affected by alloimmunization who underwent percutaneous umbilical blood sampling (PUBS) procedures from 2000 to 2020. An MCA-PSV ≥1.69 MoM was the indication for the second IUT. The primary outcome was recurrent moderate-severe fetal anemia. Receiver-operating characteristic (ROC) curves assessed the predictive ability of MCA-PSV for the primary outcome and the Youden index identified the "optimal" cutoff value. Predictive characteristics of MCA-PSV ≥1.69 MoM and the "optimal" cutoff were compared.

RESULTS

Of the 58 patients who underwent IUT during the study period, 36 (62%) did not meet inclusion criteria. Of the remaining 22 patients who underwent a second PUBS, 12 (54.6%) fetuses had moderate or severe anemia. Following one IUT, the AUC for MCA-PSV was 0.86 (95% CI 0.70-1.00) for the primary outcome. The "optimal" cutoff MCA-PSV value was 1.74 MoM, which had a greater specificity than ≥1.69 MoM (90 vs. 50%, p = .05), but was not statistically significant. The sensitivity was similar between the two cutoff values of ≥1.69 and ≥1.74 MoM (83.3 vs. 75.0%, p = .65) (Table 2).

CONCLUSION

Raising the recommended MCA-PSV cutoff to ≥1.74 MoM for recurrent moderate-severe fetal anemia after one IUT would decrease the number of unnecessary procedures without significantly changing the sensitivity of this screening test.

Peak systolic velocity of fetal middle cerebral artery to predict anemia in Red Cell Alloimmunization in un-transfused and transfused fetuses

OBJECTIVE

To assess the accuracy of middle cerebral artery peak systolic velocity (MCA-PSV) in prediction of severe fetal anemia resulting from Red Cell Alloimmunization (Anti-D) in un-transfused and transfused fetuses. In addition to comparing the accuracy of MCA-PSV and the estimation of the daily decline of fetal hemoglobin (Hb), to determine the appropriate time of subsequent transfusions.

STUDY DESIGN

This was a retrospective study of a series of 84 anaemic fetuses due to Red Cell alloimmunization. During each in-utero transfusion session, measurements of (1)MCA-PSV, (2)pre- and (3)post-transfusion Hb levels were recorded. Receiveroperating characteristics (ROC) curves, negative and positive predictive values of MCA-PSV in predicting severe fetal anemia were calculated. Regression analysis assesses the correlation between fetal HB and MCA-PSV, and between observed and expected fetal hemoglobin levels.

RESULTS

Eighty four anemic fetuses were included in the study and had an in-utero transfusion. The positive predictive value (PPV) of MCAPSV decreased sharply from 86.0 % at the first IUT, to 52.0 % and 52.1 % at the second and third IUTs respectively. According to the ROC curves, setting the cut-off at 1.70 MoM would provide the best performance of MCA-PSV with respect to the timing of the second and third IUT. Setting a higher threshold of 1.70 MoM for the 2nd and 3rd transfusions would increase the PPV from 52.0 % to 96.4 % at the second IUT, and from 52.1%-99.8 % at the third IUT.

CONCLUSION

In this study we suggest that a higher MCA-PSV (MoM 1.7 in compared to 1.5MOM) can accurately predict the recurrence of severe fetal anemia requiring serial IUTs. In transfused fetuses, MCAPSV accuracy to detect severe anemia decline slightly with increase number of IUT. In addition to that, the mean projected daily decrease in fetal hemoglobin has a similar accuracy to MCA-PSV in predicting moderate to severe fetal anemia.

A rare case of intra-uterine blood transfusion for fetal anemia caused by a giant placental chorioangioma

Objectives

Chorioangiomas (CAs) are the most frequent tumor-like-lesions of the placenta. Giant CAs (more than 4–5 cm in diameter) is rare and may result in severe maternal fetal complications.

Case presentation

A 38-year-old multigravida presented at 31 weeks’ gestation with contractions. Upon evaluation, contractions were spontaneously ceased, and the cervix was closed. Ultrasound examination revealed a single viable fetus, polyhydramnios and a 75 x 48 x 82 mm vascular lesion located on the placental surface near the cord insertion. Doppler assessment was suggestive of fetal anemia with middle cerebral artery-peak systolic velocity (MCA-PSV) 1.8 MoM’s. Fetal heart rate monitoring and biophysical scores were reassuring. Following betamethasone fetal cord sampling that revealed fetal hemoglobin level of 8.8 g/dL, 57 cc of blood was transfused resulting in final hemoglobin level of 14.3 g/dL measured prior to needle extraction. MCA-PSV was normalized immediately after the procedure, however aggravated at the following day with MCA-PSV 65 cm/s (1.46 MoM’s). No other intervention was taken and MCA-PSV continued to fluctuate from slight to severe anemia spontaneously over a period of two weeks. At 34 gestational weeks, the women delivered a healthy baby. Fetal hemoglobin level at delivery was 21 g/dL.

Conclusions

Fetal blood transfusion is a reasonable treatment for fetal anemia in cases of giant chorioangiomas. Following transfusion, MCA-PSV may act unexpectedly reflecting various mechanisms affecting the flow.

Is fetal middle cerebral artery peak systolic velocity correlated with hemoglobin levels in cases of nonimmune fetal anemia?

OBJECTIVES

To establish whether a correlation exists between the fetal middle cerebral artery peak systolic velocity (MCA PSV) and fetal hemoglobin levels before intrauterine transfusion (IUT) in cases of severe fetal anemia.

