Doppler ultrasonography versus amniocentesis to predict fetal anemia

The use of free DNA for fetal RHD genotyping in the Rh negative pregnant patient-the time has come

Cell-free DNA to determine the fetal RHD genotype from the maternal circulation was first described in 1993. High throughput assays using polymerase chain reaction technology were introduced in Europe and gained widespread acceptance in the management of the Rhesus alloimmunized pregnancy. The specificity and sensitivity of these assays approached 99%. As confidence was gained with these results, Scandinavian countries began to employ cell-free DNA for fetal RHD typing as an integral component of their introduction of antenatal Rhesus immune globulin in non-alloimmunized pregnancies. Since 40% of RhD-negative pregnant women will carry an RhD-negative fetus, doses of Rhesus immune globulin were conserved. Recently 2 U.S. companies have introduced cell-free DNA assays for RHD as part of their noninvasive prenatal testing assays. Both utilize next generation sequencing and have developed methodologies to detect the aberrant RHD pseudogene and the hybrid RHD-CE-Ds genotype. In addition, excellent correlation studies with either neonatal genotyping or serology have been reported. The manufacturer of RhoGAM has recently announced a national shortage. Given the current availability of reliable cell-free DNA assays for determining the RHD status of the fetus, the time has come to implement this strategy to triage the antenatal use of Rhesus immune globulin in the U.S.

Confirmatory Middle Cerebral Artery Doppler Testing in Alloimmunized Patients with Suspected Fetal Anemia

OBJECTIVE

This article aimed to evaluate pregnancy outcomes when a plan to perform fetal blood sampling (FBS) or delivery was based solely on the first abnormal middle cerebral artery peak velocity (MCA-PV) measurement compared with making a plan after a confirmatory test on a subsequent day.

STUDY DESIGN

We performed a descriptive study of pregnancy outcomes including all patients in a single healthcare system with maternal red cell alloimmunization undergoing ultrasound between 2005 and 2017 who had at least one MCA-PV>1.5 multiples of the median (MoM). We excluded patients with any sign of hydrops prior to the index visit or abnormal MCA-PV at>35 weeks. The first exam with a MCA-PV>1.5 MoM was deemed the index visit.

RESULTS

Fifty patients were identified. Twenty-one patients underwent intervention (FBS or delivery) based on the first abnormal MCA-PV. Of those, 9 had moderate or severe anemia (positive predictive value [PPV]: 43%), while 12 had mild or no anemia. The other 29 patients underwent a confirmatory MCA test between 2 and 8 days later. Of these, 13 patients had an abnormal confirmatory test and 11 of these underwent FBS and 7 had moderate or severe anemia (PPV: 54%). Sixteen patients undergoing confirmatory MCA Doppler had a normal test on repeat and did not undergo FBS. Of those, none developed moderate or severe anemia.

CONCLUSION

A substantial number of patients (55%) had normal MCA-PV testing on repeat, allowing avoidance of invasive testing. Deferring FBS until the abnormal MCA-PV was confirmed was not associated with undetected moderate or severe anemia.

KEY POINTS

· False-positive results from MCA-PV Doppler prediction of fetal anemia are common.. · Repeat noninvasive testing is normal in many patients with suspected fetal anemia.. · Invasive fetal testing can often be safely avoided by performing a confirmatory Doppler exam ination..

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.

First intrauterine transfusion in Rh isoimmunised triplet pregnancy

G3P2L1, 28+4 weeks of gestation rhesus (Rh) isoimmunised pregnant women, was referred with trichorionic triamniotic triplet pregnancy with Rh antibody titres of 1:32. Nuchal translucency and anomaly scan were within normal limits with no major malformation for any of the fetuses. Obstetric colour Doppler with middle cerebral artery peak systolic volume revealed foetal anaemia in all three fetuses having velocities corresponding to around 1.5 times the median. Decision of intrauterine transfusion of blood to all three fetuses was taken. Access to fetuses was challenging and expertise in interventional ultrasound was required for transfusion. The patient tolerated the procedure well and eventually went on to deliver uneventfully at 34 weeks of gestation for worsening pre-eclampsia. After birth, all three triplets received triple-surface intensive phototherapy and intravenous immunoglobulin at a dosage of 1 g/kg. Phototherapy was gradually reduced and discontinued within 72 hours, and the infants were discharged from the neonatal intensive care unit at 96 hours of age.

Current Insights Into K-associated Fetal Anemia and Potential Treatment Strategies for Sensitized Pregnancies

K-associated anemic disease of the fetus and newborn (K-ADFN) is a rare but life-threatening disease in which maternal alloantibodies cross the placenta and can mediate an immune attack on fetal red blood cells expressing the K antigen. A considerably more common disease, D-associated hemolytic disease of the fetus and newborn (D-HDFN), can be prophylactically treated using polyclonal α-D antibody preparations. Currently, no such prophylactic treatment exists for K-associated fetal anemia, and disease is usually treated with intrauterine blood transfusions. Here we review current understanding of the biology of K-associated fetal anemia, how the maternal immune system is sensitized to fetal red blood cells, and what is understood about potential mechanisms of prophylactic HDFN interventions. Given the apparent challenges associated with preventing alloimmunization, we highlight novel strategies for treating sensitized mothers to prevent fetal anemia that may hold promise not only for K-mediated disease, but also for other pathogenic alloantibody responses.

Accuracy of a portable hemoglobinometer (HemoCue) to measure fetal hemoglobin values during in utero transfusion

OBJECTIVES

The current recommended treatment for severe fetal anemia is in utero transfusion (IUT). During this procedure, the evaluation of the necessary volume of transfused blood is based on regular measurement of fetal hemoglobin (FHb) concentration. The gold standard measurement is performed in the biology laboratory. A rapid medical test such as HemoCue® is an effective way to predict FHb concentration. It would reduce the time to obtain results and therefore the procedure duration. To evaluate the accuracy of HemoCue® to measure FHb during IUT, we compared Hb levels obtained by HemoCue® and by our biology laboratory.

METHODS

This retrospective study involved all pregnant women who had undergone an IUT in the university hospital of Clermont-Ferrand, France, during the period from 1 January 2010 to 6 June 2021. The FHb level was evaluated by two methods, a rapid medical test, HemoCue®, and a standard method in the biology laboratory.

