Fetal anemia

Prenatal parvovirus B19 infection

Parvovirus B19 (B19V) causes erythema infectiosum, a.k.a., fifth disease. This disease primarily affects children. It is generally self-limiting and subsides after 1-2 weeks. In pregnancy, the virus can cross the placenta and result in a fetal infection. This may lead to severe fetal anemia, hydrops fetalis, a miscarriage, or intrauterine fetal death. The risk of long-term sequelae also appears to be increased. About one-third of pregnant women are not immune to B19V and, therefore, are at risk to contract a primary infection. The seroconversion rate during pregnancy is generally around 1-2%. During a primary infection, maternal-fetal transplacental transmission of B19V occurs in about 30-50% of the cases and the risk of fetal infection increases with advancing gestational age. The risk of severe fetal anemia or hydrops is around 3-4% overall and is around 6-7% if the primary infection occurs before 20 weeks' gestation. Fetal monitoring in women with a primary B19V infection includes regular ultrasound examinations looking for evidence of hydrops fetalis and Doppler measurements of the middle cerebral artery peak velocity. Fetal blood sampling is performed if a significant anemia is suspected and, if such is found, an intrauterine blood transfusion is needed. This article provides an overview of the epidemiology, pathogenesis, clinical manifestations, diagnostic methods, and management of B19V infection during pregnancy.

Maternal isoimmunization associated fetal anemia: A case report

Maternal isoimmunization occurs when a pregnant woman develops an immune reaction due to the inheritance of a red-cell antigen, which is paternally derived and can result in fetal anemia, hemolysis, fetal death, and hydrops fetalis as the antibodies might travel through the placenta and get adhered to the antigens present in the erythrocytes of the fetus. This report highlights a rare case of Rh isoimmunization leading to fetal anemia in a 26-year-old female and evaluates the impact of intrauterine transfusion (IUT) in terms of the gestational age at delivery along with the mode of delivery, procedural complications, and overall survival rate of the fetus. In conclusion, the most frequent cause of fetal anemia is Rh alloimmunization, which should be taken into consideration while making a differential diagnosis throughout the assessment. Improvements in IUT procedures and earlier detection of the MCA-PSV by Doppler ultrasonographic examination have also contributed to better results.

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.

Fetal hemodynamic changes and mitochondrial dysfunction in myocardium and brain tissues in response to anemia: a lesson from hemoglobin Bart's disease

OBJECTIVE

Whether or not the effects of anemia in the early phase, while the fetuses attempts to increase cardiac output to meet oxygen requirement in peripheral organs, is detrimental to the fetal developing vital organs is little-known. The objective of this is to compare prenatal cardiovascular changes and post-abortal cellular damages in the myocardium as a pumping organ and the brain as a perfused organ between anemic fetuses (using fetal Hb Bart's disease as a study model) in pre-hydropic phase and non-anemic fetuses.

METHODS

Fetuses affected by Hb Bart's disease and non-anemic fetuses at 16-22 weeks were recruited to undergo comprehensive fetal echocardiography. Cord blood analysis was used to confirm the definite diagnosis of fetal Hb Bart's disease and normal fetuses. Fetal cardiac and brain tissues were collected shortly after pregnancy termination for the determination of oxidative stress and mitochondrial function, including mitochondrial ROS production and mitochondrial membrane changes.

RESULTS

A total of 18 fetuses affected by Hb Bart's disease and 13 non-anemic fetuses were recruited. The clinical characteristics of both groups were comparable. The affected fetuses showed a significant increase in cardiac dimensions, cardiac function, cardiac output and brain circulation without deteriorating cardiac contractility and preload. However, in the affected fetuses, mitochondrial dysfunction was clearly demonstrated in brain tissues and in the myocardium, as indicated by a significant increase in the membrane potential change (p-value < 0.001), and a significant increase in ROS production in brain tissues, with a trend to increase in myocardium. The findings indicated cellular damage in spite of good clinical compensation.

CONCLUSION

The new insight is that, in response to fetal anemia, fetal heart increases in size (dilatation) and function to increase cardiac output and blood flow velocity to provide adequate tissue perfusion, especially brain circulation. However, the myocardium and brain showed a significant increase in mitochondrial dysfunction, suggesting cellular damage secondary to anemic hypoxia. The compensatory increase in circulation could not completely prevent subtle brain and heart damage.

