Diagnostic yield from prenatal exome sequencing for non-immune hydrops fetalis: A systematic review and meta-analysis.

Non-immune hydrops fetalis (NIHF) has multiple genetic etiologies diagnosable by exome sequencing (ES). We evaluated the yield of prenatal ES for NIHF, and the contribution of additional clinical findings and history. Systematic review was performed with PROSPERO tag 232951 using CINAHL, PubMed, and Ovid MEDLINE from January 1, 2000 through December 1, 2021. Selected studies performed ES to augment standard prenatal diagnostic approaches. Cases meeting a strict NIHF phenotype were tabulated with structured data imputed from papers or requested from authors. Genetic variants and diagnostic outcomes were harmonized across studies using current ACMG and ClinGen variant classification guidelines. Thirty-one studies reporting 445 NIHF cases had a 37% (95% CI: 32%-41%) diagnostic rate. There was no significant difference between isolated NIHF and NIHF with fetal malformations or between recurrent and simplex cases. Diagnostic rate was higher for consanguineous than non-consanguineous cases. Disease categories included RASopathies (24%), neuromuscular (21%), metabolic (17%), lymphatic (13%), other syndromes (9%), cardiovascular (5%), hematologic (2%), skeletal (2%), and other categories (7%). Inheritance patterns included recessive (55%), dominant (41%), and X-linked (4%). ES should be considered in the diagnostic workup of NIHF with and without associated ultrasound findings regardless of history of recurrence or consanguinity.

Perinatal presentations of non-immune hydrops fetalis due to recessive PIEZO1 disease: A challenging fetal diagnosis.

Hydrops fetalis is a rare disorder associated with significant perinatal complications and a high perinatal mortality of at least 50%. Nonimmune hydrops fetalis (NIHF) is more frequent and results from a wide variety of etiologies. One cause of NIHF is lymphatic malformation 6 (LMPHM6) due to biallelic loss-of-function (LoF) variants in PIEZO1. Most individuals are diagnosed postnatally and only few clinical data are available on fetal presentations. We report six novel biallelic predicted LoF variants in PIEZO1 identified by exome sequencing in six fetuses and one deceased neonate from four unrelated families affected with LMPHM6. During the pregnancy, most cases are revealed by isolated NIHF at second trimester of gestation. At post-mortem examination ascites, pleural effusions and telengectasies can guide the etiological diagnosis. We aim to further describe the perinatal presentation of this condition which could be underdiagnosed.

Isolated non-immune hydrops fetalis: an observational study on complete spontaneous resolution, perinatal outcome, and long-term follow-up.

PURPOSE: The aim of our study was to investigate spontaneous resolution and postnatal outcome in non-immune hydrops fetalis (NIHF). We specifically studied NIHF cases that occurred without any other anomalies in the prenatal diagnostic workup, defined as isolated NIHF (iNIHF). METHODS: To identify iNIHF we retrospectively classified prenatal findings of 700 NIHF singletons, diagnosed in our prenatal referral center between 1997 and 2016. We studied the occurrence of prenatal resolution in iNIHF and linked it to the perinatal outcome. We obtained long-term outcome by contacting the parents, children, and the pediatricians and listed all functional and structural anomalies and temporary logopedic, psychosocial and motoric impairments. RESULTS: Among 70 iNIHF cases, 54 (77.1%) resolved completely prenatally. The baby-take-home rate was 98.1% in these cases. In contrast, the baby-take-home rate in the subgroup without complete resolution was 25.0%. We achieved pediatric long-term outcome in 27 of 57 survivors (47.4%) of iNIHF with a mean follow-up period of 10.9 years. Among these 27 children, fetal hydrops had completely resolved prenatally in 26 cases and had regressed to a mild effusion in one case. In the pediatric development, two children had significant functional impairment and two children showed recurrent skin edema. CONCLUSION: Complete spontaneous resolution was the most common intrauterine course of iNIHF in our collective. Completely resolved iNIHF had a favorable perinatal outcome in our study. Our data on the long-term outcomes are consistent with the assumption of an increased rate of functional impairments. TRIAL REGISTRY: Internal study number of Heinrich-Heine-University, Duesseldorf: 6177R. Date of registration: December 2017.

A Gardos channelopathy associated with nonimmune hydrops and fetal loss.

