Hydrops Fetalis Research Articles

Resolution of Fetal Hydrops-not a Favorable Outcome in Congenital Pulmonary Malformation Type 1

Background: Congenital pulmonary airway malformations (CPAMs) comprise a spectrum of anatomical anomalies of the lungs and respiratory tree. The natural history of prenatally diagnosed CPAM varies from in utero resolution to progression to hydrops and intrauterine death. The majority of fetuses (90%) have a good outcome. However, in a minority (10%), the mass may grow so large that it is associated with complications and becomes life-threatening to the fetus. Clinical Description: Prenatal diagnosis of giant left CPAM type 1 was made at 24 weeks of gestation in a 29-year-old primigravida woman. The lesion consisted of multiple large cysts with a CPAM volume ratio of 4.7. Since the diagnosis, the mass was associated with nonimmune fetal hydrops and polyhydramnios which got worse throughout the following 4 weeks of gestation. Doppler studies remained normal until term. Management: The family received prenatal counseling. Parents refused termination of pregnancy and any other invasive or pharmacological therapy in light of the bad prognosis. The pregnancy was strictly monitored using standard fetal lung parameters. By 31 weeks' gestation, hydrops spontaneously improved to resolution but without any change in the size of the cysts. A baby girl was delivered at term, with birth asphyxia, who, despite all efforts by a multidisciplinary team, could not be revived. Autopsy and histopathological findings were compatible with type 1 CPAM. Conclusion: Hydrops is a well-known complication in fetuses with congenital cystic adenomatoid malformation. The present case reminds the possibility of its spontaneous resolution during pregnancy, even though the cyst size remains unaltered. The eventual neonatal survival depends not on the presence of hydrops but on the cyst volume and underlying lung hypoplasia.

A very rare disease of lymphatic malformation 6: five new patients and review of the literatur

Objective: Lymphatic Malformation 6 (MIM no:616843) is characterized by generalized edema, bilateral pleural effusions, ascites and non-immune hydrops fetalis. PIEZO1 gene has been associated with the LMPHM6 disorder. Here, we aimed to evaluate five patients from two different families, with various clinical presentations of generalized lymphatic dysplasia.
 Materials and Methods: Between January 2015 and January 2021, 5 cases with were evaluated with a pre-diagnosis of congenital lymphatic malformation. Whole exome sequencing was performed on the probands, and family segregation analysis was performed by Sanger sequencing.
 Results: We identified a novel compound heterozygous PIEZO1 gene: NM_001142864.4: c.4030_4032delGAG (E1344del)/ c.5455_5456delAA (K1819Efs*46) variants in the first family and a novel homozygous PIEZO1 gene: c.5876A>G (D1959G) variant in the second family.
 Conclusion: This study, which presents the clinical features and variations of five patients with long-term follow-up, contributed to the phenotypic and mutation spectrum of Lymphatic Malformation 6. The novel compound heterozygous E1344del/K1819Efs*46 variation leads to a premature stop codon that caused a shorter protein product. It was thought that two compound nonsense variations might be associated with the poor prognosis of family 1. Also, the second novel c.5876A>G (D1959G) biallelic homozygous mutation was thought to be associated with impaired PIEZO1 by causing loss of function. This study was the first LMPHM6 report from the Turkish population.
 Keywords: Neurofibromatosis type 1, Next generation DNA sequencing, NF1 gene, novel variants