RESULTS

We obtained 244 pairs of results from HemoCue® and our laboratory, of 90 IUT procedures. The correlation between the two sets of results was excellent, with Lin's concordance correlation coefficient of 0.979. However, we established that the measurements were not significantly modified by IUT number, puncture time, cause of fetal anemia, estimated fetal weight, gestational age, and delay between two IUT or middle cerebral artery peak systolic velocity values.

CONCLUSION

Our results allowed to extend the relevance of FHb measurements by HemoCue® during IUT.

Hemolytic disease of the fetus and newborn: rapid review of postnatal care and outcomes

BACKGROUND

Advances in postnatal care for hemolytic disease of the fetus and newborn (HDFN) have occurred over the past decades, but little is known regarding the frequency of postnatal treatment and the clinical outcomes of affected neonates. Most studies reporting on HDFN originate from high-income countries or relatively large centers, but important differences between centers and countries may exist due to differences in prevalence and available treatment options. We therefore aimed to evaluate the postnatal treatment landscape and clinical outcomes in neonates with Rhesus factor D (Rh(D))- and/or K-mediated HDFN and to provide recommendations for future research.

METHODS

We conducted a rapid literature review of case reports and series, observational retrospective and prospective cohort studies, and trials describing pregnancies or children affected by Rh(D)- or K-mediated HDFN published between 2005 and 2021. Information relevant to the treatment of HDFN and clinical outcomes was extracted. Medline, ClinicalTrials.gov and EMBASE were searched for relevant studies by two independent reviewers through title/abstract and full-text screening. Two independent reviewers extracted data and assessed methodological quality of included studies.

RESULTS

Forty-three studies reporting postnatal data were included. The median frequency of exchange transfusions was 6.0% [interquartile range (IQR): 0.0-20.0] in K-mediated HDFN and 26.5% [IQR: 18.0-42.9] in Rh(D)-mediated HDFN. The median use of simple red blood cell transfusions in K-mediated HDFN was 50.0% [IQR: 25.0-56.0] and 60.0% [IQR: 20.0-72.0] in Rh(D)-mediated HDFN. Large differences in transfusion rates were found between centers. Neonatal mortality amongst cases treated with intrauterine transfusion(s) was 1.2% [IQR: 0-4.4]. Guidelines and thresholds for exchange transfusions and simple RBC transfusions were reported in 50% of studies.

CONCLUSION

Most included studies were from middle- to high-income countries. No studies with a higher level of evidence from centers in low-income countries were available. We noted a shortage and inconsistency in the reporting of relevant data and provide recommendations for future reports. Although large variations between studies was found and information was often missing, analysis showed that the postnatal burden of HDFN, including need for neonatal interventions, remains high.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2021 CRD42021234940. Available from:  https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021234940 .

Double/Triple Intrauterine Blood Transfusion in Rh-isoimmunized Anemic Fetuses in Multiple Pregnancies with Favorable Outcome

Background

Multiple pregnancies have increased with the use of assisted reproduction, and we expect more women reporting with Rh isoimmunization among multiple gestation in near future. Intrauterine transfusion in singleton itself is technically difficult and requires a lot of skill and precision. Performing double/triple transfusion in twins/triplets is expected to be more demanding.

Aim

To create awareness on the technical difficulties encountered in intrauterine transfusion in twins and triplets.

Methodology

We report a case series of four Rh-isoimmunized twins/triplets in 5 years who presented with severe anemia requiring intrauterine transfusion.

Results

Each of the four sets of cases had their own intricacies that needed to be pondered before tackling them as not much was available in the literature. In Case 1, the first twin intrauterine transfusion in our 20-year-long experience, the difficulty in the approach to the first twin due to a posteriorly placed placenta has been highlighted. Case 2 was rare due to the concomitant presence of atypical antibodies in the mother in addition to Rh-D isoimmunization that made it difficult to cross match any donor blood for intrauterine transfusion. The third case was exclusive due to its monochorionic-diamniotic nature of the twins where the impact of inter-twin anastomosis on the transfusion was to be taken into consideration. Fourth case was a triplet gestation where the difficulty of which cord to be assigned to which fetus, the crowded space for intervention, as well as the risk of prolonged operative time and associated risk of preterm/premature rupture of membranes were our concern.

Conclusion

Intrauterine transfusion (IUT) in twins/triplets is challenging. Difficulties encountered during IUT in multifetal gestation are due to different or uncertain chorionicity, intraplacental anastomosis between vessels, different degree of anemia in twins, difficult to ascertain cord-fetus relationship and difficulty to reach placental insertion site due to crowding by multiple fetal parts.

Velocity Time Integral: A Novel Method for Assessing Fetal Anemia

The velocity time integral (VTI) is a clinical Doppler ultrasound measurement of blood flow, measured by the area under the wave curve and equivalent to the distance traveled by the blood. This retrospective study assessed the middle cerebral artery (MCA) VTI of fetuses in pregnancies complicated by maternal alloimmunization. Doppler indices of the MCA were retrieved from electronic medical records. Systolic deceleration-diastolic time, systolic acceleration time, VTI, and peak systolic velocity (PSV) were measured at 16-40 weeks gestation. Cases with PSV indicating fetal anemia (cutoff 1.5 MoM) and normal PSV were compared. The study included 255 Doppler ultrasound examinations. Of these, 41 were at 16-24 weeks (group A), 100 were at 25-32 weeks (group B), and 114 were at 33-40 weeks (group C). VTI increased throughout gestation (5.5 cm, 8.6 cm, and 12.1 cm in groups A, B, and C, respectively, p = 0.003). VTI was higher in waveforms calculated to have MCA-PSV ≥ 1.5 MoM compared to those with MCA-PSV < 1.5 MoM (9.1 cm vs. 14.1 cm, respectively, p < 0.001), as was VTI/s (22.04 cm/s vs. 33.75 cm/s, respectively; p < 0.001). The results indicate that the MCA VTI increases significantly among fetuses with suspected anemia, indicating higher perfusion of hemodiluted blood to the brain. This feasible measurement might provide a novel additional marker for the development of fetal anemia.

