Fetal anemia: Diagnosis and management

Prenatal Management and Perinatal Outcome in a Large Series of Hydrops Fetalis

INTRODUCTION

Nonimmune hydrops fetalis (NIHF) is the most frequent etiology of hydrops fetalis (HF), accounting for around 95% of cases. It associates high perinatal mortality and morbidity rates. The aim of the study was, first, to investigate etiology, prenatal management, and perinatal outcome in a large single-center series of HF; second, to identify prenatal prognostic factors with impact on perinatal outcome.

MATERIALS AND METHODS

Observational retrospective study of 80 HF diagnosed or referred to a single tertiary center between 2012 and 2021. Clinical characteristics, etiology, prenatal management, and perinatal outcome were recorded. Adverse perinatal outcome was defined as intrauterine fetal death (IUFD), early neonatal death (first 7 days of life) and late neonatal death (between 7 and 28 days).

RESULTS

Seventy-six of the 80 cases (95%) were NIHF, main etiology being genetic disorders (28/76; 36.8%). A total of 26 women (32.5%) opted for termination of pregnancy, all of them in the NIHF group. IUFD occurred in 24 of 54 patients (44.4%) who decided to continue the pregnancy. Intrauterine treatment was performed in 29 cases (53.7%). There were 30 newborns (55.6%). Adverse perinatal outcome rate was 53.7% (29/54), significantly higher in those diagnosed <20 weeks of gestation (82.4% < 20 weeks vs. 40.5% ≥ 20 weeks; p = 0.004). Survival rate was higher when fetal therapy was performed compared to the expectantly managed group (58.6% vs. 32%; p = 0.05). Intrauterine blood transfusion and thoraco-amniotic shunt were the procedures that achieved the highest survival rates (88.9% and 100%, respectively, p = 0.003).

CONCLUSION

NIHF represented 95% of HF with genetic disorders as the main etiology. Most of them were diagnosed before 20 weeks of gestation, with worse prognosis than cases detected later in gestation. Rates of TOP, IUFD, and early neonatal death were higher in NIHF. Intrauterine therapy, when indicated, improved the perinatal outcome.

Middle cerebral artery peak systolic velocity monitoring of fetal anemia during chemotherapy in pregnancy

INTRODUCTION

Chemotherapy during pregnancy can increase the risk of fetal anemia. Severe fetal anemia can lead to the development of hydrops fetalis and potentially fetal demise. Hence, it is imperative to implement consistent monitoring methods in the context of chemotherapy treatment. This study aimed to diagnose and monitor fetal anemia using middle cerebral artery peak systolic velocity (MCA-PSV) as a diagnostic tool during chemotherapy in pregnant women.

MATERIAL AND METHODS

The study employed a prospective analysis involving a case series of 15 patients diagnosed with cancer during pregnancy and subsequently underwent chemotherapy. MCA-PSV was used to identify fetal anemia. The patients were scheduled for ultrasound examinations of the MCA-PSV. The first examination was performed on the same day as the administration of chemotherapy, while the second occurred on the 10th day after chemotherapy. The measurement technique used in the study was based on the methodology proposed by Mari and Barr. The multiples of the median were calculated using the calculators provided by Medicina Fetal Barcelona. Based on these values anemia severity was determined. When moderate or severe anemia was identified, chemotherapy was individually modified. Additionally, a blood count analysis was conducted immediately after the delivery of the newborn.

RESULTS

Five patients were diagnosed with fetal or newborn anemia. With MCA-PSV, we identified moderate fetal anemia in two patients and severe fetal anemia in one. The complete blood count testing of newborns revealed mild anemia in three patients. One case was unrelated to chemotherapy-induced anemia. During treatment, fetal anemia did not corelate with maternal anemia.

CONCLUSIONS

In four cases of anemia the combination of cisplatin and iphosphamide was used as a chemotherapy agent. No anemia was observed in other drug combinations. Our findings suggest that MCA-PSV is a reliable method for identifying anemia and should be included in the treatment protocol for chemotherapy-induced fetal anemia.