( G γ A γ δ β ) 0 $({}^{\rm G}{\gamma}{}^{\rm A}{\gamma}\delta\beta)^0$ -Thalassemia: Report of two cases in a family

Case 1 presented with severe anemia and received an intrauterine blood cell transfusion at 33 weeks of gestation. The anemia spontaneously improved in early infancy. Case 2, the father of Case 1, had an uneventful birth with no evidence of anemia, though microcytic anemia was observed during childhood. The genetic analysis of the β-globin gene cluster identified a novel heterozygous deletion of DNA extending from the Gγ-globin gene downstream to the β-globin gene, confirming a diagnosis of (G γA γδβ)0 -thalassemia. In cases where thalassemia is suspected based on blood tests, a genetic diagnosis should be performed for the sake of the offspring.

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.

Abnormal heart rate pattern in fetal anaemia secondary to transient abnormal myelopoeisis in a fetus without trisomy 21: A case report

Decreased fetal movements (DFM) are a non-specific and common symptom in the third trimester of pregnancy that hold an association with fetal compromise. A 28-year-old woman at 31 weeks and 3 days of gestation presented with DFM and was found to have a pathological fetal heart rate trace. Following emergency Caesarean section the fetus was diagnosed with transient abnormal myelopoeisis (TAM). Timely treatment was initiated and the neonatal outcome was good. Transient myeloproliferative disorders are almost uniquely found in infants with trisomy 21 (T21). This is the first case report of TAM in the absence of T21 wherein the diagnostic process was commenced antenatally due to non-reassuring fetal status and highlights the importance of antenatal heart rate abnormalities.

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.

Prenatal Diagnosis of Congenital Lymphocytic Choriomeningitis Virus Infection: A Case Report

Lymphocytic choriomeningitis virus (LCMV) is an emerging neuroteratogen which can infect humans via contact with urine, feces, saliva, or blood of infected rodents. When the infection occurs during pregnancy, there is a risk of transplacental infection with subsequent neurological or visual impairment in the fetus. In this article, we describe a case report of congenital LCMV infection, including fetal imaging, confirmed by positive LCMV IgM in fetal blood and cerebrospinal fluid.

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.

Massive fetomaternal hemorrhage: a case series and review of literature

Objectives

Massive fetomaternal hemorrhage (FMH) is a rare and difficult to diagnose event that can have catastrophic outcomes. Although many etiologies have been associated with FMH, the majority of cases are idiopathic and affect uncomplicated pregnancies. The prevailing symptom is decreased fetal movements but some cases are asymptomatic. Changes in the fetal Doppler ultrasound, a sinusoidal cardiotocographic pattern, neonatal anemia, unexplained hydrops or stillbirth can raise suspicion that such an event has occurred.

Case presentation

This article presents a case series of severe FMH diagnosed in our center between 2011 and 2020 as well as a review of the current available literature.

Conclusions

We highlight the importance of the clinician’s awareness on detecting this rare but potentially life-threatening event.

Parvovirus (B19) Infection during Pregnancy: Possible Effect on the Course of Pregnancy and Rare Fetal Outcomes. A Case Report and Literature Review

Infection caused by human parvovirus B19 (B19) often has mild yet wide-ranging clinical signs, with the course of disease usually defined as benign. Particularly prevalent in the population of young children, the virus is commonly transmitted to the parents, especially to susceptible mothers. During pregnancy, particularly the first and second trimesters, parvovirus infection can lead to pathology of the fetus: anemia, heart failure, hydrops, and disorders of physical and neurological development. In severe cases, the disease can result in fetal demise. This article presents a rare case of manifestation of B19 infection during pregnancy. At the 27th week of gestation, a sudden change in fetal movement occurred in a previously healthy pregnancy. The examination of both fetus and the mother revealed newly formed fetal subdural hematoma of unknown etiology and ventriculomegaly. Following extensive examination to ascertain the origin of fetal pathology, a maternal B19 infection was detected. Due to worsening fetal condition, a planned cesarean section was performed to terminate the pregnancy at 31 weeks of gestation. A preterm male newborn was delivered in a critical condition with congenital B19 infection, hydrocephalus, and severe progressive encephalopathy. The manifestation and the origin of the fetal condition remain partially unclear. The transplacental transmission of maternal B19 infection to the fetus occurs in approximately 30% of cases. The main method for diagnosing B19 infection is Polymerase Chain Reaction (PCR) performed on blood serum. In the absence of clinical manifestations, the early diagnosis of B19 infection is rarely achieved. As a result, the disease left untreated can progress inconspicuously and cause serious complications. Treatment strategies are limited and depend on the condition of the pregnant woman and the fetus. When applicable, intrauterine blood transfusion reduces the risk of fetal mortality. It is crucial to assess the predisposing factors of the infection and evaluate signs of early manifestation, as this may help prevent the progression and poor outcomes of the disease.

