Therapeutic management of fetal anemia: review of standard practice and alternative treatment options

Effect of Anti-D titers in RhD-negative pregnant women on fetuses and newborns: A retrospective study

BACKGROUND

Transplacental-derived anti-D IgG in RhD-negative pregnant women can trigger an immune response to Rh D-positive red cells in fetuses and newborns. We assessed the effect of anti-D titers in RhD-negative pregnant women on fetuses and newborns.

METHODS

The clinical data of 142 singleton RhD-sensitized pregnancies were retrospectively collected. The pregnant women received routine prenatal care and the newborns had standard care. Based on the tertile categories of the pregnancies, the maximum titers of anti-D IgG in the pregnant women were divided into three groups ranging from low to high as follows: low-titer group (anti-D titer: 1:4-1:128, n = 57); medium-titer group (anti-D titer: 1:256-1:512, n = 50); and high-titer group (anti-D titer: 1:1024-1:4096, n = 35).

RESULTS

The frequencies of major neonatal complications did not significantly differ among the three groups. The high-titer group had the highest frequency of pregnancies requiring intrauterine transfusion (IUT) and number of IUTs among the three groups. The high-titer group had a significantly higher frequency of newborns treated with top-up transfusion, number of top-up transfusions, frequency of newborns treated with exchange transfusion (ET), and number of ETs when compared to the low-titer group.

CONCLUSION

Higher anti-D titers in RhD-negative pregnant women predict more severe fetal and neonatal hemolytic anemia. Increasing maternal anti-D titers results in an increased need for IUTs, and neonatal top-up transfusions and ETs. Methods for reducing titers of anti-D IgG in RhD-sensitized pregnant women warrants further investigation.

Intrauterine Transfusion for Rhesus Alloimmunization: A Historical Retrospective Cohort from A Single Reference Center in Brazil

Objective: This study aimed to describe the historical experience of a single reference center in Brazil with intrauterine transfusion (IUT) for Rhesus (Rh) alloimmunization, evaluating the major complications and the perinatal outcomes of this procedure. Methods: This retrospective cohort study evaluated data from medical records of pregnant women between 20 and 34 weeks of gestation whose fetuses underwent IUT by cordocentesis between January 1991 and June 2021. The same experienced examiner performed all procedures. Univariate and multivariate logistic regression was used to assess the effect of fetal hydrops, duration of IUT, post-transfusion cord bleeding time, and bradycardia on death (fetal or neonatal). Results: We analyzed data from 388 IUTs in 169 fetuses of alloimmunized pregnant women with a mean age of 29.3 ± 5.1 years. Death and fetal hydrops were significantly associated at first IUT (p < 0.001). We had two cases of emergency cesarean section (mean of 0.51% per IUT) and three cases of premature rupture of the ovular membranes (mean of 0.77% per procedure). Thirty-six deaths were recorded, including 14 intrauterine and 22 neonatal. A higher percentage of neonatal deaths was observed in the group with post-transfusion cord bleeding time > 120 s (45.8%). The odds of neonatal death were 17.6 and 12.9 times higher in cases with hydrops and bradycardia than in cases without hydrops and bradycardia, respectively. The odds of death (fetal and neonatal) were 79.9 and 92.3 times higher in cases with hydrops and bradycardia than in cases without hydrops and bradycardia, respectively. Conclusions: The most common complications of IUT for Rh alloimmunization were post-transfusion cord bleeding, fetal bradycardia, premature rupture of ovular membranes, and emergency cesarean section. The IUT complication most associated with death (fetal and neonatal) was bradycardia, and the perinatal outcomes were worse in fetuses with hydrops.

Pulse wave Doppler ultrasound of umbilical cord in experimentally induced pregnancy toxemia in sheep