METHODS

This was a single-center, retrospective study of data from 49 fetuses treated with IUT for fetal anemia between 2003 and 2018. Severe fetal anemia was suspected when MCA PSV was or exceeded 1.55 multiples of the median.

RESULTS

The causes of anemia were largely idiopathic, and the overall survival rate was 57%. MCA PSV and hemoglobin were correlated in all 34 fetuses with alloimmune fetal anemia, whereas the 15 fetuses with nonimmune causes showed no correlation. Of the 15 noncorrelated cases, twin pregnancy was most common, followed by idiopathic causes. All the twin pregnancies involved monochorionic twins. Fetal hydrops, especially ascites, was significantly associated with severe anemia.

CONCLUSIONS

Fetal MCA PSV may not be a reliable independent factor for the diagnosis of severe fetal anemia in nonimmune cases, and the presence of associated hydrops implies that the fetus is more likely to have severe fetal anemia than in a fetus without hydrops.

Diagnostic Performance of Doppler Ultrasonography for the Detection of Fetal Anemia: A Meta-analysis

This study evaluates the diagnostic performance of Doppler ultrasound in diagnosing fetal anemia. Data were taken from relevant study reports published in peer-reviewed journals identified after a literature search in electronic databases. Random effects meta-analyses were performed by pooling the effect sizes of diagnostic indices (sensitivity, specificity, positive/negative predictive values, and false-positive rate) or correlation coefficients reported by individual studies. As a result, 31 studies (1848 pregnancies; gestation age, 28.25 weeks [95% confidence interval {CI}, 26.87-29.63]) were included in the meta-analysis. Anemia was found in 63.7% (95% CI, 49.7-77.7) fetuses, and severe anemia was found in 36.7% (95% CI, 26.9-46.4) fetuses. Sensitivity and specificity of Doppler ultrasound for detecting fetal anemia in alloimmunized fetuses at middle cerebral artery peak systolic velocity cutoff of 1.5 multiple of median for gestation age were 83.42% (95% CI, 71.75-95.09) and 80.30% (95% CI, 73.58-87.02), respectively. Positive predictive value, negative predictive value, and false-positive rate were 76.35% (95% CI, 65.98-86.72), 80.0% (95% CI, 76.63-83.37), and 10.4% (95% CI, 5.9-14.9), respectively. Correlation coefficient between hematological anemia and Doppler ultrasound-measured blood flow velocity was -0.706 (95% CI, -0.765 to -0.635; P < 0.00001). In conclusion, Doppler ultrasound-measured middle cerebral artery peak systolic velocity at 1.5 multiple of median provides good diagnostic strength for the detection of alloimmunized fetal anemia. A strong correlation between Doppler velocimetric measures and hematological anemia is also observed.

Prediction of Fetal Anemia in Subsequent Transfusions: Is There a Need to Change the Threshold of the Peak Systolic Velocity of the Middle Cerebral Artery?

INTRODUCTION

Peak systolic velocity (PSV) of the middle cerebral artery (MCA) shows 100% sensitivity for predicting fetal anemia before the first intrauterine transfusion (IUT). However, its ability to predict subsequent transfusions has remained mostly controversial.

OBJECTIVES

To assess if there is a need to change the threshold of MCA-PSV from 1.5 to 1.69 multiples of the median (MoM) to predict fetal anemia and the need for subsequent IUT.

METHODS

This is a retrospective audit, wherein case records of mothers who underwent IUT at the Bangalore Fetal Medicine Centre between April 2008 and May 2017 were reviewed; 86 cases were included, and the data were analyzed using MS Excel. The MCA-PSV and pretransfusion Hb were converted into MoM. 40 fetuses that had more than 1 IUT were included in the analysis. -Results: 31/40 fetuses that had >1 IUT had an MCA-PSV >1.5 MoM, of which 29 were anemic according to the post-IUT Hb MoM. 20/29 (69%) had an MCA-PSV >1.69, whereas 9/29 (31%) had an MCA-PSV between 1.5 and 1.69 MoM. Our study shows that changing the MCA-PSV threshold from 1.5 to 1.69 MoM will reduce the detection of fetal anemia and hence the need for repeat IUT by 31%.

CONCLUSIONS

Increasing the fetal MCA-PSV threshold from 1.5 to 1.69 will miss out one-third of the fetuses that will require a 2nd, 3rd, or 4th IUT. This is more relevant in geographical areas where the parents must travel long distances for IUTs, which are performed in tertiary fetal care centers.

Performance of fetal middle cerebral artery peak systolic velocity for prediction of anemia in untransfused and transfused fetuses: systematic review and meta-analysis

OBJECTIVE

To evaluate the performance of fetal middle cerebral artery peak systolic velocity (MCA-PSV) ≥ 1.5 multiples of the median (MoM) for the prediction of moderate-severe anemia, in untransfused and transfused fetuses.

METHODS

A systematic search was performed to identify relevant observational studies reported in the period 2008-2018 that evaluated the performance of MCA-PSV, using a threshold of 1.5 MoM for the prediction of fetal anemia. Diagnosis of fetal anemia by blood sampling was the reference standard. A hierarchical summary receiver-operating characteristics (hSROC) curve was constructed using random-effects modeling. Subgroup and meta-regression analyses, according to the number of previous intrauterine transfusions, were performed.