Development of a training model for teaching intrauterine fetal blood transfusion

This article describes an inexpensive simulator developed for teaching intrauterine blood transfusion. The model is constructed from a boneless chicken thigh folded over a Penrose drain placed in a water-filled snap-lock lid container and covered by melted ballistic gel to simulate the fetal intrahepatic vessel. Participants valued this educational tool and reported feeling the model was practical and realistic. This low-cost, high-fidelity model provides realistic tissue resistance and represents a sonographically accurate intrahepatic fetal blood transfusion training tool.

Outcome predictors for maternal red blood cell alloimmunisation with anti-K and anti-D managed with intrauterine blood transfusion

Red blood cell (RBC) alloimmunisation with anti-D and anti-K comprise the majority of cases of fetal haemolytic disease requiring intrauterine red cell transfusion (IUT). Few studies have investigated which haematological parameters can predict adverse fetal or neonatal outcomes. The aim of the present study was to identify predictors of adverse outcome, including preterm birth, intrauterine fetal demise (IUFD), neonatal death (NND) and/or neonatal transfusion. We reviewed the records of all pregnancies alloimmunised with anti-K and anti-D, requiring IUT over 27 years at a quaternary fetal centre. We reviewed data for 128 pregnancies in 116 women undergoing 425 IUTs. The median gestational age (GA) at first IUT was significantly earlier for anti-K than for anti-D (24·3 vs. 28·7 weeks, P = 0·004). Women with anti-K required more IUTs than women with anti-D (3·84 vs. 3·12 mean IUTs, P = 0·036) and the fetal haemoglobin (Hb) at first IUT was significantly lower (51.0 vs. 70.5 g/l, P = 0·001). The mean estimated daily decrease in Hb did not differ between the two groups. A greater number of IUTs and a slower daily decrease in Hb (g/l/day) between first and second IUTs were predictive of a longer period in utero. Earlier GA at first IUT and a shorter interval from the first IUT until delivery predicted IUFD/NND. Earlier GA and lower Hb at first IUT significantly predicted need for phototherapy and/or blood product use in the neonate. In the anti-K group, a greater number of IUTs was required in women with a higher titre. Furthermore, the higher the titre, the earlier the GA at which an IUT was required in both groups. The rate of fall in fetal Hb between IUTs decreased, as the number of transfusions increased. Our present study identified pregnancies at considerable risk of an unfavourable outcome with anti-D and anti-K RBC alloimmunisation. Identifying such patients can guide pregnancy management, facilitates patient counselling, and can optimise resource use. Prospective studies can also incorporate these characteristics, in addition to laboratory markers, to further identify and improve the outcomes of these pregnancies.

Comparison of the Performances of Middle Cerebral Artery Peak Systolic Velocity and Cardiothoracic Diameter Ratio in Predicting Fetal Anemia: Using Fetal Hemoglobin Bart's Disease as a Study Model

OBJECTIVE

The aim of the study was to compare the performances of cardiothoracic diameter ratio (CTR) and middle cerebral artery peak systolic velocity (MCA-PSV) in predicting fetal hemoglobin (Hb) Bart's disease and identify the best CTR cut-off for each gestational period.

METHODS

Pregnancies at risk of fetal Hb Bart's disease (gestational ages of 12-36 weeks) were prospectively recruited to undergo ultrasound examination. The measurements of CTR and MCA-PSV were performed and recorded before invasive diagnosis.