Contrary to its widespread use in human cases, the use of Doppler ultrasonography is only recently becoming prevalent in farm animals. This study aimed to determine the effects of maternal metabolic and clinical changes on fetal hemodynamics during pregnancy toxemia with the doppler examination of umbilical cord. In the study twenty ewes with a single healthy fetus were included in the study. At the end of the 120th day of pregnancy, 20 single-bearing pregnant ewes were randomly categorized into two groups. Ewes in the control group were fed to meet all nutritional requirements. On the other contrary, the experimental ewes were fed to meet equivalent to 50 % of the daily needs and then fasted for 96 h. Doppler ultrasonographic examinations of umbilical cord were performed once every two days and once a day during fasting. Beta hydroxybutyric acid (BHBA) concentration was measured by taking blood from sheep on examination days. Pulse systolic velocity (PSV), end diastolic velocity (EDV), PSV/EDV, pulsatility index (PI), resistance index (RI), and fetal heart rate (FHR) as well as BHBA values and how those parameters has changed over time (time by treatment effect) due to energy deprivation during pregnancy were evaluated using repeated measure analysis of variance. No clinical signs were observed in both toxemia and control groups during restricted feeding. BHBA concentration increased and there was a significant time, time by treatment and main effect of treatment effect between groups. No significant main effect of treatment and time by treatment interaction was observed in the changes of PI, RI, FHR, and systolic/diastolic velocity values over time in both groups. FHR was reduced over time, and there was a significant time effect in FHR in both groups. Although doppler indices didn't increase, both PSV and EDV values increased significantly in the pregnancy toxemia group compared with the controls (Time P = 0.03, time by treatment interaction P < 0.05) and the main effect of treatment P < 0.05). The marked increase in blood velocities (PSV and EDV) in the umbilical cord is probably due to the compensatory functioning for excessive energy deprivation of the fetus. Therefore, PSV and EDV might be a valuable indicator for evaluating the fetus's health status during the management of the PT.

Irregular erythrocyte antibodies among antenatal women and their neonatal outcome at a tertiary care hospital in Northern India

BACKGROUND

Red blood cell alloimmunisation during the pregnancy is a significant cause for neonatal mortality and morbidity. This study was planned to determine the prevalence and specificity of irregular erythrocyte antibodies in antenatal mothers and their neonatal outcome.

METHODS

In this observational study, blood grouping and red cell antibody screening of mothers were performed at first visit and after 28 weeks of gestation and positive cases were identified and followed up monthly till delivery by repeating antibody titre and middle cerebral artery-peak systolic velocity. After delivery of alloimmunised mothers, cord blood haemoglobin, bilirubin and direct antiglobulin tests (DAT) were analysed and further outcome of neonate was recorded.

RESULTS

Among 652 registered antenatal cases, 18 multigravida women were found to be alloimmunised, accounting to prevalence of 2.8%. Most common alloantibody identified was anti D (>70%) followed by anti-Le^a, anti-C, anti-Le^b, anti-E and anti-Jk^a. Only 47.7% Rh D negative women received anti-D prophylaxis during previous pregnancies or whenever indicated. DAT was positive in 56.2% of neonates. Among nine DAT positive neonates, two early neonatal deaths due to severe anaemia were observed following birth resuscitation. Four antenatal mothers required intrauterine transfusion in view of fetal anaemia while three neonates received double volume exchange transfusion and top up transfusions after birth.

CONCLUSIONS

This study emphasises importance of red cell antibody screening for all multigravida antenatal women at registration of pregnancy and additionally at 28 weeks or later in high-risk cases irrespective of RhD status.

Fetal surgery

Fetal medicine is a super-specialty enterprise and a technology-driven field. The growth and interest in fetal surgery can be largely attributed to advances in fetal imaging and bespoke instruments for in utero intervention. Previously fatal fetal conditions are now being treated using open surgery, minimally invasive procedures, and percutaneous fetal technologies. Several fetal conditions, including myelomeningocele and twin-to-twin transfusion syndrome, have been tested rigorously in RCTs. However, as the specialty of fetal surgery grows, a robust evidence base with long-term follow-up is obligatory for every procedure. This article offers an overview of fetal surgery and antenatal intervention. As more cutting edge therapies come into clinical practice, growing public opinion and medical ethics will play a significant role in the future of this multidisciplinary specialty.

Therapeutic plasma exchange in pregnancy: A literature review

Therapeutic plasma exchange (TPE) is indicated as a treatment for a wide array of diseases, extensively addressed in the Guidelines of the American Society for Apheresis. In pregnancy, TPE is an uncommon event and application is largely based on extrapolation of efficacy and safety in a non-pregnant population. This review intends to describe the currently available experience of TPE in pregnancy to help clinicians recognise indications during pregnancy and to support current guideline recommendations with literature-based experiences. In order to identify the clinical indications for which TPE is applied in pregnant women, we performed a literature search including studies till November 2019, without a start date restriction. Data extraction included medical indication for TPE and safety of TPE in pregnant women. 279 studies were included for analysis. Nowadays, TPE is predominantly applied for thrombotic microangiopathies, lipid disorders and a variety of autoimmune diseases. The application of TPE during pregnancy remains largely empiric and relies on individual case reports in the absence of high-quality studies and definitive evidence-based guidelines. Safety profile of TPE during pregnancy appears to be comparable to application of TPE in non-pregnant patients. In conclusion, based on the limited evidence that we found in literature with a high risk of publication bias, TPE procedures can be used safely during pregnancy with the appropriate preparation and experience of a multidisciplinary team.