History and current standard of postnatal management in hemolytic disease of the fetus and newborn

Since the discovery of the Rh blood group system in 1940, a greater understanding of hemolytic disease of the fetus and newborn (HDFN) was gained. In the years thereafter, researchers and clinicians came to the current understanding that fetal and neonatal red blood cells (RBC) are hemolyzed by maternal alloantibodies directed against RBC antigens potentially leading to severe disease. Preventative measures, such as Rhesus(D) immunoprophylaxis (RhIG), have greatly decreased the prevalence of Rh(D)-mediated HDFN, although a gap between high-income countries and middle- to low-income countries was created largely due to a lack in availability and high costs of RhIG. Other important developments in the past decades have improved the identification, monitoring, and care of pregnancies, fetuses, and neonates with HDFN. Prenatally, fetal anemia may occur and intrauterine transfusions may be needed. Postnatally, pediatricians should be aware of the (antenatally determined) risk of hemolysis in RBC alloimmunization and should provide treatment for hyperbilirubinemia in the early phase and monitor for anemia in the late phase of the disease. Through this review, we aim to provide an overview of important historic events and to provide hands-on guidelines for the delivery and postnatal management of neonates with HDFN. Secondarily, we aim to describe recent scientific findings and evidence gaps.

CONCLUSION

 Multiple developments have improved the identification, monitoring, and care of pregnancies and neonates with HDFN throughout the centuries. Pediatricians should be aware of the (antenatally determined) risk of hemolysis in RBC alloimmunization and should provide treatment for hyperbilirubinemia in the early phase and monitor for late anemia in the late phase of the disease. Future studies should be set in an international setting and ultimately aim to eradicate HDFN on a global scale.

WHAT IS KNOWN

• Developments have led to a greater understanding of the pathophysiology, an improved serological identification and monitoring of at-risk cases and the current pre- and postnatal treatment.

WHAT IS NEW

• This review provides the pediatrician with hands-on guidelines for the delivery and postnatal management of neonates with HDFN. • Future studies should be set in an international setting with the ultimate aim of eradicating HDFN.

Hemolytic disease of the fetus and newborn: systematic literature review of the antenatal landscape

BACKGROUND

Prevention of pregnancy-related alloimmunization and the management of hemolytic disease of the fetus and newborn (HDFN) has significantly improved over the past decades. Considering improvements in HDFN care, the objectives of this systematic literature review were to assess the prenatal treatment landscape and outcomes of Rh(D)- and K-mediated HDFN in mothers and fetuses, to identify the burden of disease, to identify evidence gaps in the literature, and to provide recommendations for future research.

METHODS

We performed a systematic search on MEDLINE, EMBASE and clinicaltrials.gov. Observational studies, trials, modelling studies, systematic reviews of cohort studies, and case reports and series of women and/or their fetus with HDFN caused by Rhesus (Rh)D or Kell alloimmunization. Extracted data included prevalence; treatment patterns; clinical outcomes; treatment efficacy; and mortality.

RESULTS

We identified 2,541 articles. After excluding 2,482 articles and adding 1 article from screening systematic reviews, 60 articles were selected. Most abstracted data were from case reports and case series. Prevalence was 0.047% and 0.006% for Rh(D)- and K-mediated HDFN, respectively. Most commonly reported antenatal treatment was intrauterine transfusion (IUT; median frequency [interquartile range]: 13.0% [7.2-66.0]). Average gestational age at first IUT ranged between 25 and 27 weeks. weeks. This timing is early and carries risks, which were observed in outcomes associated with IUTs. The rate of hydrops fetalis among pregnancies with Rh(D)-mediated HDFN treated with IUT was 14.8% (range, 0-50%) and 39.2% in K-mediated HDFN. Overall mean ± SD fetal mortality rate that was found to be 19.8%±29.4% across 19 studies. Mean gestational age at birth ranged between 34 and 36 weeks.

CONCLUSION

These findings corroborate the rareness of HDFN and frequently needed intrauterine transfusion with inherent risks, and most births occur at a late preterm gestational age. We identified several evidence gaps providing opportunities for future studies.

Intravenous immunoglobulin in the management of severe early onset red blood cell alloimmunisation

Our objective was to assess the effect of maternal intravenous immunoglobulin (IVIG) administration for severe red blood cell (RBC) alloimmunisation on fetal outcomes. This is a case-control study. Women with a history of severe early onset alloimmunisation resulting in fetal loss in a previous pregnancy and high anti-D or anti-K antibody titres received IVIG in a subsequent pregnancy. We assessed gestational age at first transfusion and fetal outcomes in the subsequent pregnancy and compared these with the outcomes in the previous pregnancy. The most responsible antibody was anti-D in 17 women and anti-K in two others, whilst seven had more than one antibody. In all, 19 women received IVIG in 22 pregnancies, two of which did not even need an intrauterine transfusion (IUT). For previous early losses despite transfusion, IVIG was associated with a relative increase in fetal haemoglobin between treated and untreated pregnancies of 36.5 g/L (95% confidence interval 19.8-53.2, p = 0.0013) and improved perinatal survival (eight of eight vs. none of six, p = 0.001). For previous losses at <20 weeks, it enabled first transfusion deferral in subsequent pregnancies to at least 19.9 weeks (mean 23.2 weeks). Overall, IVIG decreases the severity of haemolytic disease of the fetus and newborn and allows deferral of the first IUT to a safer gestation in severe early-onset RBC alloimmunisation and rarely may even avoid the need for IUT entirely.

Identification and management of fetal anemia due to hemolytic disease

INTRODUCTION

Hemolytic disease of the fetus and newborn (HDFN) is a condition caused by maternal alloantibodies against fetal red blood cells (RBCs) that can cause severe morbidity and mortality in the fetus and newborn. Adequate screening programs allow for timely prevention and intervention resulting in significant reduction of the disease over the last decades. Nevertheless, HDFN still occurs and with current treatment having reached an optimum, focus shifts toward noninvasive therapy options.

AREAS COVERED

This review focusses on the timely identification of high risk cases and antenatal management. Furthermore, we elaborate on future perspectives including improvement of screening, identification of high risk cases and promising treatment options.

EXPERT OPINION

In high-income countries mortality and morbidity rates due to HDFN have drastically been reduced over the last decades, yet worldwide anti-D mediated HDFN still accounts for 160,000 perinatal deaths and 100,000 patients with disabilities every year. Much of these deaths and disabilities could have been avoided with proper identification and prophylaxis. By implementing sustainable prevention, screening, and disease treatment measures in all countries this will systemically reduce unnecessary perinatal deaths. There is a common responsibility to engage in this cause.