Growth patterns in patients with mucopolysaccharidosis VII

ObjectiveThis study assessed growth patterns in patients with mucopolysaccharidosis (MPS) VII before enzyme replacement therapy. MethodsHeight, weight, and body mass index (BMI) measurements and Z-scores from patients from three clinical studies were compared with those from CDC healthy population growth charts. Relationships with age/sex and history of non-immune hydrops fetalis (NIHF) were assessed by linear regression and ANOVA, respectively. ResultsAmong 20 enrolled patients with MPS VII, height Z-scores were near normal until 1 year of age but declined thereafter, particularly among males. There was no consistent pattern in weight Z-score. BMI Z-scores were above normal and increased slightly with age among males and were slightly below normal among females. Male patients with a history of NIHF had greater declines in height and weight Z-scores over time versus males without history of NIHF. There was no clear effect of NIHF history on height and weight Z-scores in female patients. ConclusionsIn patients with MPS VII, declines in height Z-score began early in life, particularly among males, while changes in BMI varied by sex. Patients with MPS VII and a history of NIHF had greater declines in height Z-score with age than did patients without a history of NIHF.Clinical trial registration: This retrospective analysis included patients enrolled in an open-label phase 2 study (UX003-CL203; ClinicalTrials.gov, NCT02418455), a randomized, placebo-controlled, blind-start phase 3 study (UX003-CL301; ClinicalTrials.gov, NCT02230566), or its open-label, long-term extension (UX003-CL202; ClinicalTrials.gov, NCT02432144). Requests for individual de-identified participant data and the clinical study report from this study are available to researchers providing a methodologically sound proposal that is in accordance with the Ultragenyx data sharing commitment. To gain access, data requestors will need to sign a data access and use agreement. Data will be shared via secured portal. The study protocol and statistical analysis plan for this study are available on the relevant clinical trial registry websites with the tabulated results.

Autosomal recessive hyposegmentation of granulocytes in Australian Shepherd Dogs indicates a role for LMBR1L in myeloid leukocytes.

Pelger-Huët anomaly (PHA) in humans is an autosomal dominant hematological phenotype without major clinical consequences. PHA involves a characteristic hyposegmentation of granulocytes (HG). Human PHA is caused by heterozygous loss of function variants in the LBR gene encoding lamin receptor B. Bi-allelic variants and complete deficiency of LBR cause the much more severe Greenberg skeletal dysplasia which is lethal in utero and characterized by massive skeletal malformation and gross fetal hydrops. HG phenotypes have also been described in domestic animals and homology to human PHA has been claimed in the literature. We studied a litter of Australian Shepherd Dogs with four stillborn puppies in which both parents had an HG phenotype. Linkage analysis excluded LBR as responsible gene for the stillborn puppies. We then investigated the HG phenotype in Australian Shepherd Dogs independently of the prenatal lethality. Genome-wide association mapped the HG locus to chromosome 27 and established an autosomal recessive mode of inheritance. Whole genome sequencing identified a splice site variant in LMBR1L, c.191+1G>A, as most likely causal variant for the HG phenotype. The mutant allele abrogates the expression of the longer X2 isoform but does not affect transcripts encoding the shorter X1 isoform of the LMBR1L protein. The homozygous mutant LMBR1L genotype associated with HG is common in Australian Shepherd Dogs and was found in 39 of 300 genotyped dogs (13%). Our results point to a previously unsuspected function of LMBR1L in the myeloid lineage of leukocytes.

Diagnosis of α-thalassaemia by colorimetric gap loop mediated isothermal amplification

α-Thalassaemia is an inherited haemoglobin disorder that results from the defective synthesis of α-globin protein. Couples whom both carry the α-thalassaemia 1 gene are at risk of having a foetus with the most severe thalassaemia, Hb Bart’s hydrops fetalis, with a risk of maternal mortality. However, haematological parameters alone cannot distinguish between a α-thalassaemia 1 carrier and a homozygous α-thalassaemia 2, in which one α-globin gene has been deleted on each chromosome. A rapid and accurate molecular detection assay is essential for prevention of the disease in populations where α-thalassaemia 1 is common. Multiplex Gap-PCR analysis is widely used for diagnosis of α-thalassaemia. However, the technique requires a thermocycler and post-amplification processing, which limits its application in primary care or in rural areas in developing countries. Loop mediated isothermal amplification (LAMP) amplifies target DNA at a constant temperature and does not require a thermocycler. This study developed a colorimetric Gap-LAMP using malachite green to allow naked eye visualization of two deletional α-thalassaemia 1 commonly found in Asian populations, the Southeast Asian type (--SEA) and the Thai type (--THAI) deletions. The Gap-LAMP was performed on DNA samples from 410 individuals carrying various α-thalassaemia gene defects with 100% concordance with conventional Gap-PCR analysis. This method eliminates post-amplification processing or the use of expensive sophisticated equipment and allows screening large populations for the prevention and control of α-thalassaemia.