Neonatal outcomes after percutaneous umbilical cord blood sampling†

Objectives: While percutaneous umbilical cord blood sampling (PUBS) and intrauterine transfusion (IUT) are the standards of care for the management of significant fetal anemia, the neonatal complications resultant from these procedures remain poorly understood. Thus, we aimed to compare neonatal outcomes of the patients undergoing percutaneous umbilical cord blood sampling (PUBS) for intrauterine transfusion (IUT) to gestational age- and sex-matched controls with no indication for and not undergoing PUBS.Methods: This was a retrospective matched cohort study at a single institution from 2000 to 2017. Clinical and demographic data were abstracted from the medical record of patients undergoing PUBS. Neonatal outcomes from pregnancies undergoing PUBS for suspected fetal anemia and from randomly selected gestational age- and sex-matched controls were collected. Neonatal outcomes were compared using matched pairs analysis.Results: There were 64 patients who underwent a total of 178 PUBS with 157 IUT. The most common etiology of fetal anemia was anti-D alloimmunization. On an average, patients undergoing PUBS underwent two procedures (IQR 1,4). There were available neonatal outcomes in 40 patients. The median gestational age at delivery was 34 weeks in both neonates who underwent PUBS and controls. In matched pairs analysis, neonates who underwent PUBS were at higher risk for neonatal complications compared to control neonates (92.5 vs. 55%, OR 4.5, 95% CI 4.5, ∞) . Specifically, neonates who underwent PUBS were more likely to experience respiratory complications compared to controls despite a higher uptake of antenatal corticosteroids.Conclusions: We found that neonates who underwent PUBS experience a higher occurrence of complications which does not appear to be secondary to prematurity alone. Despite higher uptake of antenatal corticosteroids in neonates who underwent PUBS as compared to control neonates, neonates who underwent PUBS had a higher risk of respiratory complications. This study can help to inform patients undergoing PUBS/IUT on the anticipated neonatal outcomes and anticipate needed neonatology resources. While PUBS/IUT is the best treatment known to date for management of fetal anemia, our study highlights the need for further research into the subsequent neonatal complications and how to prevent them.

Current perspective and scope of fetal therapy: part 2

Fetal therapy has been defined as any therapeutic intervention either invasive or noninvasive for correcting or treating any fetal malformation or condition. Invasive fetal therapy have its own set of maternal and fetal complications and invasive approach is not feasible in many of fetal conditions that are candidate for fetal therapy. Many such fetal conditions have been treated successfully by medical or noninvasive management. In medical fetal therapy, mothers are treated with medications which are transferred to fetus through placenta and exert positive effect on the fetus, thus avoiding complications that are seen secondary to invasive fetal therapy. The fetal conditions that have been managed with medical therapy includes fetal and neonatal alloimmune thrombocytopenia, neural tube defect, congenital adrenal hyperplasia, perinatal infections, respiratory distress syndrome, inborn error of metabolism, and congenital cystic adenomatoid malformation. This review will cover the medical or noninvasive aspect of fetal therapy and will highlight the progress made in the management of these fetal conditions.

Current perspective and scope of fetal therapy: part 1

Fetal therapy term has been described for any therapeutic intervention either invasive or noninvasive for the purpose of correcting or treating any fetal malformation or condition. Fetal therapy is a rapidly evolving specialty and has gained pace in last two decades and now fetal intervention is being tried in many malformations with rate of success varying with the type of different fetal conditions. The advances in imaging techniques have allowed fetal medicine persons to make earlier and accurate diagnosis of numerous fetal anomalies. Still many fetal anomalies are managed postnatally because the fetal outcomes have not changed significantly with the use of fetal therapy and this approach avoids unnecessary maternal risk secondary to inutero intervention. The short-term maternal risk associated with fetal surgery includes preterm labor, premature rupture of membranes, uterine wall bleeding, chorioamniotic separation, placental abruption, chorioamnionitis, and anesthesia risk. Whereas, maternal long-term complications include risk of infertility, uterine rupture, and need for cesarean section in future pregnancies. The decision for invasive fetal therapy should be taken after discussion with parents about the various aspects like postnatal fetal outcome without fetal intervention, possible outcome if the fetal intervention is done, available postnatal intervention for the fetal condition, and possible short-term and long-term maternal complications. The center where fetal intervention is done should have facility of multi-disciplinary team to manage both maternal and fetal complications. The major issues in the development of fetal surgery include selection of patient for intervention, crafting effective fetal surgical skills, requirement of regular fetal and uterine monitoring, effective tocolysis, and minimizing fetal and maternal fetal risks. This review will cover the surgical or invasive aspect of fetal therapy with available evidence and will highlight the progress made in the management of fetal malformations in last two decades.