Practice patterns amongst fetal centers performing intrauterine transfusions (PACT): An international survey study

OBJECTIVES

Fetal anemia secondary to incompatibility between maternal-fetal blood types can result in hydrops and demise. Intrauterine transfusions have improved survival in experience centers. Our objective was to determine the practice patterns amongst fetal centers.

STUDY DESIGN

Thirteen fetal centers across the world were surveyed. Results from all participating centers were recorded, analyzed, and presented as ratios. Questions on the survey were related to experience of the physician, preferred methods of transfusion, fetal surveillance, and timing of delivery.

RESULTS

Differences amongst centers were as follows: 54% of the centers performed transfusions in operating room, the remaining did them in a clinic room or close to the operating room; 31% did not use maternal anesthesia, 31% used oral or intravenous sedation and 38% used a combination of local with oral or intravenous sedation. The similarities include: 84% performed intravenous transfusions, while 2 centers reported intraperitoneal and intracardiac transfusions were performed for very early cases; 85% of centers performed the last transfusion at 34-35 weeks and 77% electively delivered their patients at 37 weeks.

CONCLUSION

Method of transfusion and delivery timing was similar in most centers; however, differences were seen in location of procedure, anesthetic coverage, and surveillance. Further assessment is needed to determine if these differences in practice have any potential neonatal effects.

Polyhydramnios as a sole ultrasonographic finding for detecting fetal hemolytic anemia caused by anti-c alloimmunization

OBJECTIVE

The prenatal course of a rare case with fetal anemia caused by maternal anti-c alloimmunization was reported.

CASE REPORT

A 39-year-old female with anti-c and anti-E antibodies against red cells had previously experienced a stillbirth. At her present pregnancy, titers of maternal antibodies and fetal middle cerebral artery peak systolic velocity (MCA-PSV) were frequently monitored to investigate the severity of fetal hemolytic anemia. Rather than manifesting as an increase in MCA-PSV, the anemic fetus was delivered at 32 weeks and one day of gestation with a sole presentation: polyhydramnios. Neonatal hospitalization course were compatible with hemolytic anemia. The baby was discharged at 48 days of age.

CONCLUSION

This case illustrated the complexities of dealing with maternal red cell alloimmunization during pregnancy and the limitations of noninvasive diagnostic modalities for detecting fetal anemia, and highlighted that obstetricians should refer all available clinical parameters in order to offer appropriate perinatal care.

Extremely Rare Case of Fetal Anemia Due to Mitochondrial Disease Managed with Intrauterine Transfusion

This report describes a rare case of fetal anemia, confirmed as a mitochondrial disease after birth, treated with intrauterine transfusion (IUT). Although mitochondrial diseases have been described in newborns, research on their prenatal features is lacking. A patient was referred to our institution at 32 gestational weeks owing to fetal hydrops. Fetal anemia was confirmed by cordocentesis. After IUT had been performed three times, the anemia and associated fetal hydrops showed improvement. However, after birth, the neonate had recurrent pancytopenia and lactic acidosis. He was eventually diagnosed with Pearson syndrome and died 2 months after birth. This is the first case report of fetal anemia associated with mitochondrial disease managed with IUT.

Pregnancy Outcome of Rh D Alloimmunized Pregnancies: A Tertiary Care Institute Experience of a Developing Country

Aim

To determine the socio-demographic characteristics and pregnancy outcome of Rh D alloimmunized women monitored with MCA PSV (middle cerebral artery peak systolic velocity).

Materials and Methods

In total, 363 Rh D alloimmunized women attended antenatal clinic or obstetric emergency between January 2006 and December 2014. MCA PSV was the screening method for detection of fetal anemia. Intrauterine blood transfusion (IUT) was given when MCA PSV was > 1.5 MOM. Totally, 162 women (164 fetuses) received 492 transfusions. Forty-eight women had fetal hydrops at presentation. Five women (three received IUT) were lost to follow-up. Pregnancy outcome of 358 women and socio-demographic characteristics of 363 women were analyzed.

Results

The perinatal mortality was 421, 66 and 87 per 1000 live births in hydrops group, non-hydrops IUT group and non-IUT group, respectively.

Conclusion

Rh alloimmunization is still a major cause of perinatal morbidity and mortality. The higher gravidity, previous history of pregnancy wastage, still births and hydrops increase the requirement of intrauterine transfusion. MCA PSV is an excellent tool for monitoring of Rh alloimmunized pregnancies to detect fetal anemia. Early detection and monitoring by MCA PSV improve its outcome.

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.

Parvovirus b19 infection in pregnancy - A review

Parvovirus B19 (B19V) is a widespread infection that may affect 1-5% of pregnant women, mainly with normal pregnancy outcome. Vertical transmission occurs in 33-51% of cases of maternal infection. B19V infection is an important cause of fetal morbidity (fetal anaemia and non-immune hydrops) and mortality, predominantly in the second trimester. Diagnosis of B19V infection requires a multi-method approach using mainly serology and PCR techniques. Severe fetal anaemia is managed with intrauterine transfusion with perinatal survival rates following intrauterine transfusion ranging from 67% to 85%. If fetal anaemia is mild, and considering that hydrops can spontaneously resolve, invasive therapy is not recommended and B19V complicated pregnancy may be non-invasively monitored by serial ultrasound examination and MCV-PSV measurements. As an alternative, intrauterine IVIG therapy has been described with successful treatment of fetal hydrops. No specific antiviral therapy or vaccine is presently available for B19V infection but efforts in the search for compounds inhibiting B19V replication are now being pursued. New virus-like-particle based parvovirus B19 vaccine candidates, produced by co-expressing VP2 and either wild-type VP1 or phospholipase-negative VP1 in a regulated ratio from a single plasmid inSaccharomyces cerevisiae have been developed and show sufficient promise to test in humans.