RESULTS

During the study period (2005-2019), a total of 1,717 pregnancies at risk of fetal Hb Bart's disease met the inclusion criteria and were available for analysis, including 329 (19.2%) fetuses with Hb Bart's disease. The mean gestational age at the time of diagnosis was 19.30 ± 5.6 weeks, ranging from 12 to 36 weeks. The overall performance of CTR Z-scores is superior to that of MCA-PSV multiple of median (MoM) values; area under curve of 0.866 versus 0.711, p value <0.001. The diagnostic indices of CTR and MCA-PSV are increased with gestational age. Based on receiver operating characteristic curves of CTR Z-scores, the best cut-off points of CTR at 12-14, 15-17, 18-20, 21-23, and ≥24 weeks are 0.48, 0.49, 0.50, 0.51, and 0.54, respectively. The best cut-off of MCA-PSV is 1.3 MoM, giving the best performance at 21-23 weeks with a sensitivity of 91.8% and specificity of 85.5%.

CONCLUSION

The performance of CTR is much better than MCA-PSV in predicting fetal anemia caused by Hb Bart's disease. Nevertheless, whether this can be reproduced in anemia due to other causes, like isoimmunization, is yet to be explored.

Performance of Fetal Cardiac Volume Derived from VOCAL (Virtual Organ Computer-Aided AnaLysis) in Predicting Hemoglobin (Hb) Bart's Disease

OBJECTIVE

To determine the performance of fetal cardiac volume (CV) in the detection of fetal Hb Bart's disease among fetuses at risk at 18-22 weeks of gestation and to compare the performance with those of cardiothoracic diameter ratio (CTR) and middle cerebral artery peak systolic velocity (MCA-PSV).

METHODS

Fetuses at risk of Hb Bart's disease between 18 and 22 weeks of gestation prospectively underwent echocardiography with acquisition of the volume datasets (VDS) of fetal heart, using 4D-cardiac STIC. Subsequently, off-line analysis was blindly performed to measure cardiac volume using the VOCAL technique.

RESULTS

A total of 502 fetuses at risk meeting the inclusion criteria were included in the analysis, consisting of 117 (23.3%) fetuses with Hb Bart's disease and 385 (76.7%) unaffected fetuses. The mean (±SD) gestational age at the time of ultrasound examination was 19.70 ± 1.3 weeks. In predicting fetal Hb Bart's disease, CV, using a cut-off Z-score of 1.7, had a sensitivity of 94.9% and specificity of 94.0%. The performance of CV was slightly better than that of CTR but very superior to that of MCA-PSV (areas under curve: 0.988, 0.974 and 0.862, respectively).

CONCLUSIONS

Fetal CV has a very high performance in predicting fetal Hb Bart's disease at mid-pregnancy, comparable with CTR and much better than MCA-PSV.

Severe fetal anemia and hydrops fetalis associated with compound heterozygosity for Hb Zurich-Albisrieden (HBA2:c.178G>C) and Hb Quong Sze (HBA2:c.377T>C)

We report on a fetus with cardiomegaly and increased middle cerebral artery-peak systolic velocity at 25 weeks of gestation. Severe fetal anemia (hemoglobin (Hb) level 37 g/L) was confirmed by cordocentesis. Hb analysis showed that Hb Bart’s was 9% in cord blood. Molecular analysis of the proband’s family found that the mother was a carrier of Hb Quong Sze (Hb QS, HBA2:c.377T>C), the father was a carrier of Hb Zurich-Albisrieden (Hb ZA, HBA2:c.178G>C), and the fetus was a compound heterozygote for Hb ZA and Hb QA. Despite intrauterine blood transfusions, the fetus experienced problems including oligohydramnios, growth retardation, placental thickening, and heart enlargement in the third trimester. The couple chose to terminate the pregnancy, and fetal autopsy confirmed the above diagnosis. This is the first report of a case of Hb ZA compounded with Hb QS, and provides a reference for genetic counselling and prenatal diagnosis in the Chinese population.

Perinatal outcomes and survival predictors of severe red-cell alloimmunization treated by intrauterine transfusion

OBJECTIVE

To evaluate perinatal survival rates and predictors in severely anemic fetuses that underwent intrauterine transfusion (IUT).