Molecular characterization of a novel 83.9-kb deletion of the α-globin upstream regulatory elements by long-read sequencing

Inherited deletions of upstream regulatory elements of α-globin genes give rise to α-thalassemia, which is an autosomal recessive monogenic disease. However, conventional thalassemia target diagnosis often fails to identify these rare deletions. Here we reported a family with two previous pregnancies of Hb Bart's hydrops fetalis and was seeking for prenatal diagnosis during the third pregnancy. Both parents had low level of Hemoglobin A2 indicating α-thalassemia. Conventional Gap-PCR and PCR-reverse dot blot showed the father carried –SEA deletion but did not identify any variants in the mother. Multiplex ligation-dependent probe amplification identified a deletion containing two HS-40 probes but could not determine the exact region. Finally, a long-read sequencing (LRS)-based approach directly identified that the exact deletion region was chr16: 48,642-132,584, which was located in the α-globin upstream regulatory elements and named (αα)JM after the Jiangmen city. Gap-PCR and Sanger sequencing confirmed the breakpoint. Both the mother and fetus from the third pregnancy carried heterozygous (αα)JM, and the fetus was normally delivered at gestational age of 39 weeks. This study demonstrated that LRS technology had great advantages over conventional target diagnosis methods for identifying rare thalassemia variants and assisted better carrier screening and prenatal diagnosis of thalassemia.

A novel HECW2 variant in an infant with congenital long QT syndrome

Pathogenic variants of HECW2 have been reported in cases of neurodevelopmental disorder with hypotonia, seizures, and absent language (NDHSAL; OMIM #617268). A novel HECW2 variant (NM_001348768.2:c.4343 T > C,p.Leu1448Ser) was identified in an NDHSAL infant with severe cardiac comorbidities. The patient presented with fetal tachyarrhythmia and hydrops and was postnatally diagnosed with long QT syndrome. This study provides evidence that HECW2 pathogenic variants can cause long QT syndrome along with neurodevelopmental disorders.

Perinatal-Lethal Non-Immune Fetal Hydrops Attributed to MECOM-associated Bone Marrow Failure.

Pathogenic variants in MECOM, a gene critical to the self-renewal and proliferation of hematopoietic stem cells, are known to cause a rare bone marrow failure syndrome associated with amegakaryocytic thrombocytopenia and bilateral radioulnar synostosis known as RUSAT2. However, the spectrum of disease seen with causal variants in MECOM is broad, ranging from mildly affected adults to fetal loss. We report two cases of infants born preterm who presented at birth with symptoms of bone marrow failure including severe anemia, hydrops, and petechial hemorrhages; radioulnar synostosis was not observed in either patient, and unfortunately, neither infant survived. In both cases, genomic sequencing revealed de novo variants in MECOM considered to be responsible for their severe presentations. These cases add to the growing body of literature that describe MECOM-associated disease, particularly MECOM as a cause of fetal hydrops due to bone marrow failure in utero. Furthermore, they support the use of a broad sequencing approach for perinatal diagnosis, as MECOM is absent from available targeted gene panels for hydrops, and highlight the importance of postmortem genomic investigation.

Unmasking the Culprit: Maternal Hyperthyroidism Presenting as Fetal Supraventricular Tachycardia and Hydrops

AbstractManagement of fetal supraventricular tachycardia at times can be tricky and challenging when they are secondary to underlying metabolic or hormonal problems. It can difficult to unmask the real culprit unless thorough evaluation is performed.