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.

The utility of MRI for measuring hematocrit in fetal anemia

BACKGROUND

Doppler ultrasound measurements of the peak systolic velocity of the middle cerebral artery can be used to noninvasively diagnose fetal anemia but are less precise following fetal blood transfusion and in late gestation. We have previously demonstrated the feasibility of estimating fetal hematocrit in vitro using magnetic resonance imaging relaxation times. Here we report the use of magnetic resonance imaging as a noninvasive tool to accurately detect fetal anemia in vivo.

OBJECTIVES

This study has 2 objectives: (1) to determine the feasibility and accuracy of magnetic resonance imaging in estimating hematocrit in anemic fetuses and (2) to compare magnetic resonance imaging and middle cerebral artery Doppler in detecting moderate to severe fetal anemia.

STUDY DESIGN

Fetuses undergoing fetal blood sampling or transfusion underwent magnetic resonance imaging examinations prior to and following their procedures at 1.5 Tesla (Siemens Avanto). A modified Look-Locker inversion pulse sequence and T₂ preparation sequence were applied for T₁ and T₂ mapping of the intrahepatic umbilical vein. Estimated fetal hematocrit was calculated using a combination of T₁ and T₂ values and compared with conventional hematocrit obtained from fetal blood samples and middle cerebral artery Doppler measurements.

RESULTS

Twenty-three fetuses were assessed during 33 magnetic resonance imaging scans. The mean absolute difference between the laboratory and magnetic resonance imaging-estimated hematocrit was 0.06 ± 0.05 with a correlation of 0.77 (P < .001) determined by a multilevel, mixed-effects model adjusting for the repeated measurements from the same participants, multiple gestation pregnancies, and the scan type (ie, before or after transfusion scan). Bland-Altman analysis revealed a systematic bias of -0.03 between the magnetic resonance imaging and fetal blood sampling measurements. Magnetic resonance imaging and middle cerebral artery Doppler had similar sensitivities of approximately 90% to detect moderate to severe anemia. However, magnetic resonance imaging had a higher specificity (93% [13/14], 95% confidence interval, 66-100%) than Doppler (71% [10/14], 95% confidence interval, 42-92%).

CONCLUSION

Moderate to severe fetal anemia can be detected noninvasively by magnetic resonance imaging with high sensitivity and specificity. Our results suggest an adjunct role for magnetic resonance imaging in fetuses with suspected anemia, particularly following previous transfusion and in late gestation.

Current and future role of fetal cardiovascular MRI in the setting of fetal cardiac interventions

Over recent years, technical developments resulting in the feasibility of fetal cardiovascular magnetic resonance (CMR) have provided a new diagnostic tool for studying the human fetal heart and circulation. During the same period, we have witnessed the arrival of several minimally invasive fetal cardiac interventions (FCI) as a possible form of treatment in selected congenital heart diseases (CHDs). The role of fetal CMR in the planning and monitoring of FCI is not yet clear. Indeed, high-quality fetal CMR is not available or routinely offered at most centers caring for patients with prenatally detected CHD. However, in theory, fetal CMR could have much to offer in the setting of FCI by providing complementary anatomic and physiologic information relating to the specific intervention under consideration. Similarly, fetal CMR may be useful as an alternative imaging modality when ultrasound is hampered by technical limitations, for example, in the setting of oligohydramnios and in late gestation. In this review, we summarize current experience of the use of fetal CMR in the diagnosis and monitoring of fetuses with cardiopathies in the setting of a range of invasive in utero cardiac and vascular interventions and medical treatments and speculate about future directions for this versatile imaging medium.

Rh (D) alloimmunization treated by double filtration plasmapheresis

Here in this report a 31 year old pregnant woman with positive serum antiglobulin test against anti-D antierythrocyte antibodies who was treated succesfully with double filtration plasmapheresis (DFPP) is presented. The DFPP was started in the early stage of pregnancy together with intravenous immunoglobulin therapy and the antierythrocyte antibody titer of the patient was successfully maintained in a stable level below 1:64 dilution. She delivered successfully on the 30th week of gestation. The favorable outcome of this patient implies that DFPP is an effective and safe treatment modality in pregnant women with red cell alloimmunization.