METHOD

This was a retrospective study of both Turkish and Syrian patients who underwent IUT for fetal anemia due to Rh alloimmunization between 2015 and 2019. The association between pretransfusion factors and perinatal survival was evaluated by multivariate logistic regression. Receiver operating characteristics (ROC) curves were used to identify the level of fetal hemoglobin deficits that predict perinatal survival.

RESULTS

Eighty-seven IUTs were performed in 42 pregnancies. Approximately 75% of fetuses were severely anemic and the overall perinatal survival rate was 50%. The survival rate was better in Syrian refugees compared to Turkish patients (71.4% vs. 39.3%, p < 0.05). In univariate analysis, hydrops presence (odds ratio [OR] = 0.2; 95% confidence interval [CI] = 0.05-0.7; p < 0.05), first IUT week (OR = 1.4; 95% CI = 1.1-1.8; p < 0.05), pretransfusion hemoglobin level (OR = 1.99; 95% CI = 1.22-3.27; p < 0.05), hemoglobin deficit (OR = 0.5; 95% CI = 0.3-0.8; p < 0.05), and birth week (OR = 2.3; 95% CI = 1.3-3.9; p < 0.05) were associated with survival. However in a multivariate analysis, only hemoglobin deficit (OR = 0.47; 95% CI = 0.22-0.99; p < 0.05) and birth week (OR = 3.3; 95% CI = 1.1-10.3; p < 0.05) were found to be associated with survival. On ROC analysis, a hemoglobin deficit of ≤6.25 g/dl showed a sensitivity of 0.95 and specificity of 0.62 for predicting perinatal survival.

CONCLUSION

Despite the improvement in the treatment of fetal anemia, perinatal survival rate remains extremely low in severely anemic cases. Among pretransfusion factors, hemoglobin deficit seemed to be most important in predicting survival during fetal anemia.

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.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Severe fetal anemia as a consequence of extra-abdominal umbilical vein varix: A case report and review of the literature

Umbilical vein varix is associated with a high incidence of fetal anomalies and perinatal complications. There are two types of umbilical vein varix: fetal intra-abdominal and extra-abdominal. Herein, a case is reported of severe fetal anemia with extra-abdominal umbilical vein varix. A 33-year-old primigravida was referred to our hospital for fetal growth restriction, fetal cardiomegaly, and decreased fetal movements at 26 weeks' gestation. A Doppler assessment showed an elevated middle cerebral artery peak systolic velocity at 2.2 MoM, suggesting fetal anemia. Umbilical vein varix had caused intermittent turbulent flow, provoking hemolytic anemia. Intrauterine transfusion improved fetal circulatory failure and anemia and prolonged gestational period. At 33 weeks' gestation, the patient underwent cesarean delivery due to nonreassuring fetal status. Pathological analysis revealed focal loss of vascular smooth muscle of the umbilical vein. Extra-abdominal umbilical vein varix has been reported in 14 cases including this case. The antenatal diagnosis rate is reported to be 79%; fetal heartbeat abnormalities and fetal deaths were reported as 50% and 14%, respectively. Eighty-six percent of patients had intra-umbilical cord thrombosis, but currently this is the only case of hemolytic anemia. Furthermore, extra-abdominal umbilical vein varix may present as fetal hydrops with anemia. During ultrasound examination of fetal anemia, umbilical cord screening should be performed with caution.

Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations

Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.

Ionizable lipid nanoparticles for in utero mRNA delivery

Clinical advances enable the prenatal diagnosis of genetic diseases that are candidates for gene and enzyme therapies such as messenger RNA (mRNA)-mediated protein replacement. Prenatal mRNA therapies can treat disease before the onset of irreversible pathology with high therapeutic efficacy and safety due to the small fetal size, immature immune system, and abundance of progenitor cells. However, the development of nonviral platforms for prenatal delivery is nascent. We developed a library of ionizable lipid nanoparticles (LNPs) for in utero mRNA delivery to mouse fetuses. We screened LNPs for luciferase mRNA delivery and identified formulations that accumulate within fetal livers, lungs, and intestines with higher efficiency and safety compared to benchmark delivery systems, DLin-MC3-DMA and jetPEI. We demonstrate that LNPs can deliver mRNAs to induce hepatic production of therapeutic secreted proteins. These LNPs may provide a platform for in utero mRNA delivery for protein replacement and gene editing.