Fetal Hepatomegaly: Causes and Associations

Fetal hepatomegaly is associated with significant fetal morbidity and mortality. However, hepatomegaly might be overlooked when numerous other fetal anomalies are present, or it might not be noticed when it is an isolated entity. As the largest solid organ in the abdomen, the liver can be seen well with US or MRI, and the normal imaging characteristics are well described. The length of the fetal liver, which can be used to identify hepatomegaly, can be determined by measuring the liver from the diaphragm to the tip of the right lobe in the sagittal plane. Fetal hepatomegaly is seen with infection, transient abnormal myelopoiesis, liver storage and deposition diseases, some syndromes, large liver tumors, biliary atresia, and anemia. Some of these diagnoses are treatable during the fetal period. Attention to the associated findings and specific hepatic and nonhepatic imaging characteristics can help facilitate more accurate diagnoses and appropriate patient counseling.^©RSNA, 2020.

Optimization of diagnostic strategy for non-invasive cell-free foetal RHD determination from maternal plasma

BACKGROUND AND OBJECTIVES

The aim of the study was to optimize routine non-invasive prenatal detection of fetal RHD gene from plasma of RhD-negative pregnant women (the median of gestational age was 25 weeks, range 10-38) to detect RhD materno-fetal incompatibility and to avoid the redundant immunoprophylaxis.

MATERIALS AND METHODS

Initially only one exon of RHD gene (exon 10) was investigated in 281 plasma samples (144 verified after delivery), in the second phase three RHD exons (5, 7, 10) were analyzed in 246 samples of plasma and maternal genomic DNA (204 verified) by real-time PCR method. Detection of Y-chromosomal sequence DYS-14 and five X-chromosomal insertion/deletion polymorphisms was used to confirm the fetal cfDNA detectability in plasma. Specific polymorphisms in RHD gene were detected by sequence-specific primer PCR in nine samples.

RESULTS

When only the RHD exon 10 was tested, 2·8% of verified samples were false positive and 3·5% false negative. With three RHD exons (5, 7, 10) and maternal genomic DNA testing, only one case was false negative (0·5%). Nine samples were inconclusive due to RHD-positive results in maternal genomic DNA. These samples were analyzed for specific mutations in RHD gene. Combination of both methods for fetal cfDNA verification succeeded in 75% of tested group.

CONCLUSION

Implementation of analysis of three RHD exons and maternal genomic DNA to routine practice lowers dramatically the ratio of false positive and negative results. This method enables more accurate determination of fetal RHD status with the reduction of unnecessary medical care and RhD immunoprophylaxis.

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 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.

Medical therapy to attenuate fetal anaemia in severe maternal red cell alloimmunisation

Haemolytic disease of the fetus and newborn (HDFN) remains an important cause of fetal mortality with potential neonatal and longer-term morbidity. HDFN is caused by maternal red cell alloimmunisation, with IgG antibodies crossing the placenta to destroy fetal erythroid cells expressing the involved antigen. Intrauterine fetal blood transfusion is the therapy of choice for severe fetal anaemia. Despite a strong evidence base and technical advances, invasive fetal therapy carries risk of miscarriage and preterm birth. Procedure-related risks are increased when invasive, in utero transfusion is instituted prior to 22 weeks to treat severe early-onset fetal anaemia. This review focuses upon this cohort of HDFN and discusses intravenous immunoglobin (IVIg) and novel monoclonal antibody (M281, nipocalimab) treatments which, if started at the end of the first trimester, may attenuate the transplacental passage and fetal effects of IgG antibodies. Such therapy has the ability to improve fetal survival in this severe presentation of HDFN when early in utero transfusion may be required and may have wider implications for the perinatal management in general.

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.

Red cell alloimmunization: A 2020 update

Management of maternal red cell alloimmunization has been revolutionized over the last 60 years. Advances in the prevention, screening, diagnosis, and treatment of alloimmune-induced fetal anemia make this condition an exemplar for contemporary practice in fetal therapy. Since survival is now an expectation, attention has turned to optimization of long-term outcomes following an alloimmunized pregnancy. In this review, the current management of red cell alloimmunization is described. Current research and future directions are discussed with particular emphasis on later life outcomes after alloimmune fetal anemia.

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.

Evaluation of Rh-Hemolytic Disease in Neonates and Management with Early Intensive Phototherapy in the Neonatal Intensive Care Unit

BACKGROUND OF THE STUDY

In neonates with Rh-hemolytic disease, light emitting diode (LED) phototherapy allows delivery of high spectral irradiance (SI). A linear correlation exists between SI and efficacy of phototherapy with no saturation point. There is scant data on evaluation and early phototherapy using LED units in Rh-hemolytic disease.

OBJECTIVE

This study aimed to describe the hemoglobin (Hb), hematocrit (Hct), total serum bilirubin (TSB), phototherapy parameters and short-term outcomes in neonates with Rh-hemolytic disease.

METHODOLOGY

Maternal parameters for Rh-isoimmunization were recorded and monitoring of fetal anemia by Doppler ultrasound was done. Early intensive phototherapy within 1 h of birth was initiated for cord blood Hb below 13.6 g/dl and/or TSB greater than 2.8 mg/dl.

RESULTS

Fifty Rh positive neonates were enrolled of which 11/50 (22%) received intrauterine transfusions. The maximum TSB remained below 18 mg/dl in 42/50 (84%) of neonates. The mean SI on the trunk was 56.260 ± 8.768 µW/cm2/nm and duration of phototherapy was 7 ± 3.29 days (mean ± SD). There was a positive correlation between strength of indirect antiglobulin test and cord blood Hb: correlation coefficient (r) = 0.295; direct antiglobulin test and duration of phototherapy: r = 0.331. Early packed red blood cell (PRBC) transfusion was required in 8/50 (16%) neonates while 20/50 (40%) required late transfusions.

CONCLUSION

With a mean SI of 56.260 ± 8.768 µW/cm2/nm on the trunk, TSB remained below 18 mg/dl in majority thereby avoiding exchange transfusion. Early or late PRBC transfusion requirement was 1 (1-2) (median ± interquartile range).

Knowledge, attitude and practices of obstetric care providers towards maternal red-blood-cell immunization during pregnancy

Background and objectives

A successful routine RBC alloantibody screening programme should not lead to unnecessary emotional burden during pregnancy due to inadequate counselling on the risk of severe haemolytic disease of the foetus and the newborn (HDFN). Rareness of this disease may result in insufficient knowledge and subsequent inadequate information transfer to women, diagnosed with RBC antibodies. We investigated the current knowledge, views and experiences of Dutch obstetric care providers regarding RBC alloimmunization during pregnancy.