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.

Fetal gene therapy

Fetal gene therapy was first proposed toward the end of the 1990s when the field of gene therapy was, to quote the Gartner hype cycle, at its "peak of inflated expectations." Gene therapy was still an immature field but over the ensuing decade, it matured and is now a clinical and market reality. The trajectory of treatment for several genetic diseases is toward earlier intervention. The ability, capacity, and the will to diagnose genetic disease early-in utero-improves day by day. A confluence of clinical trials now signposts a trajectory toward fetal gene therapy. In this review, we recount the history of fetal gene therapy in the context of the broader field, discuss advances in fetal surgery and diagnosis, and explore the full ambit of preclinical gene therapy for inherited metabolic disease.

How do we perform intrauterine transfusions?

BACKGROUND

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

STUDY DESIGN AND METHODS

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

RESULTS

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

DISCUSSION

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

Non-invasive detection of anemia using lip mucosa images transfer learning convolutional neural networks

Anemia is defined as a drop in the number of erythrocytes or hemoglobin concentration below normal levels in healthy people. The increase in paleness of the skin might vary based on the color of the skin, although there is currently no quantifiable measurement. The pallor of the skin is best visible in locations where the cuticle is thin, such as the interior of the mouth, lips, or conjunctiva. This work focuses on anemia-related pallors and their relationship to blood count values and artificial intelligence. In this study, a deep learning approach using transfer learning and Convolutional Neural Networks (CNN) was implemented in which VGG16, Xception, MobileNet, and ResNet50 architectures, were pre-trained to predict anemia using lip mucous images. A total of 138 volunteers (100 women and 38 men) participated in the work to develop the dataset that contains two image classes: healthy and anemic. Image processing was first performed on a single frame with only the mouth area visible, data argumentation was preformed, and then CNN models were applied to classify the dataset lip images. Statistical metrics were employed to discriminate the performance of the models in terms of Accuracy, Precision, Recal, and F1 Score. Among the CNN algorithms used, Xception was found to categorize the lip images with 99.28% accuracy, providing the best results. The other CNN architectures had accuracies of 96.38% for MobileNet, 95.65% for ResNet %, and 92.39% for VGG16. Our findings show that anemia may be diagnosed using deep learning approaches from a single lip image. This data set will be enhanced in the future to allow for real-time classification.

Anemia detection through non-invasive analysis of lip mucosa images

This paper aims to detect anemia using images of the lip mucosa, where the skin tissue is thin, and to confirm the feasibility of detecting anemia noninvasively and in the home environment using machine learning (ML). Data were collected from 138 patients, including 100 women and 38 men. Six ML algorithms: artificial neural network (ANN), decision tree (DT), k-nearest neighbors (KNN), logistic regression (LR), naive bayes (NB), and support vector machine (SVM) which are widely used in medical applications, were used to classify the collected data. Two different data types were obtained from participants' images (RGB red color values and HSV saturation values) as features, with age, sex, and hemoglobin levels utilized to perform classification. The ML algorithm was used to analyze and classify images of the lip mucosa quickly and accurately, potentially increasing the efficiency of anemia screening programs. The accuracy, precision, recall, and F-measure were evaluated to assess how well ML models performed in predicting anemia. The results showed that NB reported the highest accuracy (96%) among the other ML models used. DT, KNN and ANN reported an accuracies of (93%), while LR and SVM had an accuracy of (79%) and (75%) receptively. This research suggests that employing ML approaches to identify anemia will help classify the diagnosis, which will then help to create efficient preventive measures. Compared to blood tests, this noninvasive procedure is more practical and accessible to patients. Furthermore, ML algorithms may be created and trained to assess lip mucosa photos at a minimal cost, making it an affordable screening method in regions with a shortage of healthcare resources.