Performance of the Kleihauer Betke test in the prediction of neonatal anemia

OBJECTIVES

The aim of this study was to correlate antenatal Kleihauer (KT) test results with fetal hemoglobin at birth to find a threshold for predicting severe fetal anemia. The secondary objectives were to assess the impact of KT on obstetric management and to study the correlation between the middle cerebral artery peack systolic velocity and fetal anemia.

RESULTS

One thousand forty-six KT were positive over the 10-year period, but only 147 were included from 88 patients, of which 17 fetuses were anemic. Demographic and obstetric characteristics were similar between anemic and non-anemic groups. As regards new-born, there was a higher risk of prematurity among anemic as long as a lower birth rate in accordance. While a negative correlation was observed between KT and hemoglobin at birth, no KT upper threshold could be found that was both sensitive and specific. In addition, there was no case of fetal anemia when KT was repeated, even though it increased. KT showed little usefulness in obstetrics management to help improving neonatal care for anemia. Conversely, the MCA PSV demonstrated good performance in this matter and the ROC curve area was 0.91 (figure).

DISCUSSION

Feto-maternal hemorrhage is a rare but grave pathology which could lead to anemia. The most common clinical sign is reduced fetal movement and it was the main indication to perform a KT. Cardiotocography patterns suggestive of anemia are sinusoidal, micro-oscillatory and non-reactive monitoring. Ultrasound features were polyhydramnios, hydrop fetalis and increased MCA peack systolic velocity. KT was correlated with MCA PSV and with hemoglobin level at birth. However, the latter showed a better diagnostic performance. MCA PSV measurement is a powerful test to screen for fetal anemia, and should be part of the regular training of obstetricians. Indeed, this technic gives immediate and reliable results, while those of KT are delayed.

CONCLUSION

The KT should not be used as a tool to screen for fetal anemia but rather as a test to explain a fetal anemia. However, the MCA PSV is reliable in this matter and give immediate result, thus obstetrician should be trained to routinely perform it.

Foetal haemodynamic response to anaemia

This study aims to update new knowledge regarding foetal cardiovascular response to anaemia, using foetal haemoglobin Bart's disease as a study model. Original research articles, review articles, and guidelines were narratively reviewed and comprehensively validated. The main foetal cardiovascular changes in response to anaemia are consequences of hypervolaemia and increased cardiac output to meet tissue oxygen requirement. New challenging insights are as follows: (i) the earliest morphological change is an increase in cardiac size and remodelling of the sphericity (an increase in diameter more pronounced than that in long axis) followed by several markers, such as placentomegaly and hepatosplenomegaly. (ii) The earliest functional change is increased peak systolic velocity of the red blood cells because of low viscosity, especially in the middle cerebral artery. (iii) The foetal heart has very high reserve potentials to cope with anaemia: increasing workload without increased central venous pressure and increased myocardial performance without compromising shortening fraction. This hard‐working period with good performance lasts long, including most part of the second and third trimester. (iv) At the time cardiomegaly myocardial cellular damage has already occurred, in spite of good cardiac function. (v) Anaemic hydrops foetalis is mainly due to hypervolaemia, hypoalbuminaemia, and high vascular permeability, not heart failure. (vi) Foetal heart failure occurs only when the adaptive mechanism becomes exhausted or long after the development of anaemic hydrops foetalis. Heart failure is a very late result of a longstanding overworked heart. (vii) Ultrasound is highly effective in the detection of foetal response to anaemia. An increase in cardiac size and middle cerebral artery is very helpful in predicting the affected foetuses in pre‐hydropic phase. (viii) Theoretically, intrauterine treatment of anaemic hydrops results in satisfactory outcomes as long as cardiac function is normal, but intrauterine intervention should be strongly considered in pre‐hydropic phase because myocardial cell damage could have already occurred in this phase or early hydropic phase. Anaemic hydrops foetalis is not primarily caused by heart failure as commonly advocated, but it is rather a consequence of hypervolaemia, hypoalbuminaemia, and high vascular permeability while heart failure is a very late consequence of a longstanding overworked heart. New insights gained from this review may be useful to base clinical practice on which sonographic markers imply significant pathological changes, how ultrasound can be helpful in early detection of anaemic response, when intrauterine transfusion for anaemia due to non‐lethal causes should be administered, etc.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Fetal Physiologically Based Pharmacokinetic Models: Systems Information on Fetal Blood Components and Binding Proteins

BACKGROUND

Fetal blood and plasma volume and binding components are critical parameters in a fetal physiologically based pharmacokinetic model. To date, a comprehensive review of their changes during fetal development has not been reported.