RESULTS

Twelve studies and 696 fetuses were included in the meta-analysis. The area under the hSROC curve (AUC) for moderate-severe anemia was 83%. Pooled sensitivity and specificity (95% CI) were 79% (70-86%) and 73% (62-82%), respectively, and positive and negative likelihood ratios were 2.94 (95% CI, 2.13-4.00) and 0.272 (95% CI, 0.188-0.371). When considering only untransfused fetuses, prediction improved, achieving an AUC of 87%, sensitivity of 86% (95% CI, 75-93%) and specificity of 71% (95% CI, 49-87%). A decline in sensitivity for the prediction of moderate-severe anemia by MCA-PSV ≥1.5 MoM was observed (estimate, -5.5% (95% CI, -10.7 to -0.3%), P = 0.039) as the number of previous transfusions increased.

CONCLUSIONS

MCA-PSV ≥ 1.5 MoM for the prediction of moderate-severe anemia in untransfused fetuses shows moderate accuracy (86% sensitivity and 71% specificity), which declines with increasing number of intrauterine transfusions. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Clinical Characteristics of Jra Alloimmunization in Pregnancy: A Case Series

Only few studies have reported on Jra alloimmunization in pregnancy, and its clinical course remains unclear. We reviewed our cases to clarify the change in the peak systolic velocity of the middle cerebral artery (MCA-PSV) during pregnancy and the critical anti-Jra antibody titer to predict fetal anemia. We collected the data of pregnant women with anti-Jra antibody from two hospitals between 2010 and 2017. We extracted data on maternal information, number of intrauterine blood transfusions (IUT), trend of anti-Jra antibody titer, changes of MCA-PSV, and neonatal outcome. We had 16 cases. IUTs were performed in 6 fetuses with severe anemia between 27 and 32 weeks' gestation. The MCA-PSV did not increase more than 1.5 multiples of the median (MoM) after 32 weeks' gestation. No significant difference was found in the maximum titer between cases with IUT and those without IUT. All pregnancies but one delivered at term. No neonates developed severe anemia or jaundice. MCA-PSV did not increase higher than 1.5 MoM later during the pregnancy. A critical titer to predict fetal anemia did not exist. Spontaneous term delivery could be expected even in fetuses who underwent IUT before 32 weeks' gestation.

Correlation of fetal blood vessel Doppler measurements with fetal anemia among Rhesus isoimmunized pregnancies after two intrauterine transfusions

OBJECTIVE

To assess the correlation between fetal blood vessel Doppler measurements and fetal anemia among Rhesus isoimmunized pregnancies after two intrauterine transfusions as a potential guide to therapy.

METHODS

A prospective observational study was conducted among 30 women who attended a single hospital in India between April 2, 2015 and October 30, 2016. The participants underwent a third intrauterine transfusion based on a middle cerebral artery (MCA) peak systolic velocity (PSV) of greater than 1.50 multiples of the median (MoM). Cordocentesis was performed before the third intrauterine transfusion and hematocrit values correlated with the blood vessel Doppler measurements.

RESULTS

The MCA PSV MoM and fetal hematocrit MoM had a correlation coefficient of -0.43 (95% confidence interval -0.68 to 0.08; P=0.017). The sensitivity, specificity, positive predictive value, and negative predictive value were 68%, 57%, 83%, and 33%, respectively. The descending aorta PSV δ and fetal hematocrit δ had a correlation coefficient of -0.54 (95% confidence interval -0.75 to -0.23; P=0.001). An area under the curve of 0.80 (standard error 0.085; P=0.017) had 87% sensitivity and 57% specificity for diagnosing fetal anemia.

CONCLUSION

The descending aorta PSV could offer a useful diagnostic adjunct to MCA PSV after two intrauterine transfusions.

Fetal anemia

The diagnosis and management of fetal anemia has been at the forefront of advances in the fields of fetal physiology, immunology, fetal imaging, and fetal therapy among others. Alloimmunization and parvovirus infection are the leading cause of fetal anemia in the United States. The middle cerebral artery peak systolic velocity (MCA-PSV) diagnoses fetal anemia. Its discovery is considered one of the most important achievements in fetal medicine. Accumulation of experience in recent years as well as refinement of surgical techniques have led to safer invasive procedures. It is expected that long term follow-up of affected pregnancies, continues to reflect all these improvements in care. It is also expected that treatment of other less common causes of fetal anemia becomes more frequently reported and that the management principles of fetal anemia are successfully applied to other fetal pathologies.

Does an intrauterine exchange transfusion improve the fetal prognosis in parvovirus infection cases?

BACKGROUND

Almost 20% of parvovirus B19 foetal infections require intrauterine transfusions. In addition, myocardial dysfunction has been observed in severe parvovirus B19 infections. One objective of an intrauterine exchange transfusion (IUET) is to avoid an overload during the transfusion. Our aim was to study the obstetrical and neonatal outcomes in cases of IUETs performed for foetal parvovirus infections and to compare our survival rate to those studies in which simple in utero transfusions were chosen.

STUDY DESIGN AND METHODS

This was a retrospective monocentre study of all patients followed up for parvovirus B19 infections in which IUETs were performed. An IUET was indicated when foetal hydrops was observed and/or when severe foetal anaemia was diagnosed though an elevation in the middle cerebral artery peak systolic velocity. The characteristics of each pregnancy and the neonatal outcomes were studied until hospital discharge.

RESULTS

Thirty-five IUETs were performed in 26 foetuses. The median gestational age of the first IUET was 22.6 weeks. Only one foetal bradycardia incidence was recorded during the procedure. Three medical pregnancy terminations were observed in our series, secondary to severe cerebral anomalies confirmed in the magnetic resonance imaging. Five in utero deaths occurred, in which 2 of the foetuses underwent multiple IUETs. All the neonates had normal haemoglobin levels at birth, and none were transferred to the neonatal intensive care unit. The overall survival rate was 70%.