Obstetric vascular Doppler velocimetry: clinical applications and overuses

A safe and non-intrusive assessment of fetal health is not only crucial in low-risk gestations, but it is also the standard of care in high-risk pregnancies. Therefore, measuring blood flow across different vessels with non-invasive ultrasound methods has been accurately and painstakingly studied and published. Amongst these state-of-the-art techniques, umbilical artery (blood flow) Doppler velocimetry (UADV) has allowed for fetal well-being follow-ups and assess uteroplacental function, which obtains a more complete and clearer picture; particularly in regard to complicated pregnancies. Additionally, there are other modalities with diverse clinical applications that have emerged, including their clinical and research utilization in conditions such as fetal growth restriction (FGR), preeclampsia, fetal anemia, monochorionic twins vascular blood flow mismatch such as is in twin-to-twin transfusion syndrome, twin anemia polycythemia sequence, and twin reverse arterial perfusion sequence. Nevertheless, their applications regarding various other maternal-fetal diagnoses in the same way as premature births and/or multiple gestation surveillance have not been reported to hold strong clinical evidence. With that in regard, the purpose of this unique study was to give update of the multiple clinical applications of this very important obstetrical tool. Additionally, to review the pathophysiology as well as revisit their reported significant valid uses and occasional overuses. We also delved into quality control measures as related to the application of Doppler in obstetrics. Lastly, it is essential to look through and reflect on the future developments of this valuable, non-invasive, high-risk marvelous modern device.

[Clinical Efficacy and Nursing Care of Fetal Intrauterine Blood Transfusion: Previous Experience Review]

Objective

To summarize the clinical efficacy and nursing experience of intrauterine blood transfusion (IUT) treatment for fetal anemia cases.

Methods

The clinical data of 4 fetal anemia cases receiving IUT in Beijing Obstetrics and Gynecology Hospital, Capital Medical University between 2020 and 2022 were collected. Four pregnant women aged 24-38 years were included in the study. They carried fetuses with anemia of unknown causes. The four pregnant women developed anxiety after they were informed of the diagnosis of fetal anemia. One-on-one psychological counseling before the IUT procedure and one-on-one companionship over the course of the surgery were provided for the pregnant women. In addition, they were closely monitored for blood transfusion reactions. Postprocedural observation of the puncture site and 24-hour monitoring of the newborns were also conducted.

Results

The four pregnant women underwent 1-3 times of IUT in the second and third trimesters, with the minimum gestational age at the time of IUT being 25 + weeks and the blood transfusion volume being 20-107 mL/time. Two pregnant women experienced irregular uterine contractions during IUT in the third trimester. Other than that, all other IUT treatments were successful. After IUT, there was a significant improvement in fetal hemoglobin, peak systolic velocity of the middle cerebral artery (MCA-PSV), and cardiothoracic area ratio. One case did not give birth in our hospital and the outcome of the fetus was not known. The other three fetuses achieved good outcomes.

Conclusion

Positive preprocedural psychological counseling for pregnant women, close intraoprocedural and postprocedural pregnancy monitoring, and the prevention of maternal and fetal complications are the key to improving the clinical efficacy of IUT and achieving a good fetal outcome.

A New Artificial Intelligence Approach Using Extreme Learning Machine as the Potentially Effective Model to Predict and Analyze the Diagnosis of Anemia