OBJECTIVE

The objective of this work was to collate and analyze physiological information on fetal blood and plasma volume and binding component data during development and to provide a mathematical description of these parameters that can be integrated within a fetal physiologically based pharmacokinetic model.

METHODS

A comprehensive literature search was conducted on fetal blood and plasma volume and binding component parameters and their changes during growth from apparently healthy fetuses from uncomplicated pregnancies. Collated data were assessed, integrated, and analyzed to establish continuous mathematical functions describing their growth trends with fetal age and weight.

RESULTS

Data were available from 14 studies for blood, ten studies for hematocrit, 12 studies for albumin, and four studies for alpha-1-acid glycoprotein, while plasma and red blood cell volumes were described based on blood and hematocrit data. Fetal physiologically based pharmacokinetic parameters, including blood, plasma and red blood cell volumes, hematocrit, serum albumin, and acid glycoprotein were quantified as a function of fetal age and weight. Variability around the mean parameters at different fetal ages was also investigated. The growth of each of these parameters was different (with respect to direction and monotonicity).

CONCLUSIONS

Despite the limitations identified in the availability of some values, the collected data presented in this article provide a useful resource for fetal physiologically based pharmacokinetic modeling. Potential applications include predicting xenobiotic exposure and risk assessment in the fetus following maternally administered drugs or unintended exposure to environmental toxicants.

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.

Successful Management of the Fetal Severe Anemia Associated with Jra Alloimmunization by Intrauterine Transfusion of Jr(a+) Red Blood Cells

Objective

We present a case of fetal severe anemia associated with Jra alloimmunization, which was managed using Doppler measurement of the peak systolic velocity of the fetal middle cerebral artery (MCA-PSV) and intrauterine transfusion (IUT) of Jr(a+) red blood cells (RBCs). We also review the previous case reports on fetal or neonatal anemia associated with Jra alloimmunization.

Case Report

A woman with Jra alloimmunization was referred to our department at 29 weeks of gestation. As fetal MCA-PSV exceeded 1.55 multiples of the median, fetal blood sampling was performed and demonstrated severe anemia. During the course, a total of two IUTs were performed using Jr(a+) RBCs. The neonate was delivered by repeated cesarean section at 35 weeks of gestation and showed no apparent signs of hemolysis.

Conclusion

Based on the literature review, fetal anemia associated with Jra alloimmunization becomes severe during mid-gestation and may not develop during late gestation. The severity of fetal anemia is predicted by MCA-PSV Doppler assessment rather than the maternal anti-Jra titers. Timely IUT of Jr(a+) RBCs can help to prolong the pregnancy to term in emergency situations wherein compatible blood of Jr(a-) RBCs is not available soon.

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.

The best cutoff value of middle cerebral artery peak systolic velocity for the diagnosis of fetal homozygous alpha thalassemia-1 disease

OBJECTIVE

To determine the best cutoff value of middle cerebral artery peak systolic velocity (MCA-PSV) for the diagnosis of fetuses with homozygous alpha thalassemia-1 disease.

METHODS

Pregnancies at risk for fetal homozygous alpha thalassemia-1 disease at 18 to 22 weeks were recruited. MCA-PSV was measured before cordocentesis for hemoglobin typing and complete blood count. The performance of the MCA-PSV for identifying affected fetuses was evaluated using a best cutoff value derived from the receiver operating characteristic (ROC) curve.

RESULTS

Among 142 fetuses at risk, 46 (32.4%) fetuses were diagnosed as affected by homozygous alpha thalassemia-1 disease and were categorized as mild anemia (16.3%), moderate anemia (58.1%), and severe anemia (25.6%). With the best cutoff point of MCA-PSV > 1.30 multiples of the median (MoM) or >30.0 cm/s, the sensitivity for predicting fetal homozygous alpha thalassemia-1 was 100%.