CONCLUSION

IUETs exhibit a survival rate similar to that of simple intrauterine transfusions in foetal parvovirus infection cases.

The Recurrence Risk of Fetomaternal Hemorrhage

Massive fetomaternal hemorrhage (FMH) can cause devastating pregnancy outcomes. Perinatal prognosis may be improved by intrauterine transfusion, but the appropriate management for these pregnancies remains unclear. To determine the recurrence risk of FMH after intrauterine transfusion, we performed a systematic review of all case reports/series of patients with proven FMH treated with intrauterine transfusion and who had subsequent follow-up of at least 72 h until delivery. This revealed 13 cases, with 1 additional case from our institution. Ten patients (71.4%) had a second episode of FMH requiring a second intrauterine transfusion. Five patients (35.7%) required at least 3 intrauterine transfusions. The time interval between intrauterine transfusions was progressively reduced. The gestational age at the onset of signs/symptoms was 26.6 ± 2.1 weeks, and gestational age at delivery was 34.2 ± 4.2 weeks. Two cases of fetal demise (14.3%) and no neonatal deaths were recorded. Limited postnatal follow-up on 8 neonates was normal. The mean neonatal hemoglobin and transfusion rates were 13.2 ± 5.7 g/dL and 33.3%, respectively. Close fetal monitoring, likely daily, is necessary to recognize FMH recurrence. Several transfusions may be necessary once FMH is diagnosed if pregnancy is allowed to continue > 72 h.

Resolution of maternal Mirror syndrome after succesful fetal intrauterine therapy: a case series

Background

Mirror syndrome (MS) is a rare obstetric condition usually defined as the development of maternal edema in association with fetal hydrops. The pathogenesis of MS remains unclear and may be misdiagnosed as pre-eclampsia.

Case presentation

We report a case series of MS in which fetal therapy (intrauterine blood transfusion and pleuroamniotic shunt) resulted in fetal as well as maternal favourable course with complete resolution of the condition in both mother and fetus.

Conclusions

Our case series add new evidence to support that early diagnosis of MS followed by fetal therapy and clinical maternal support are critical for a good outcome.

Fetal middle cerebral artery Doppler to time intrauterine transfusion in red-cell alloimmunization: a randomized trial

OBJECTIVES

To evaluate whether Doppler measurement of middle cerebral artery peak systolic velocity (MCA-PSV) for timing subsequent intrauterine transfusions (IUTs) in fetuses that had undergone one IUT for anemia secondary to red-cell alloimmunization is non-inferior to timing based on expected decrease in fetal hematocrit (Hct) or fetal hemoglobin level, without compromising infant hemoglobin at birth.

METHODS

This was an international, pragmatic multicenter randomized controlled trial. Women with a pregnancy complicated by fetal anemia secondary to red-cell alloimmunization (due to any antibody alone or in combination), as indicated by the need to undergo a single IUT, were eligible for inclusion. Women were randomized to the determination of timing of further transfusion(s) by Doppler measurement of MCA-PSV (MCA-PSV Group), with a serial upward trend of values >1.5 multiples of the median considered indicative of the need for another IUT, or timing of transfusion by a decrease in fetal Hct (fetal Hct Group), with subsequent IUTs timed according to an estimated fall in fetal Hct of 1% per day or fetal hemoglobin of 0.3 g/dL per day, to maintain fetal hemoglobin level between 7 and 10 g/dL. The primary outcome was infant hemoglobin level measured at birth.

RESULTS

A total of 71 women were randomized, 36 to the MCA-PSV Group and 35 to the fetal Hct Group. Median gestational age at randomization was 30.3 weeks, the majority of women were Caucasian and non-smokers, 9.9% of women had Kell alloimmunization, and 14% of fetuses were hydropic at their first IUT. No statistically significant differences between the two treatment groups were observed with regard to mean hemoglobin levels at birth (MCA-PSV Group, 10.36 ± 3.82 g/dL vs fetal Hct Group, 12.03 ± 3.14 g/dL; adjusted mean difference -1.56 g/dL (95% CI, -3.24 to 0.13 g/dL); P = 0.070), or the number of IUTs performed after randomization (MCA-PSV Group, 1.75 ± 1.79 vs fetal Hct Group 1.80 ± 1.32; adjusted relative risk 0.88 (95% CI, 0.61-1.26); P = 0.474). There was no statistically significant difference between the two groups with respect to the risk of adverse infant outcomes related to alloimmunization or procedure-related complications.

CONCLUSION

Both Doppler measurement of MCA-PSV and estimation of the decrease in fetal Hct or hemoglobin can be used to determine the timing of second and subsequent IUTs in fetuses with red-cell alloimmunization. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Management of red blood cell alloimmunization in pregnancy

The main cause of fetal anemia is maternal red blood cell alloimmunization (AI). The search of maternal antibodies by indirect antiglobulin test allows screening for AI during pregnancy. In case of AI, fetal genotyping (for Rh-D, Rh-c, Rh-E and Kell), quantification (for anti-rhesus antibodies) and antibody titration, as well as ultrasound monitoring, are performed. This surveillance aims at screening for severe anemia before hydrops fetalis occurs. Management of severe anemia is based on intrauterine transfusion (IUT) or labor induction depending on gestational age. After intrauterine transfusion, follow-up will focus on detecting recurrence of anemia and detecting fetal brain injury. With IUT, survival of fetuses with alloimmunization is greater than 90% but 4.8% of children with at least one IUT have neurodevelopmental impairment.