The procedure to diagnose anemia is time-consuming and resource-intensive due to the existence of a multitude of symptoms that can be felt physically or seen visually. Anemia also has several forms, which can be distinguished based on several characteristics. It is possible to diagnose anemia through a quick, affordable, and easily accessible laboratory test known as the complete blood count (CBC), but the method cannot directly identify different kinds of anemia. Therefore, further tests are required to establish a gold standard for the type of anemia in a patient. These tests are uncommon in settings that offer healthcare on a smaller scale because they require expensive equipment. Moreover, it is also difficult to discern between beta thalassemia trait (BTT), iron deficiency anemia (IDA), hemoglobin E (HbE), and combination anemias despite the presence of multiple red blood cell (RBC) formulas and indices with differing optimal cutoff values. This is due to the existence of several varieties of anemia in individuals, making it difficult to distinguish between BTT, IDA, HbE, and combinations. Therefore, a more precise and automated prediction model is proposed to distinguish these four types to accelerate the identification process for doctors. Historical data were retrieved from the Laboratory of the Department of Clinical Pathology and Laboratory Medicine, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia for this purpose. Furthermore, the model was developed using the algorithm for the extreme learning machine (ELM). This was followed by the measurement of the performance using the confusion matrix and 190 data representing the four classes, and the results showed 99.21% accuracy, 98.44% sensitivity, 99.30% precision, and an F1 score of 98.84%.

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.

Prenatal Somatic Cell Gene Therapies: Charting a Path Toward Clinical Applications (Proceedings of the CERSI-FDA Meeting)

We are living in a golden age of medicine in which the availability of prenatal diagnosis, fetal therapy, and gene therapy/editing make it theoretically possible to repair almost any defect in the genetic code. Furthermore, the ability to diagnose genetic disorders before birth and the presence of established surgical techniques enable these therapies to be delivered safely to the fetus. Prenatal therapies are generally used in the second or early third trimester for severe, life-threatening disorders for which there is a clear rationale for intervening before birth. While there has been promising work for prenatal gene therapy in preclinical models, the path to a clinical prenatal gene therapy approach is complex. We recently held a conference with the University of California, San Francisco-Stanford Center of Excellence in Regulatory Science and Innovation, researchers, patient advocates, regulatory (members of the Food and Drug Administration), and other stakeholders to review the scientific background and rationale for prenatal somatic cell gene therapy for severe monogenic diseases and initiate a dialogue toward a safe regulatory path for phase 1 clinical trials. This review represents a summary of the considerations and discussions from these conversations.

Fetal nuchal edema and developmental anomalies caused by gene mutations in mice

Fetal nuchal edema, a subcutaneous accumulation of extracellular fluid in the fetal neck, is detected as increased nuchal translucency (NT) by ultrasonography in the first trimester of pregnancy. It has been demonstrated that increased NT is associated with chromosomal anomalies and genetic syndromes accompanied with fetal malformations such as defective lymphatic vascular development, cardiac anomalies, anemia, and a wide range of other fetal anomalies. However, in many clinical cases of increased NT, causative genes, pathogenesis and prognosis have not been elucidated in humans. On the other hand, a large number of gene mutations have been reported to induce fetal nuchal edema in mouse models. Here, we review the relationship between the gene mutants causing fetal nuchal edema with defective lymphatic vascular development, cardiac anomalies, anemia and blood vascular endothelial barrier anomalies in mice. Moreover, we discuss how studies using gene mutant mouse models will be useful in developing diagnostic method and predicting prognosis.

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.

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.

COVID-19 in Pregnancy and Early Childhood (COPE): study protocol for a prospective, multicentre biobank, survey and database cohort study

INTRODUCTION

There is limited knowledge on how the SARS-CoV-2 affects pregnancy outcomes. Studies investigating the impact of COVID-19 in early pregnancy are scarce and information on long-term follow-up is lacking.The purpose of this project is to study the impact of COVID-19 on pregnancy outcomes and long-term maternal and child health by: (1) establishing a database and biobank from pregnant women with COVID-19 and presumably non-infected women and their infants and (2) examining how women and their partners experience pregnancy, childbirth and early parenthood in the COVID-19 pandemic.