Materials and methods

We performed a quantitative cross‐sectional study, using a structured digital questionnaire to measure knowledge, attitude and practices (KAP) regarding maternal RBC alloimmunization among Dutch obstetric care providers in 2016.

Results

About 10% of obstetric care providers completed the questionnaire. A sufficient level of knowledge was found in 7% of all participants (N = 329). Knowledge about RhD immunisation and prophylaxis was sufficient in 60% of the responders. Knowledge gaps were found concerning the relevance of non‐RhD RBC antibodies, the indications for giving extra RhD prophylaxis and the interpretation of laboratory test results. Healthcare providers estimated their own level of knowledge ‘sufficient’ (primary/secondary care) to ‘good’ (tertiary care), and all participants considered their professional role important within the screening programme.

Conclusion

Dutch obstetric care providers showed a lack of knowledge regarding maternal RBC immunization. Awareness of the lack of knowledge is necessary to help obstetric care providers to be careful in giving information and even to decide to contact the expert centre before counselling the patient.

Diagnostic value of laboratory monitoring to predict severe hemolytic disease of the fetus and newborn in non-D and non-K-alloimmunized pregnancies

BACKGROUND

Pregnant women are routinely screened for red blood cell (RBC) antibodies early in pregnancy. If RBC-alloantibodies are detected, repeated laboratory testing is advised to timely identify pregnancies at high risk for severe hemolytic disease of the fetus and newborn (HDFN). We assessed for RBC alloantibodies, other than anti-D or anti-K, cut-offs for the titer and the antibody dependent cellular cytotoxicity (ADCC) test to select high-risk cases. To advise on test repeat intervals, and to avoid unnecessary testing, we evaluated the chance for exceeding the cut-offs for Rh antibodies other than anti-D, Jk, Fy, and S/s antibodies.

STUDY DESIGN AND METHODS

Diagnostic value of antibody titer and ADCC test was determined with data from a prospective index-cohort study, conducted in 2002-2004. Laboratory test outcomes were from a recent observational cohort (2015-2016).

RESULTS

A titer cut-off of ≥16 showed a sensitivity of 100% (95% CI:73-100%) and a positive predictive value (PPV) of 17% (95% CI:14%-20%). The percentage of pregnancies reaching a titer above the cut-off of ≥16 varied from 0% for anti-Jk^a /Jk^b (n = 38) to 36% for anti-c (n = 97). The ADCC test showed no cut-off with a 100% sensitivity. However, in cases with a titer ≥16 and an ADCC test ≥30% a PPV of 38% was obtained to detect severe HDFN.

CONCLUSION

A titer cut-off of ≥16 is adequate to detect all cases at risk for severe HDFN; the ADCC test may add a more accurate risk estimation. Repeated testing is recommended in pregnancies with anti-c. In pregnancies with other Rh antibodies a repeated test in the third trimester is recommended.

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.

Management and outcome of pregnancies in women with red cell isoimmunization: a 15-year observational study from a tertiary care university hospital

BACKGROUND

The aims of this study were to determine the prevalence of the different anti-erythrocytic alloantibodies, to describe pregnancy outcomes according to a low-risk and high-risk classification for fetal anemia and to determine the factors that influence adverse perinatal outcomes.

METHODS

This retrospective observational study included women referred to our center following the identification of maternal anti-erythrocytic alloantibodies between 2002 and 2017. Pregnancies were classified as high risk for fetal anemia in cases with clinically significant antibodies, no fetal-maternal compatibility and titers ≥1:16 or any titration in cases of Kell system incompatibility. In high-risk pregnancies, maternal antibody titration and the fetal middle cerebral artery peak systolic velocity (MCA-PSV) were monitored. Low-risk pregnancies underwent routine pregnancy follow-up.

RESULTS

Maternal antibodies were found in 337 pregnancies, and 259 (76.9%) of these antibodies were clinically significant. The most frequent antibodies were anti-D (53%) and anti-K (19%). One hundred forty-three pregnancies were classified as low risk for fetal anemia, 65 (25%) cases were classified as no fetal-maternal incompatibility, 78 had clinically nonsignificant antibodies, 4 (2.8%) resulted in first-trimester pregnancy loss, and 139 (97.2%) resulted in livebirths. Of the 194 high-risk pregnancies, 38 had titers < 1:16 (resulting in 38 livebirths), and 156 had titers ≥1:16 or anti-K antibodies. In the last group, 6 cases miscarried before 18 weeks, 93 had a MCA-PSV < 1.5 multiples of the median (MoM), resulting in 3 perinatal deaths that were unrelated to fetal anemia, one termination and 89 livebirths; and 57 had a MCA-PSV > 1.5 MoM, resulting in 3 intrauterine deaths, 6 terminations and 48 livebirths. Ninety-two intrauterine transfusions were performed in 45 fetuses (87% anti-D). Adverse outcomes were related to a MCA-PSV > 1.5 MoM (p < 0.001), hydrops (p < 0.001) and early gestational age at first transfusion (p = 0.029) CONCLUSION: Anti-D remains the most common antibody in fetuses requiring intrauterine transfusion. A low or high-risk classification for fetal anemia based on the type of antibody, paternal phenotype and fetal antigen allows follow-up of the pregnancy accordingly, with good perinatal outcomes in the low-risk group. In the high-risk group, adverse perinatal outcomes are related to high MCA-PSV, hydrops and early gestational age at first transfusion.

Dispelling Myths about Antenatal TAPS: A Call for Action for Routine MCA-PSV Doppler Screening in the United States

In the United States, routine middle cerebral artery peak systolic velocity (MCA-PSV) Doppler screening for the detection of antenatal twin anemia-polycythemia sequence (TAPS) is not recommended. The current and only national clinical guideline from the highly-influential Society for Maternal-Fetal Medicine states that, “There is no evidence that monitoring for TAPS with MCA PSV Doppler at any time, including > 26 weeks, improves outcomes, so that this additional screening cannot be recommended at this time.” We argue this recommendation has disproportionate influence on patients and the care they are offered and receive. We use current evidence to highlight and dispel pervasive myths surrounding antenatal TAPS and the value of routine MCA-PSV screening. An ethical framework that illustrates the importance of giving patients the opportunity for routine screening is presented. Findings demonstrate that: (1) both spontaneous and post-laser TAPS is a serious, potentially life-threatening complication, (2) treatment for TAPS is effective and includes expectant management, intrauterine transfusion (IUT), or surgery, (3) and routine MCA-PSV, which has satisfactory diagnostic accuracy, is currently the only way to provide early detection of TAPS. We conclude that routine TAPS screening is a medically proven valuable resource that should be offered to patients in need and to the clinicians who are trying to act toward their benefit.