Intrauterine Fetal Blood Transfusion: Descriptive study of the first four years' experience in Oman

OBJECTIVES

Haemolytic disease of the fetus and newborn (HDFN) causes hydrops fetalis. The successful treatment of HDFN has been reported with intrauterine blood transfusion (IUT). This study aimed to describe the initial experience with IUT procedures in Oman.

METHODS

This retrospective observational study took place at the Royal Hospital and Sultan Qaboos University Hospital Blood Bank, Muscat, Oman, and included all women who underwent IUT procedures in Oman between March 2012 and March 2016. Gestational and neonatal outcomes were assessed, including complications, morbidity, neurodevelopmental sequelae and mortality.

RESULTS

A total of 28 IUT procedures for 13 fetuses carried by 11 women were performed. Gestational age at the time of referral ranged from 13-30 weeks, while the median gestational age at first IUT procedure was 26 weeks (range: 19-30 weeks). Indications for the procedure included HDFN caused by anti-D (n = 6), a combination of anti-D and anti-C (n = 4), anti-K (n = 1) and anti-Jsb (n = 1) antibodies and nonimmune hydrops fetalis due to a congenital parvovirus infection (n = 1). Median fetal haemoglobin levels at the beginning and end of the procedure were 4.6 g/dL and 12.8 g/dL, respectively. Most procedures were transplacental intravascular transfusions through the placental umbilical cord root (71.4%), followed by transamniotic intravascular transfusions (14.3%). The overall survival rate was 61.5%, with five deaths; of these, four were intrauterine and one was an early neonatal death due to non-resolved hydrops and severe cardiac dysfunction.

CONCLUSION

As a relatively novel obstetric procedure in Oman, IUT seems to result in a favourable outcome for hydropic fetuses.

Fetomaternal hemorrhage complicated pregnancy: risks, identification, and management

PURPOSE OF REVIEW

This article aims not only to review recent literature about the clinical features of massive fetomaternal hemorrhage (FMH) and identification of risk factors, but also to alert obstetricians and pediatricians to this underdiagnosed and underestimated severe obstetrical issue. In addition, a simplified flow chart for the antenatal management of suspected FMH is proposed.

RECENT FINDINGS

Improvements in obstetrical and neonatal care have decreased perinatal morbidity and mortality and the rate of stillbirth. Unfortunately, because of the nonspecific signs on presentation, adverse outcome associated with massive FMH has not followed this trend and still has devastating consequences. As even the definition varies among publications and there is lack of universal screening, the real nature still remains obscure. Improvements in the diagnosis of fetal anemia, laboratory and intrauterine transfusion techniques, and the implementation of prenatal and postnatal neuroprotection give some hope for the better outcome in the most severe cases. Unfortunately, obstetricians' awareness of the massive FMH remains still at an unacceptably low level.

SUMMARY

There is an urgent need for the internationally accepted definition, standardized pregnancy management protocol, and structured follow-up of neonates from such pregnancies. We suggest the international registry of massive FMH cases.

Determination of optimal timing of serial in-utero transfusions in red-cell alloimmunization

OBJECTIVES

To assess the performance of middle cerebral artery peak systolic velocity (MCA-PSV) and of the expected daily decrease in fetal hemoglobin in determining the timing of serial in-utero transfusions (IUT) in red-cell alloimmunization.

METHODS

This was a retrospective study of a continuous series of suspected anemic fetuses undergoing IUT between June 2003 and December 2012. Doppler measurement of MCA-PSV and pre- and post-transfusion hemoglobin levels were recorded at the time of the first, second and third IUT. Receiver-operating characteristics (ROC) curves and negative and positive predictive values of MCA-PSV in the prediction of severe fetal anemia were calculated. The daily decrease of fetal hemoglobin (Hb) between IUTs was calculated. Regression analysis was used to assess the correlation between pretransfusion fetal hemoglobin and MCA-PSV, and between observed and expected (by projection of daily decreases) pretransfusion fetal hemoglobin levels.

RESULTS

One hundred and eleven fetuses required an IUT, of which 96 and 67 received a second and third IUT, respectively. The area under the ROC curve for MCA-PSV in the prediction of severe fetal anemia was not different for each rank of transfusion. The positive predictive value of MCA-PSV decreased from 75.3% at the first IUT, to 46.7% and 48.8% at the second and third IUTs, respectively, while the negative predictive value for a 1.5-MoM threshold remained high (88.9% at the second and 91.7% at the third IUT). The mean daily decrease in hemoglobin following each transfusion was 0.45, 0.35 and 0.32 g/dL, respectively. There was a persistent linear correlation between fetal hemoglobin and MCA-PSV and between observed and expected fetal hemoglobin levels.

CONCLUSIONS

Both MCA-PSV and projection of daily decrease in hemoglobin are reliable means of diagnosing fetal anemia following previous IUTs. The high negative predictive value of MCA-PSV could allow subsequent IUTs to be postponed in selected cases.

Society for Maternal-Fetal Medicine (SMFM) Clinical Guideline #8: the fetus at risk for anemia--diagnosis and management

OBJECTIVE

We sought to provide evidence-based guidelines for the diagnosis and management of fetal anemia.