The Course, Prognosis, and Hand-Holding of Parents in Nonimmune Hydrops Fetalis—A Case Report with a Brief Review

AbstractHydrops fetalis (HF) is a serious fetal condition characterized by abnormal accumulation of fluid in fetal soft tissues and serous cavities. HF can be immune hydrops fetalis (IHF) or nonimmune hydrops fetalis (NIHF) depending upon the presence of antibodies in the mother. We report a case of euploid NIHF who delivered at 34 weeks and had spontaneous recovery. The baby had gross fetal ascites and mild pleural and pericardial effusion. After a thorough workup, no definite cause could be found. However, the ascites spontaneously resolved. The baby had many peaks and valleys during the initial 3 months of life, doing well at 6 months of age and is under follow-up. This case report highlights the practical workup and diagnostic algorithm of NIHF and provides an updated review.

Recurrent Nonimmune Fetal Hydrops Due to a Novel Pathogenic Variant in PIEZO1 Gene: A Case Report from South India

AbstractNonimmune fetal hydrops (NIFH) has underlying diverse etiology with generalized lymphatic dysplasia being one such cause. Lymphatic malformation-6 is a type of lymphatic dysplasia that is due to homozygous or compound heterozygous variants in the PIEZO1 gene. The clinical features associated with this condition during fetal life are nonimmune fetal hydrops that manifests with widespread lymphatic edema, with other systemic manifestations like pericardial/pleural effusions, chylothorax along with lymphangiectasia seen primarily in lungs and intestines. We present a case of recurrent NIFH in a family due to a novel pathogenic mutation in PIEZO1 gene. This variant was identified in homozygous state in all the three affected fetuses and in heterozygous state in both the parents. The couple were counseled regarding recurrence of this condition and given reproductive options for future pregnancies.

Transplacental Treatment of Fetal Tachyarrhythmia: Current Trends and Future Perspectives

Fetal arrhythmias complicate 1% of pregnancies. Although most of them have a benign and intermittent course, sustained fetal tachyarrhythmias constitute an emerging situation, which is associated with high fetal morbidity and mortality. However, one of the major milestones in fetal therapy is the pharmacologic management of fetal arrhythmias by crossing the placental barrier. To date, there is no consensus on the first-line antiarrhythmic treatment for fetal tachyarrhythmias. The role of sotalol in therapeutic management, the use of flecainide versus digoxin as first line of treatment, the need for fetal intramuscular treatment administration, or the best treatment in case of fetal hydrops are situations whose application or management are controversial. The current paper is a scoping review of observational and experimental evidence, addressing the types of best management strategies for each type of tachyarrhythmia and the optimal pharmacological dose, considering precautions and safety elements. Finally, we will highlight new therapeutic perspectives and future diagnostic and therapeutic strategies.

Genetic disorders and pregnancy outcomes of non-immune hydrops fetalis in a tertiary referral center

ObjectivesNon-immune hydrops fetalis (NIHF) is a non-specific symptom associated with a wide range of disorders. The prognosis of NIHF depends on the underlying etiology. In this study, we investigated the incidence of chromosomal abnormalities and Bart’s hydrops fetalis in pregnancies associated with NIHF in South China.MethodsWe conducted a retrospective review of NIHF pregnancies referred to the Fujian Provincial Maternity and Children’s Hospital between 2014 and 2018, excluding pregnancies with maternal alloimmunization. Routine karyotyping was performed on all 129 enrolled patients, and chromosomal microarray analysis was performed for 35 cases with a normal karyotype. In addition, α-thalassemia genotyping was performed to confirm the presence of Bart’s hydrops fetalis.ResultsChromosomal abnormalities were detected in 29.5% (38/129) of the cohort, including 37 cases with aneuploidy and one case with unbalanced structural rearrangement. Chromosomal microarray analysis performed on the 35 cases with a normal karyotype did not reveal any additional pathogenic variants. The proportions of chromosomal abnormalities declined with trimester progression, with frequencies of 65%, 30.1%, and 8.3% in the first, second, and third trimesters, respectively (p < 0.05). Bart’s hydrops fetalis was detected in 34.9% (45/129) of the cohort. Among the 46 (35.6%) cases with unknown etiology, 23 cases had other ultrasonic abnormalities characterized by poor outcomes, whereas seven cases with multiple cavity effusions that resolved or remitted prior to birth showed normal development during the 3–4 years of follow-up.ConclusionsIn South China, Bart’s hydrops fetalis and chromosomal abnormalities are the most common genetic etiologies of NIHF. Generalized skin edema and accompanying ultrasonic abnormalities are predictive of adverse outcomes, highlighting the need for intensive monitoring and better pregnancy management of NIHF patients.