Short-Term Flow Changes in Monochorionic Survivor Twins after Ultrasound-Guided Umbilical Cord Occlusion

OBJECTIVE

To determine hemodynamic changes by Doppler ultrasound of the living fetus during 24 h after umbilical cord occlusion (UCO) in monochorionic diamniotic (MCDA) twin pregnancies.

METHOD

We conducted a prospective observational study on fetuses undergoing UCO from 2015 to 2017. Doppler parameters peak systolic velocity (PSV) and umbilical pulsatility index (PI) were obtained in the middle cerebral artery (MCA), umbilical artery (UA) and ductus venosus (DV) before and right after UCO, and at 1, 3, 6, 12, and 24 h after. We used multiple of the median (MoM) to adjust for gestational age. Spaghetti plots visualized flow changes over time. Mixed model adjusting for paired longitudinal data compared the values at different time points.

RESULTS

A total of 16 women were included. MCA-PSV dropped within the first hour after surgery from 0.91 to 0.82 MoM (p = 0.08). MCA-PI and UA-PI increased in the first hour from 0.75 to 0.91 MoM (p = 0.02) and 0.94 to 0.98 MoM (p = 0.22), respectively. The DV-PIV increased to 1.14 MoM 3 h after surgery (p = 0.07). The spaghetti plots illustrated the small changes within the first hours and showed a stabilization of flow measurements near initial values 24 h after UCO.

CONCLUSION

Within the first hours after UCO the circulation of the survivor twin undergoes small hemodynamic changes.

Magnetic Resonance Imaging: A New Tool to Optimize the Prediction of Fetal Anemia?

INTRODUCTION

The false-positive rate in the prediction of fetal anemia is 10-15%. We investigated if a new, noninvasive MRI method used as a supplement to ultrasound could improve the prediction.

METHODS

Fetuses suspected of anemia and controls were scanned in a 1.5-tesla MRI scanner 1-4 times during pregnancy. Cases were scanned before and after intrauterine blood transfusion with a T1-mapping MRI sequence in a cross-section of the umbilical vein.

RESULTS

Inclusion of 8 cases and 11 controls resulted in 10 case scans (2 cases were included twice) and 33 control scans. In controls, the T1 relaxation time was 1,005-1,391 ms; in cases with severe anemia, 1,505-1,595 ms, moderate anemia 1,503-1,525 ms, and no/mild anemia 1,245-1,410 ms. After blood transfusions, values dropped to 1,123-1,288 ms. The mean value in moderate and severe anemic cases was 275 ms higher than in controls (95% CI 210-341 ms, p < 0.0001), and after blood transfusion it was comparable to controls (3 ms, 95% CI -62 to 68 ms, p = 0.934). A 1,450-ms cut-off would have identified all cases in need of blood transfusion with no false-positive cases.

CONCLUSIONS

Our findings indicate a potential for this new MRI method to improve the prediction of fetal anemia as a supplement to ultrasound.

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.

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.

Anti-D quantification in relation to anti-D titre, middle cerebral artery Doppler measurement and clinical outcome in RhD-immunized pregnancies

BACKGROUND

The optimal strategy to monitor RhD-immunized pregnancies is not evident. Whether a quantitative analysis of anti-D antibodies adds valuable information to anti-D titre is unclear. The aim of this study was to evaluate the relevance of anti-D quantification in routine monitoring of RhD-immunized pregnancies.

MATERIALS AND METHODS

In a retrospective study, 64 consecutive pregnancies in 61 immunized women with anti-D titre ≥128 at any time during pregnancy were included. According to routine, at titre ≥128, anti-D quantification was performed by flow cytometry and the peak systolic velocity in the middle cerebral artery was measured by ultrasound. Decisions for treatment with intrauterine blood transfusion were based on increased peak systolic velocity in the middle cerebral artery.

RESULTS

Increasing anti-D concentrations correlated well to increasing anti-D titres, but at each titre value, there was a large interindividual variation, in the determined anti-D concentration. Intrauterine transfusions were initiated in 35 pregnancies according to algorithms based on ultrasound measurements, at anti-D concentrations of 2·4-619 IU/ml and titre 128-16 000. Sixty pregnancies resulted in a live-born child, three in miscarriage and one in termination of pregnancy. During the perinatal care in the neonatal intensive care unit, thirty-one of the neonates were treated with blood exchange transfusions and/or red cell transfusions and 47 were treated with phototherapy.

CONCLUSION

Anti-D quantification does not add further information compared to anti-D titre, in defining a critical level to start monitoring RhD-immunized pregnancies with Doppler ultrasound.

Predicting anti-Kell-mediated hemolytic disease of the fetus and newborn: diagnostic accuracy of laboratory management

BACKGROUND

There is controversy on critical cut-off values of laboratory testing to select pregnancies at increased risk for anti-Kell-mediated hemolytic disease of the fetus and newborn. Without early detection and treatment, anti-Kell-mediated hemolytic disease of the fetus and newborn may result in progressive fetal anemia, fetal hydrops, asphyxia, and perinatal death.

OBJECTIVE

We aimed to determine the value of repeated anti-Kell titer determination and biological activity measurement using the antibody-dependent cellular cytotoxicity test determination in the management of pregnancies at risk for anti-Kell-mediated hemolytic disease of the fetus and newborn.

STUDY DESIGN

This was a retrospective cohort study of pregnancies with anti-Kell and a Kell-positive fetus, identified from January 1999 through April 2015. Laboratory test results and clinical outcome were collected from the Dutch nationwide screening program and the national reference center for fetal therapy in The Netherlands, the Leiden University Medical Center. Diagnostic accuracy was measured (receiver operating characteristic curves, sensitivity, specificity, positive and negative predictive values) for anti-Kell titers and antibody-dependent cellular cytotoxicity test. The relationship between the titer and antibody-dependent cellular cytotoxicity measurements and the 2 foregoing measurements were computed with a Pearson product-moment correlation coefficient.