METHODS AND ANALYSIS

This is a national, multicentre, prospective cohort study involving 27 Swedish maternity units accounting for over 86 000 deliveries/year. Pregnant women are included when they: (1) test positive for SARS-CoV-2 (COVID-19 group) or (2) are non-infected and seek healthcare at one of their routine antenatal visits (screening group). Blood, as well as other biological samples, are collected at different time points during and after pregnancy. Child health up to 4 years of age and parent experience of pregnancy, delivery, early parenthood, healthcare and society in general will be examined using web-based questionnaires based on validated instruments. Short- and long-term health outcomes will be collected from Swedish health registers and the parents' experiences will be studied by performing qualitative interviews.

ETHICS AND DISSEMINATION

Confidentiality aspects such as data encryption and storage comply with the General Data Protection Regulation and with ethical committee requirements. This study has been granted national ethical approval by the Swedish Ethical Review Authority (dnr 2020-02189 and amendments 2020-02848, 2020-05016, 2020-06696 and 2021-00870) and national biobank approval by the Biobank Väst (dnr B2000526:970). Results from the project will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04433364.

Anemic hypoxemia reduces myoblast proliferation and muscle growth in late-gestation fetal sheep

Fetal skeletal muscle growth requires myoblast proliferation, differentiation, and fusion into myofibers in addition to protein accretion for fiber hypertrophy. Oxygen is an important regulator of this process. Therefore, we hypothesized that fetal anemic hypoxemia would inhibit skeletal muscle growth. Studies were performed in late-gestation fetal sheep that were bled to anemic and therefore hypoxemic conditions beginning at ∼125 days of gestation (term = 148 days) for 9 ± 0 days (n = 19) and compared with control fetuses (n = 16). A metabolic study was performed on gestational day ∼134 to measure fetal protein kinetic rates. Myoblast proliferation and myofiber area were determined in biceps femoris (BF), tibialis anterior (TA), and flexor digitorum superficialis (FDS) muscles. mRNA expression of muscle regulatory factors was determined in BF. Fetal arterial hematocrit and oxygen content were 28% and 52% lower, respectively, in anemic fetuses. Fetal weight and whole body protein synthesis, breakdown, and accretion rates were not different between groups. Hindlimb length, however, was 7% shorter in anemic fetuses. TA and FDS muscles weighed less, and FDS myofiber area was smaller in anemic fetuses compared with controls. The percentage of Pax7⁺ myoblasts that expressed Ki67 was lower in BF and tended to be lower in FDS from anemic fetuses indicating reduced myoblast proliferation. There was less MYOD and MYF6 mRNA expression in anemic versus control BF consistent with reduced myoblast differentiation. These results indicate that fetal anemic hypoxemia reduced muscle growth. We speculate that fetal muscle growth may be improved by strategies that increase oxygen availability.

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.

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.

Deleterious effects of malaria in pregnancy on the developing fetus: a review on prevention and treatment with antimalarial drugs

All malaria infections are harmful to both the pregnant mother and the developing fetus. One in ten maternal deaths in malaria endemic countries are estimated to result from Plasmodium falciparum infection. Malaria is associated with a 3-4 times increased risk of miscarriage and a substantially increased risk of stillbirth. Current treatment and prevention strategies reduce, but do not eliminate, malaria's damaging effects on pregnancy outcomes. Reviewing evidence generated from meta-analyses, systematic reviews, and observational data, the first paper in this Series aims to summarise the adverse effects of malaria in pregnancy on the fetus and how the current drug treatment and prevention strategies can alleviate these effects. Although evidence supports the safety and treatment efficacy of artemisinin-based combination therapies in the first trimester, these therapies have not been recommended by WHO for the treatment of malaria at this stage of pregnancy. Intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine is contraindicated in the first trimester and provides imperfect chemoprevention because of inadequate dosing, poor (few and late) antenatal clinic attendance, increasing antimalarial drug resistance, and decreasing naturally acquired maternal immunity due to the decreased incidence of malaria. Alternative strategies to prevent malaria in pregnancy are needed. The prevention of all malaria infections by providing sustained exposure to effective concentrations of antimalarial drugs is key to reducing the adverse effects of malaria in pregnancy.

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.

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.