METHODS

A systematic literature review was performed using MEDLINE, PubMed, EMBASE, and the Cochrane Library. The search was restricted to English-language articles published from 1966 through May 2014. Priority was given to articles reporting original research, in particular randomized controlled trials, although review articles and commentaries were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion. Evidence reports and published guidelines were also reviewed, and additional studies were located by reviewing bibliographies of identified articles. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology was used for defining the strength of recommendations and rating the quality of evidence. Consistent with US Preventive Task Force guidelines, references were evaluated for quality based on the highest level of evidence.

RESULTS AND RECOMMENDATIONS

We recommend the following: (1) middle cerebral artery peak systolic velocity (MCA-PSV) measured by ultrasound Doppler interrogation be used as the primary technique to detect fetal anemia; (2) amniotic fluid delta OD450 not be used to diagnosis fetal anemia; (3) MCA-PSV assessment be reserved for those patients who are at risk of having an anemic fetus (proper technique for MCA-PSV evaluation includes assessment of the middle cerebral artery close to its origin, ideally at a zero degree angle without angle correction); (4) if a fetus is deemed at significant risk for severe fetal anemia (MCA greater than 1.5 multiples of the median or hydropic), fetal blood sampling be performed with preparation for an intrauterine transfusion, unless the pregnancy is at a gestational age when the risks associated with delivery are considered to be less than those associated with the procedure; (5) if a fetus is deemed at significant risk for severe fetal anemia, the patient be referred to a center with expertise in invasive fetal therapy; (6) MCA-PSV be considered to determine the timing of a second transfusion in fetuses with anemia, and, alternatively, a predicted decline in fetal hemoglobin may be used for timing the second procedure; and (7) pregnancies with a fetus at significant risk for fetal anemia be delivered at 37-38 weeks of gestation unless indications develop prior to this time.

A pilot study on peak systolic velocity monitoring of fetal anemia after administration of chemotherapy during pregnancy

OBJECTIVES

To monitor fetal anemia during administration of chemotherapy to the fetus's mother.

STUDY DESIGN

Between 2007 and 2012 six patients with malignancy diagnosed during pregnancy were included in our prospective study. For evaluation of fetal anemia, peak systolic velocimetry (PSV) of the middle cerebral artery is considered the best method. The patients were repeatedly examined one day before and on the third day after the administration of chemotherapy. At least three measurements were performed and the highest value was used as appropriate. Multiples of the median (MoM) were calculated using the website http://www.perinatology.com/calculators/MCA.htm. When the MoM reached 1.29, moderate anemia was diagnosed.

RESULTS

The women's average age was 30 years. The average gestational age at diagnosis was 20.7 weeks of pregnancy. Borderline fetal anemia was detected in only in one patient. After delivery newborns were examined by standard pediatric evaluation and blood count was provided. There was no evidence of any newborn anemia.

CONCLUSIONS

Chemotherapy administered during pregnancy is becoming more frequent due to increasing knowledge and data on such cases. Close monitoring of the fetus should be performed in specialized centers. For detection of chemotherapy-induced anemia, PSV measurement should be employed.

Two intrauterine rescue transfusions in treatment of severe fetomaternal hemorrhage in the early third trimester

KEY CLINICAL MESSAGE

When massive fetomaternal hemorrhage is diagnosed in the early third trimester of pregnancy, serial fetal intravascular transfusion may be an alternative to immediate delivery.

Doppler in obstetrics: beyond the umbilical artery

Doppler analysis of the umbilical and uterine arteries has long been performed in perinatal medicine to assess fetal health and maternal risk for preeclampsia. Several other vessels can be interrogated to obtain additional, vital information. Velocimetry in the fetal middle cerebral artery can yield evidence of the presence or absence of anemia and, in cases of delayed growth, of the risk of hypoxic damage. Ductus venosus waveforms are a very good indicator of impeding fetal jeopardy and should be used when umbilical artery waveforms become abnormal. Early pregnancy uterine artery Doppler reflects the status of the placental vasculature and, as such, is an excellent tool for predicting the risk of preeclampsia or intrauterine growth restriction.

Intrauterine blood transfusion in immune hydrops fetalis, corrects middle cerebral artery Doppler velocimetry very quickly

The aim of our study was to evaluate the middle cerebral artery velocimetry before and after intrauterine blood transfusion in immune hydrops fetalis. The current study was conducted in a tertiary research hospital, from February 2009 to January 2011. Nineteen intrauterine blood transfusions performed during the study period. The factors recorded were age of the mothers, gestational weeks, pre-transfusion fetal hematocrit and post-transfusion fetal hematocrit, and also middle cerebral artery peak systolic velocimetry (MCA-PSV) was detected and recorded before and after intrauterine transfusion. A control group of twenty two cases for normal MCA doppler velocimetry was also included to the study. During the study, a total of eleven rhesus isoimmunized pregnancies underwent intrauterine blood transfusions at our perinatal diagnose unit. Before transfusion seventeen severe and two moderate anemias were detected and mean MoM of MCA-PSV was 1.76±0.38 MoM. Post transfusion mean MoM of MCA-PSV in the patient group and control group were 1.08±0.22 MoM and 0.96±0.21 MoM, respectively. The mean MCA-PSV values were higher in RI fetuses than post transfusion and control group. In current study, we found that MCA-PSV is a valuable parameter in detecting fetal anemia requiring intrauterine transfusion and mean MCA-PSV values is higher than 1.5 MoM in fetuses with anemia. And also decrease in MCA-PSV just after transfusion in anemic fetuses showed the quick response of the fetus to correction of anemia.