RESULTS

In a 16-year unselected cohort, representing screening results of 3.2 million pregnancies resulting in live births in The Netherlands, we identified 1026 Kell-immunized pregnancies. In all, 93 pregnant women had anti-Kell and a Kell-positive child, without other red cell alloantibodies. In all, 49 children (53%) needed intrauterine or postnatal transfusion therapy. The first anti-Kell titer showed already a high diagnostic accuracy with an area under the curve of 91%. The optimal cut-off point for the titer was 4 (sensitivity 100%; 95% confidence interval, 91-100), specificity 27% (95% confidence interval, 15-43), and positive predictive value 60% (49-71%). The antibody-dependent cellular cytotoxicity test was not informative to select high-risk pregnancies. Linear regression showed no significant change during pregnancy, when antibody titer and antibody-dependent cellular cytotoxicity test results were compared with every 2 foregoing measurements (P < .0001).

CONCLUSION

Early determination of the anti-Kell titer is sufficient to select pregnancies at increased risk for hemolytic disease of the fetus and newborn with need for transfusion therapy. If the Kell status of the fetus is known to be positive, a titer of ≥4 can be used to target intensive clinical monitoring.

The near disappearance of fetal hydrops in relation to current state-of-the-art management of red cell alloimmunization

Objective

In this study, we aim to evaluate trends in the condition of fetuses and neonates with hemolytic disease at the time of first intrauterine transfusion (IUT) and at birth, in relation to routine first‐trimester antibody screening, referral guidelines, and centralization of fetal therapy.

Method

We conducted a 30‐year cohort study including all women and fetuses treated with IUT for red cell alloimmunization at the Dutch national referral center for fetal therapy.

Results

Six hundred forty‐five fetuses received 1852 transfusions between 1 January 1987 and 31 December 2016. After the introduction of routine first‐trimester antibody screening, the hydrops rate declined from 39% to 15% (OR 0.284, 95% CI, 0.19‐0.42, P < 0.001). In the last time cohort, only one fetus presented with severe hydrops (OR 0.482, 95% CI, 0.38‐0.62, P < 0.001). Infants are born less often <32 weeks (OR 0.572, 95% CI, 0.39‐0.83, P = 0.004) and with higher neonatal hemoglobin (P < 0.001). Neonatal hemoglobin was positively independently associated with gestational age at birth, fetal hemoglobin, and additional intraperitoneal transfusion at last IUT.

Conclusion

Severe alloimmune hydrops, a formerly often lethal condition, has practically disappeared, most likely as a result of the introduction of routine early alloantibody screening, use of national guidelines, and pooling of expertise in national reference laboratories and a referral center for fetal therapy.

What's already known about this topic?

Severe alloimmune hydrops is associated with impaired outcome on both the short term and the long term.

What does this study add?

With routine early alloantibody screening, national guidelines, and pooling of expertise in national reference laboratories and a referral center for fetal therapy, severe alloimmune hydrops has almost disappeared.

Survival of hydrops cases no longer differs from hemolytic disease of the fetus and newborn cases without hydrops.

Children treated with intrauterine transfusions are now in better condition at birth.

Unexpected middle cerebral artery peak systolic velocity values in the normal fetal population. Are they a matter of concern?

Objective: The aim of this study was to investigate in the fetus the relationship between unexpected high middle cerebral artery peak systolic velocity (middle cerebral artery (MCA) peak systolic velocity (PSV)) values and hemoglobin (Hgb) levels in normal pregnancies without conditions leading to fetal anemia.Material and methods: This was a prospective study of 922 singleton low-risk pregnant women attending the maternity of La Fe Hospital between 35 and 41 weeks. Multiple pregnancies and pregnancies with growth restriction, smallness, macrosomia or conditions leading to fetal anemia were excluded. During each examination, a biometry and a Doppler examination of the umbilical artery pulsatility index (umbilical artery (UA) pulsatility index (PI)), MCA PI and MCA PSV were performed. MCA PSV was converted into multiples of median (MoM), and birth weight (BW) into centiles adjusting for gender. All pregnancies delivered in a 2-week interval since examination. In order to explain Hgb levels at birth, a correlation between MCA PSV MoM and Hgb was performed and Hgb levels of fetuses with normal MCA PSV and abnormal MCA PSV were compared, using 1.3 MoM as cut-off for mild anemia. Finally, a multivariate linear regression analysis was performed including MCA PSV MoM and several Doppler and clinical parameters.Results: The univariate analysis showed no correlation between the MCA PSV MoM and the umbilical artery Hgb (r² = 0.026, p = .1237) while a weak correlation was found with the umbilical vein Hgb (r² = 0.0053, p = .027). Also, fetuses with values of MCA PSV MoM <1.3 MoM did not differ in terms of artery and vein Hgb with those presenting values >1.3 MoM (p = .99 and p = .61, respectively). Finally, both prediction models explaining arterial and venous Hgb presented very weak predictive accuracies (R Squared: 0.0965 and R Squared: 0.106) indicating a low possibility to diagnose fetal anemia in otherwise normal fetuses based on clinical and sonographic data.Conclusion: In normal pregnancies that are not suffering from conditions leading to fetal anemia, unexpected high MCA PSV values do not necessarily reflect the presence of this condition. Active management in this circumstance might result in unjustified higher rates of labor induction and operative delivery.

Red Blood Cell Alloimmunization in the Pregnant Patient

Alloimmunization to red blood cell (RBC) antigens represents a challenge for physicians caring for women of child bearing potential. Exposure to non-self RBC antigens may occur during transfusion or pregnancy leading to the development of antibodies. If a subsequent fetus bears that antigen, maternal antibodies may attack the fetal red blood cells causing red cell destruction and clinically significant hemolytic disease of the fetus and newborn (HDFN). In the most severe cases, HDFN may result in intrauterine fetal demise due to high output cardiac failure, effusions and ascites, known as "hydrops fetalis". This article reviews strategies for management and prevention of RBC alloimmunization in women of child bearing potential.