Fetal and neonatal outcome in severe alloimmunization managed with intrauterine transfusion: 18-year experience in a tertiary referral hospital in China.

Hemolytic disease of the fetus and newborn (HDFN) due to red cell alloimmunization, is an important cause of fetal and neonatal morbidity and mortality. However, fetal and neonatal outcome of HDFN managed with intrauterine transfusion (IUT) in China are unknown. In addition, fetal and neonatal outcomes according to the type of maternal red cell alloantibodies involved and outcomes of hydrops fetalis are also unclear. The objective of this study was to evaluate fetal and neonatal outcomes of severe red-cell alloimmunization treated by IUT, to compare the outcomes according to the type of antibody, and to investigate the perinatal and postnatal outcomes of hydrops fetalis due to red cell alloimmunization. A retrospective study of pregnancies affected by HDFN and managed with IUT at a tertiary care university hospital in China between January 2001 and December 2018 was performed. Fetal and neonatal outcomes were investigated, and comparison of outcomes depending on the type of antibody and comparison of outcome between hydrops fetalis and fetuses without hydrops were also conducted. 244 IUTs were performed in 81 fetuses from 80 pregnancies. Anti-RhD was the major etiology of HDFN requiring IUT (71.6%). The fetal survival rate was 90.1%. The survival rate of the hydropic fetuses was significantly lower than those of the non hydropic fetuses (61.2% vs. 95.6%) (P = 0.002**). Compared with non hydropic fetuses, hydropic fetuses had significantly lower gestational age and lower hemoglobin level at first IUT. The neonatal survival rate was 98.6%. Exchange transfusions were required in 26% of the neonates. 30.1% of neonates had late anemia and required top-up transfusions, and hydropic fetuses required more late top-up transfusions than fetuses without hydrops. No significant difference in fetal and neonatal outcomes was found among the four subgroups stratified by the antibody involved. Our study demonstrates that IUT is an effective and safe therapy for severe HDFN at our institution. Early detection and treatment of hydrops is critical for perinatal outcomes. Particular attention should be paid to late postnatal anemia in affected neonates and top-up transfusion is still commonly needed.

Neonatal Lymphatic Flow Disorder.

To examine and discuss patients diagnosed with acquired and congenital chylothorax in the neonatal period in the light of the literature. The files of newborns followed-up in the neonatal intensive care unit (NICU) and diagnosed with congenital and acquired chylothorax were reviewed retrospectively. Patients with isolated chylothorax were classified as Group 1 and those with multiple lymphatic flow disorders were classified as Group 2. Antenatal and clinical features were recorded and compared between the groups. Thirteen infants were diagnosed with chylothorax; 92.3% (n = 12) of the patients were congenital. The rate of antenatal diagnosis was 61.5% (n = 8). Eight patients (61.5%) were diagnosed with hydrops fetalis. Among the cases in Group 1 and Group 2, receiving ocreotide and the incidence of sepsis (p = 0.05) were partially significant. Seven of the patients (66.6%) responded to medium chain triglycerides (MCT), and complete resolution was seen in 6 (85.7%) of the responders. Complete resolution of chylothorax fluid was observed in 7 (77.7%) of nine patients who responded to ocreotide treatment. In neonatal chylothorax, the postnatal period includes a multidisciplinary approach that requires drug therapy, dietary modifications, drainage of pleural fluid, and rarely, surgery.