The MCA Doppler and its role in the evaluation of fetal anemia and fetal growth restriction

Doppler velocimetry of the middle cerebral artery (MCA) has played a major role in fetal medicine for the last 23 years, both in intrauterine growth-restricted (IUGR) and anemic fetuses. Its utility in the diagnosis and management of cases of fetal anemia was initially demonstrated in cases of red cell alloimmunization and later extended to other types of anemia. In addition, MCA Doppler studies are crucial in the evaluation of IUGR fetuses. This article is a review of the role of the MCA in these 2 conditions.

Sonographic findings in severe fetomaternal transfusion

Fetomaternal hemorrhage (FMH) or fetomaternal transfusion syndrome is the leakage of fetal red blood cells into the maternal circulation. Massive FMH can cause substantial fetal morbidity and mortality. Sonographic evidence of severe FMH syndrome includes fetal hydrops and other fetal anemia-related findings. The peak systolic velocity in the middle cerebral artery has extensively been used for the prediction of fetal anemia and for the timing of the first intrauterine intravascular transfusion (IIVT). We present a case of severe FMH syndrome that was diagnosed during the 24th week of pregnancy. A total of eight IIVT were performed. The actual increase in the fetal Hb after each transfusion was much lower than the expected. At 27 weeks of gestation, sonographic evaluation revealed areas of echogenicity around the posterior horns of the lateral ventricles suggesting ischemic damage. Due to these findings, no further IIVTs were offered and the fetus died a week later. The management of fetal anemia caused by severe FMH is difficult, and the anemic fetuses do not respond well to serial IIVTs as the transfer of blood to the maternal circulation continues.

Anemia and cerebral outcomes: many questions, fewer answers

A number of clinical studies have associated acute anemia with cerebral injury in perioperative patients. Evidence of such injury has been observed near the currently accepted transfusion threshold (hemoglobin [Hb] concentration, 7-8 g/dL), and well above the threshold for cerebral tissue hypoxia (Hb 3-4 g/dL). However, hypoxic and nonhypoxic mechanisms of anemia-induced cerebral injury have not been clearly elucidated. In addition, protective mechanisms which may minimize cerebral injury during acute anemia have not been well defined. Vasodilatory mechanisms, including nitric oxide (NO), may help to maintain cerebral oxygen delivery during anemia as all three NO synthase (NOS) isoforms (neuronal, endothelial, and inducible NOS) have been shown to be up-regulated in different experimental models of acute hemodilutional anemia. Recent experimental evidence has also demonstrated an increase in an important transcription factor, hypoxia inducible factor (HIF)-1alpha, in the cerebral cortex of anemic rodents at clinically relevant Hb concentrations (Hb 6-7 g/dL). This suggests that cerebral oxygen homeostasis may be in jeopardy during acute anemia. Under hypoxic conditions, cytoplasmic HIF-1alpha degradation is inhibited, thereby allowing it to accumulate, dimerize, and translocate into the nucleus to promote transcription of a number of hypoxic molecules. Many of these molecules, including erythropoietin, vascular endothelial growth factor, and inducible NOS have also been shown to be up-regulated in the anemic brain. In addition, HIF-1alpha transcription can be increased by nonhypoxic mediators including cytokines and vascular hormones. Furthermore, NOS-derived NO may also stabilize HIF-1alpha in the absence of tissue hypoxia. Thus, during anemia, HIF-1alpha has the potential to regulate cerebral cellular responses under both hypoxic and normoxic conditions. Experimental studies have demonstrated that HIF-1alpha may have either neuroprotective or neurotoxic capacity depending on the cell type in which it is up-regulated. In the current review, we characterize these cellular processes to promote a clearer understanding of anemia-induced cerebral injury and protection. Potential mechanisms of anemia-induced injury include cerebral emboli, tissue hypoxia, inflammation, reactive oxygen species generation, and excitotoxicity. Potential mechanisms of cerebral protection include NOS/NO-dependent optimization of cerebral oxygen delivery and cytoprotective mechanisms including HIF-1alpha, erythropoietin, and vascular endothelial growth factor. The overall balance of these activated cellular mechanisms may dictate whether or not their up-regulation leads to cytoprotection or cellular injury during anemia. A clearer understanding of these mechanisms may help us target therapies that will minimize anemia-induced cerebral injury in perioperative patients.

Relationship between Cardiofemoral Index and the plasma concentration of brain natriuretic peptide in anemic fetuses associated with Rh alloimmunization

BACKGROUND

Fetal anemia is a common result of alloimmunization and is an important cause of fetal congestive heart failure resulting in heart dilation. Fetuses suspected of having heart failure present a higher Cardiofemoral Index and an increase in plasma BNP levels, because the cardiac hormonal system is activated by increased heart wall stretch due to increased left ventricular volume and pressure overload.

METHODS

Our group studied 33 pregnant women (22-31 weeks' gestation at the first cordocentesis) referred for intrauterine fetal transfusion due to severe red blood cells isoimmunization. Up to 6 h prior to each cordocentesis, all fetuses were submitted to ultrasonography measurements where the Cardiofemoral Index was calculated. Samples of blood from the umbilical vein were collected for hemoglobin concentration and blood gas measurements. Plasma levels of BNP were determined with the use of plasma that had previously been frozen and thawed once. Plasma BNP was measured by radioimmunoassay. Pearson's correlation test and regression analysis were used to determine the association between the plasma concentration of BNP and the Cardiofemoral Index of the anemic fetuses with RH alloimmunization.