CONCLUSIONS

MCA-PSV > 1.30 MoM is the best cutoff value for the diagnosis of all degrees of fetal anemia from homozygous alpha thalassemia-1 fetuses. Because of its simplicity for interpretation and high efficacy, a cutoff value of MCA-PSV > 30 cm/s can also be used as an alternative marker for fetal anemia screening during 18 to 22 weeks of gestation.

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.

Pregnancy complications and adverse outcomes in placental chorioangioma: a retrospective cohort analysis

Objective: To measure the relative risk of pregnancy complications and adverse outcomes in women with placental chorioangioma, and postnatal developmental deficiencies in their offspring.Methods: We designed a retrospective cohort study using records from 140,387 pregnancies at our hospital between 1 January, 2008 and 1 July, 2017. Follow-up of children in the placental chorioangioma group was conducted by phone interview.Results: Placental chorioangioma was diagnosed in 56 patients (incidence = 0.04%). Fifty-one cases were detected during routine prenatal ultrasound. Placental chorioangioma patients were at increased risk for fetal loss or induced abortion (RR = 9.93, 95% CI [4.66, 21.20]), preterm birth (n = 13, RR = 2.45, 95% CI [1.52, 3.95]), birth by cesarean section (n = 45, RR = 1.62, 95% CI [1.42, 1.84]), and polyhydramnios (n = 9, RR = 9.98, 95% CI [5.48, 18.18]), but not fetal distress (n = 5, RR = 0.49, 95% CI [0.22, 1.15]) or preeclampsia (n = 5, RR = 1.61, 95% CI [0.70, 3.73]), although there was an increased risk for preeclampsia after controlling for preterm birth (n = 3, RR = 3.6, 95% CI [1.33, 9.74]). No developmental complications were reported in offspring.Conclusion: Placental chorioangioma increases the risk of fetal demise, pregnancy complications and adverse outcomes. In cases with mild complications or when early cesarean termination of pregnancy is feasible, the prognosis is excellent.

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.

Postponing Early intrauterine Transfusion with Intravenous immunoglobulin Treatment; the PETIT study on severe hemolytic disease of the fetus and newborn

BACKGROUND

Intrauterine transfusion for severe alloimmunization in pregnancy performed <20 weeks' gestation is associated with a higher fetal death rate. Intravenous immunoglobulins may prevent hemolysis and could therefore be a noninvasive alternative for early transfusions.

OBJECTIVE

We evaluated whether maternal treatment with intravenous immunoglobulins defers the development of severe fetal anemia and its consequences in a retrospective cohort to which 12 fetal therapy centers contributed.

STUDY DESIGN

We included consecutive pregnancies of alloimmunized women with a history of severe hemolytic disease and by propensity analysis compared index pregnancies treated with intravenous immunoglobulins (n = 24) with pregnancies managed without intravenous immunoglobulins (n = 28).

RESULTS

In index pregnancies with intravenous immunoglobulin treatment, fetal anemia developed on average 15 days later compared to previous pregnancies (8% less often <20 weeks' gestation). In pregnancies without intravenous immunoglobulin treatment anemia developed 9 days earlier compared to previous pregnancies (10% more <20 weeks), an adjusted 4-day between-group difference in favor of the immunoglobulin group (95% confidence interval, -10 to +18; P = .564). In the subcohort in which immunoglobulin treatment was started <13 weeks, anemia developed 25 days later and 31% less <20 weeks' gestation (54% compared to 23%) than in the previous pregnancy. Fetal hydrops occurred in 4% of immunoglobulin-treated pregnancies and in 24% of those without intravenous immunoglobulin treatment (odds ratio, 0.03; 95% confidence interval, 0-0.5; P = .011). Exchange transfusions were given to 9% of neonates born from pregnancies with and in 37% without immunoglobulin treatment (odds ratio, 0.1; 95% confidence interval, 0-0.5; P = .009).

CONCLUSION

Intravenous immunoglobulin treatment in mothers pregnant with a fetus at risk for hemolytic disease seems to have a potential clinically relevant, beneficial effect on the course and severity of the disease. Confirmation in a multicenter randomized trial is needed.