Ultrasonographic classification of 26 cases of fetal umbilical-portal-systemic venous shunts and the correlations with fetal chromosomal abnormalities

ObjectiveTo investigate the ultrasonographic classification of fetal umbilical-portal-systemic venous shunts (UPSVS) and the correlations with fetal chromosomal abnormalities.MethodsWe retrospectively analyzed the ultrasound characteristics and the corresponding chromosomal abnormalities of 26 cases of fetal UPSVS prenatally diagnosed.ResultsA total of 26 fetuses diagnosed as UPSVS were included, including four cases of type I UPSVS, ten of type II, three of type IIIA, and nine of type IIIB. Four cases of type I were all complicated by fetal heart enlargement and heart insufficiency, of which one case had multiple malformations, and all four cases terminated pregnancies. Six of ten cases of type II terminated pregnancies, including four of Down’s syndrome, one of twin reversed arterial perfusion sequence, one of fetal edema but with normal copy number variation (CNV) by chorionic villus sampling. The other four of ten cases were isolated type II with normal chromosomes, which were delivered at full term and were normal in growth and development when followed up 34 months after birth. Three cases of type IIIA all terminated pregnancies, of which one had multiple malformations, one had right multicystic dysplastic kidney, and one had fetal heart enlargement and heart failure. Among nine of type IIIB, seven with chromosomal abnormalities and/ or complicated malformations terminated pregnancies, and two with isolated type IIIB and normal chromosomes were delivered at full term, and were normal in growth and development (one was followed up to 33 months after birth and the other 20 months after birth).ConclusionFetal UPSVS can be clearly diagnosed and typed by prenatal ultrasonography. Fetal prognosis is determined by the types of UPSVS and complicated malformations and/ or chromosomal abnormalities. The probability of fetal chromosomal abnormalities in UPSVS fetuses is related to the ultrasonographic classification.

Investigation into the genetics of fetal congenital lymphatic anomalies.

Congenital lymphatic anomalies (LAs) arise due to defects in lymphatic development and often present in utero as pleural effusion, chylothorax, nuchal and soft tissue edema, ascites, or hydrops. Many LAs are caused by single nucleotide variants, which are not detected on routine prenatal testing. Demographic data were compared between two subcohorts, those with clinically significant fetal edema (CSFE) and isolated fetal edema. A targeted variant analysis of LA genes was performed using American College of Medical Genetics criteria on whole exome sequencing (WES) data generated for 71 fetal edema cases who remained undiagnosed after standard workup. CSFE cases had poor outcomes, including preterm delivery, demise, and maternal preeclampsia. Pathogenic and likely pathogenic variants were identified in 7% (5/71) of cases, including variants in RASopathy genes, RASA1, SOS1, PTPN11, and a novel PIEZO1 variant. Variants of uncertain significance (VOUS) were identified in 45% (32/71) of cases. In CSFEs, VOUS were found in CELSR1, EPHB4, TIE1, PIEZO1, ITGA9, RASopathy genes, SOS1, SOS2, and RAF1. WES identified pathogenic and likely pathogenic variants and VOUS in LA genes in 51% of fetal edema cases, supporting WES and expanded hydrops panels in cases of idiopathic fetal hydrops and fluid collections.