RESULTS

Anemia was severe in 17 (50%) fetuses, mild in 9 (26.47%) and in 8 patients (23.53%) the fetuses were not anemic; hemoglobin ranged from 3.10 to 15.70 g/dl. The Cardiofemoral Index ranged from 0.43 to 0.87 and it was altered (>or=0.59) in 23 fetuses. A significant positive correlation was observed between BNP plasma fetal concentration and Cardiofemoral Index (Pearson r=0.61, P<0.0001).

CONCLUSIONS

These results suggest that fetal plasma concentration of BNP may increase in fetuses with heart dilation leading to a positive association between Cardiofemoral Index and plasma concentration of BNP.

The usefulness of middle cerebral artery Doppler assessment in the treatment of the fetus at risk for anemia

The use of Doppler ultrasound evaluation to measure the peak systolic velocity of the fetal middle cerebral artery (MCA) has been a major breakthrough in the noninvasive detection of fetal anemia. An elevated peak MCA velocity of >1.5 multiples of the median is useful in the timing of the initial intrauterine transfusion (IUT) in the red cell-alloimmunized pregnancies. Data reported to date suggest that a threshold of 1.32 multiples of the median can be used to time the second IUT; the MCA Doppler evaluation does not appear sensitive for the timing of subsequent IUTs in these pregnancies. The peak MCA velocity has also proved useful in the detection of other anemic states that include Kell alloimmunization, fetal parvovirus infection, fetomaternal hemorrhage, alphathalassemia, and after-laser therapy for twin-twin transfusion.

Fetal anaemia: diagnosis and management

Fetal anaemia can by treated by in-utero therapy, which results in a significant improvement in perinatal outcome. The important causes of fetal anaemia are rhesus alloimmunisation, kell alloimmunisation and parvovirus infection. At-risk pregnancies require serial monitoring to ensure timely intervention with intrauterine transfusion. Non-invasive testing with middle cerebral artery Doppler is becoming the monitoring modality of choice.

Anaemia and the brain

PURPOSE OF REVIEW

This article reviews the physiological and pathophysiological effects of anaemia on the brain, focusing on the hypothesis that anaemia-induced cerebral hypoxia contributes to anaemic cerebral dysfunction and injury. It also reviews evidence that the regulated increase in cerebral blood flow observed during anaemia represents a compensatory neuroprotective mechanism invoked to optimize cerebral oxygen delivery, thereby protecting the brain from hypoxic injury.

RECENT FINDINGS

Severe anaemia, or low haematocrit, has been associated with cognitive dysfunction, impaired cerebral vascular regulation, neurological injury, and increased mortality, which suggests that the brain is vulnerable to anaemia-induced injury. Reduced cerebral tissue oxygen tension has been measured directly at haemoglobin concentrations near 35 g/l, suggesting that hypoxia may contribute to anaemic cerebral injury. A demonstration of increased hypoxic cerebral gene expression, including neuronal nitric oxide synthase, may provide a more sensitive means of determining the minimum haemoglobin concentration at which anaemia-induced cerebral hypoxia can be detected. The measurement of increased cerebral cortical neuronal nitric oxide synthase messenger RNA and protein levels in rats, at haemoglobin concentrations between 50 and 60 g/l, suggests that cerebral hypoxia occurred at these higher haemoglobin concentrations. Mechanisms regulating anaemic cerebral vasodilation and increased cerebral oxygen delivery, including nitric oxide, require further elucidation to establish their role in protecting the brain during anaemia.

SUMMARY

Characterization of mechanisms of anaemia-induced cerebral injury will contribute to the development of optimal therapeutic strategies for anaemic patients. Such strategies would include a clearer definition of transfusion triggers based on physiological endpoints. The overall goal of these efforts would be to minimize morbidity and mortality associated with anaemia.

Fetal hematocrit decrease after repeated intravascular transfusions in alloimmunized pregnancies

BACKGROUND

The aim of this study is to evaluate the fetal hematocrit (Hct) decrease along repeated intravascular intrauterine fetal transfusions (IUTs) and test the hypothesis that, after consecutive IUTs, there is a lower Hct drop off.

METHODS

From July 1996 to June 2006, pregnancies submitted to IUT for fetal hemolytic anemia treatment had their data assessed. The daily rate of decrease in fetal Hct was calculated by dividing the difference between the posttransfusion Hct of the previous IUT and the pretransfusion Hct of the current IUT, by the number of days between the transfusions. Fetuses with other abnormalities or submitted to intraperitoneal transfusions were excluded.

RESULTS

Eighty-one women were submitted to IUT during the alluded period, ensuing 296 intrauterine transfusions. The perinatal survival was 89.9% (n = 80), with 92.0% (n = 69) of nonhydropic fetuses survival. Hydropic fetuses showed higher hematocrit drop off than nonhydropic ones (P < 0.01). Compared to the interval between the first and second IUT, the daily fetal Hct decline was lower after the third one (P < 0.05). Stratifying by the presence of hydrops, nonhydropic fetuses showed a smaller decrease at the third and fourth intervals (P < 0.01 and P < 0.05, respectively). Among hydropic fetuses, there is a trend of smaller Hct decrease along successive IUTs (interval 3, P = 0.08; interval 4, P = 0.07; and interval 5, P = 0.10).

CONCLUSIONS

Following some IUTs, fetal hematocrit decrease is lower and larger intervals between the transfusions could be accomplished. Multicenter studies should investigate an algorithm for timing subsequent IUTs, considering Doppler values, estimated fetal hematocrit decline and other parameters.