Fetal anemia: Diagnosis and management

Fetal anemia has been known for many years as a dangerous complication of pregnancy. Its most common causes are maternal alloimmunization and parvovirus B19 infection, although it can be associated with many different pathological conditions including fetal aneuploidies, vascular tumors, and arteriovenous malformations of the fetus or placenta and inherited conditions such as alpha-thalassemia or genetic metabolic disorders. Doppler ultrasonographic assessment of the peak velocity of systolic blood flow in the middle cerebral artery for the diagnosis of fetal anemia and intravascular intrauterine transfusion for its treatment are the current practice standards. Live birth rates as high as 95% have been reported in recent years. The additional role of intravenous immunoglobulin therapy and the long-term consequences of the condition are the subjects of active ongoing research.

Efficacy of Antenatal Intravenous Immunoglobulin Treatment in Pregnancies at High Risk due to Alloimmunization to Red Blood Cells

Background

Alloimmunization to red blood cells (RBCs) may result in fetal anemia prior to 20 weeks gestation. The question as to whether early commencement of antenatal treatment with high-dose intravenous immunoglobulins (IVIG) may prevent or at least delay the development of fetal anemia in the presence of alloantibodies to RBCs is highly relevant.

Patients and Results

Here we describe a patient with high-titer anti-K and two other severely affected pregnant women with a history of recurrent pregnancy loss due to high-titer anti-D or anti-D plus anti-C. Early commencement of treatment with IVIG (1 g/kg/week) resulted in prevention of intrauterine transfusion (IUT) in the former two cases, and in a significant delay of development of fetal anemia in the remaining case (26 weeks gestation).

Conclusion

Based on our findings and of previously published cases, early initiation of treatment of severely alloimmunized women with IVIG (1 g/kg/week) could potentially improve the outcome of fetuses at risk.

Sonographic Demonstration of Intracranial Hemorrhage in a Fetus with Hydrops Fetalis due to Rh Alloimmunization after Intrauterine Intravascular Transfusion: A Case Report and Review of the Literature

Intrauterine transfusion is the most common and successful intrauterine procedure for the treatment of fetal anemia due to red cell alloimmunization. Fetal intracranial hemorrhage is a very rare complication of intrauterine transfusion in patients with Rh(D) alloimmunization and it has been demonstrated only in a few case reports in the literature. Herein, we described a case of grade IV intraventricular hemorrhage that was diagnosed following the first intrauterine transfusion and reviewed the literature about the fetal intracranial hemorrhage that occurred after intrauterine intravascular transfusion procedure.

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.

Non-invasive evaluation of blood oxygen saturation and hematocrit from T1 and T2 relaxation times: In-vitro validation in fetal blood

PURPOSE

We propose an analytical method for calculating blood hematocrit (Hct) and oxygen saturation (sO₂ ) from measurements of its T₁ and T₂ relaxation times.

THEORY

Through algebraic substitution, established two-compartment relationships describing R1=T1-1 and R2=T2-1 as a function of hematocrit and oxygen saturation were rearranged to solve for Hct and sO₂ in terms of R₁ and R₂ . Resulting solutions for Hct and sO₂ are the roots of cubic polynomials.

METHODS

Feasibility of the method was established by comparison of Hct and sO₂ estimates obtained from relaxometry measurements (at 1.5 Tesla) in cord blood specimens to ground-truth values obtained by blood gas analysis. Monte Carlo simulations were also conducted to assess the effect of T₁ , T₂ measurement uncertainty on precision of Hct and sO₂ estimates.

RESULTS

Good agreement was observed between estimated and ground-truth blood properties (bias = 0.01; 95% limits of agreement = ±0.13 for Hct and sO₂ ). Considering the combined effects of biological variability and random measurement noise, we estimate a typical uncertainty of ±0.1 for Hct, sO₂ estimates.

CONCLUSION

Results demonstrate accurate quantification of Hct and sO₂ from T₁ and T₂ . This method is applicable to noninvasive fetal vessel oximetry-an application where existing oximetry devices are unusable or require risky blood-sampling procedures. Magn Reson Med 78:2352-2359, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

Ascites, anemia and (intestinal) atresia

We report a neonate who presented antenatally with fetal ascites and fetal anemia. The cause of this remained uncertain until 2 weeks later when bowel dilatation was noted on antenatal ultrasound. Clinical signs of intestinal obstruction became evident after delivery, and ileal atresia was found at laparotomy, which was resected with primary anastomosis. Recent reports in the literature have suggested a possible connection between fetal ascites, anemia and dilated bowel with neonatal intestinal obstruction. In these cases and ours, the likely sequence of events was that of in utero midgut volvulus with bleeding into ischemic bowel, hemorrhagic ascites resulting in fetal anemia and progressive bowel dilatation occurring as a consequence of intestinal atresia. Early treatment in our patient with intrauterine blood transfusion may have altered the natural history of her condition, allowing pregnancy to progress to term with a subsequent improved outcome.