Non immune hydrops fetalis due to Parvovirus B19 infection. A case report

Backround: The term “hydrops fetalis” refers to excessive accumulation of pathologic serous fluid within the fetal soft tissues and body cavities. There are two categories, the immune and the nonimmune hydrops (NIHF). Currently 90 percent of cases of hydrops are nonimmune, because of the decrease of incidence of immune with the advent of anti-D immune globulin. Case presentation: We present a case of Parvovirus B19 (PB19) infection that resulted in NIHF. Fetus had severe ascites, mild pericardial effusion and mild myocardial dilation, that appeared during the 30th gestational week. Fetal evaluation with sonography was repeated every week and the fetal growth curves, Dopplers and amniotic fluid index were normal. Each week there was a gradual recession of the effusions until the 36th gestational week, when they eventually resolved without any treatment. After delivery, the neonate was symptom – free. Conclusions: The cause of NIHF is identified in at least 60 percent prenatally and in more than 80 percent postnatally, while only 40 percent of pregnancies with NIHF result in a liveborn neonate. The prognosis is heavily dependent on etiology. Diaplacental transmission of PB19 on second trimester can cause fetal complications like hydrops, premature rapture of membranes, even fetal loss in about 30 percent. These cases should be closely followed in a Fetal Medicine Unit, especially if there is evidence of fetal anemia or hydrops.

Neonatal Hemochromatosis: Systematic Review of Prenatal Ultrasound Findings-Is There a Place for MRI in the Diagnostic Process?

Neonatal hemochromatosis (NH) is an uncommon, severe disorder that results in fetal loss or neonatal death due to liver failure. NH is currently regarded as the phenotypic expression of gestational alloimmune liver disease (GALD). The diagnosis of NH-GALD is rarely prenatally established. In addition to providing a systematic review of the prenatal features that are identifiable using ultrasound (US) and MRI, we suggest a prenatal diagnosis algorithm for use in suspected NH during the first affected pregnancy. From a total of 586 database entries identified in PubMed, Google Scholar, and ResearchGate, we selected 18 studies published from 1993 to 2021 that reported maternal medical and obstetric history, prenatal ultrasound findings, and postpartum outcomes. We investigated the ultrasound and MRI features of these studies, along with the outcome due to this condition. A total of 74 cases were identified. The main reported prenatal US finding was fetal growth restriction (FGR) (33%), followed by oligohydramnios (13%) and hydrops fetalis (13%), with 13% cases described as uneventful. Other rare prenatal findings were fetal anemia, ascites, and abnormal fetal liver and spleen. Most pregnancies ended with fetal/perinatal death or therapeutic interruption of pregnancy. Favorable evolution with treatment (ensanguine transfusion and intravenous immunoglobulin (IVIG)) was reported for only 7% of fetuses. Using T2-weighted MRI, fetal extrahepatic siderosis confirmed prenatally in two cases and postnatally in 11 cases. IVIG treatment throughout subsequent pregnancies was found to significantly improve fetal prognosis. MRI should be indicated in selected cases of oligohydramnios, fetal hydrops, fetal hepatomegaly, ascites, or unexplained FGR or anemia after ruling out all other more frequently encountered conditions. MRI can be used to detect iron overload in the liver and extrahepatic siderosis.

Non‐immune hydrops fetalis: a practical guide for obstetricians

Key content Hydrops fetalis is the accumulation of two or more fetal fluid collections, including pericardial effusion, pleural effusion(s), ascites and skin oedema. In the absence of red cell alloimmunisation, hydrops fetalis is non‐immune and affects approximately 1 in 2000 pregnancies. Non‐immune hydrops fetalis (NIHF) is associated with severe perinatal morbidity/mortality and significant maternal risks, including maternal mirror syndrome. Priorities for clinicians are determining the cause antenatally to optimise management and discuss treatment options, if available. Systematic reviews have indicated that a cause can be identified prenatally in ~60% cases. Recent evidence indicates fetal exome sequencing can provide a diagnosis in 30% of previously unexplained cases. Learning objectives To understand causes of NIHF and its association with perinatal and maternal morbidity and mortality To appreciate the basis for investigations for NIHF, including exome sequencing To understand how care can be effectively shared by referring units and tertiary fetal medicine units