Dehydrated hereditary stomatocytosis (DHS) (MIM#194380) is a rare autosomal dominant disorder of red blood cell permeability, characterized by a partially or fully compensated nonimmune hemolytic anemia. PIEZO1 is the major gene involved with hundreds of families described, some of which present transient perinatal edema of varying severity. A smaller subset of individuals harbors pathogenic variants in KCNN4, sometimes referred as "Gardos channelopathy." Up to now, only six pathogenic variants in KCNN4 have been reported in 13 unrelated families. Unlike PIEZO1-DHS, neither perinatal edema nor fetal loss has ever been observed linked to KCNN4-DHS. We report the first fetal loss due to non-immune hydrops fetalis related to a pathogenic 28 bp deletion (NM_002250.2: c.1109_1119+17del) in KCNN4. This observation underlies the need for very close monitoring of pregnancies when one parent is affected by DHS regardless of genotype (PIEZO1 or KCNN4).

Fetal hydrops and the Incremental yield of Next-generation sequencing over standard prenatal Diagnostic testing (FIND) study: prospective cohort study and meta-analysis.

OBJECTIVE: To determine the incremental yield of exome sequencing (ES) over chromosomal microarray analysis (CMA) or karyotyping in prenatally diagnosed non-immune hydrops fetalis (NIHF). METHODS: A prospective cohort study (comprising an extended group of the Prenatal Assessment of Genomes and Exomes (PAGE) study) was performed which included 28 cases of prenatally diagnosed NIHF undergoing trio ES following negative CMA or karyotyping. These cases were combined with data from a systematic review of the literature. MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases were searched electronically (January 2000 to October 2020) for studies reporting on the incremental yield of ES over CMA or karyotyping in fetuses with prenatally detected NIHF. Inclusion criteria for the systematic review were: (i) at least two cases of NIHF undergoing sequencing; (ii) testing initiated based on prenatal ultrasound-based phenotype; and (iii) negative CMA or karyotyping result. The incremental diagnostic yield of ES was assessed in: (i) all cases of NIHF; (ii) isolated NIHF; (iii) NIHF associated with an additional fetal structural anomaly; and (iv) NIHF according to severity (i.e. two vs three or more cavities affected). RESULTS: In the extended PAGE study cohort, the additional diagnostic yield of ES over CMA or karyotyping was 25.0% (7/28) in all NIHF cases, 21.4% (3/14) in those with isolated NIHF and 28.6% (4/14) in those with non-isolated NIHF. In the meta-analysis, the pooled incremental yield based on 21 studies (306 cases) was 29% (95% CI, 24-34%; P < 0.00001; I2 = 0%) in all NIHF, 21% (95% CI, 13-30%; P < 0.00001; I2 = 0%) in isolated NIHF and 39% (95% CI, 30-49%; P < 0.00001; I2 = 1%) in NIHF associated with an additional fetal structural anomaly. In the latter group, congenital limb contractures were the most prevalent additional structural anomaly associated with a causative pathogenic variant, occurring in 17.3% (19/110) of cases. The incremental yield did not differ significantly according to hydrops severity. The most common genetic disorders identified were RASopathies, occurring in 30.3% (27/89) of cases with a causative pathogenic variant, most frequently due to a PTPN11 variant (44.4%; 12/27). The predominant inheritance pattern in causative pathogenic variants was autosomal dominant in monoallelic disease genes (57.3%; 51/89), with most being de novo (86.3%; 44/51). CONCLUSIONS: Use of prenatal next-generation sequencing in both isolated and non-isolated NIHF should be considered in the development of clinical pathways. Given the wide range of potential syndromic diagnoses and heterogeneity in the prenatal phenotype of NIHF, exome or whole-genome sequencing may prove to be a more appropriate testing approach than a targeted gene panel testing strategy. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Non-immune hydrops fetalis was rare in Sweden during 1997-2015, but cases were associated with complications and poor prognosis.

AIM: The study was designed to document the incidence of non-immune hydrops fetalis (NIHF) at birth and characterise associated outcomes and obstetric complications. METHODS: Data on more than 1.9 million births were extracted from the Swedish Birth Register for 1997-2015. Pregnancies not affected by NIHF served as controls. National registers on mortality and hospitalisations provided follow-up information. RESULTS: There were 309 cases of NIHF at birth corresponding to an incidence of 1.6 per 10 000, lower than in previous studies. NIHF was more frequent in mothers aged ≥35 years and with a history of stillbirth. Preterm delivery occurred in 77.7% in the NIHF group, including 31.7% before 32 weeks of gestation. Multiple births and Caesarean sections were reported more frequent in the NIHF group. NIHF was associated with poor outcome with 14.6% stillbirths and in 26.5% early neonatal death. Overall, 58.7% of live-born children with NIHF were alive at 12 months compared with 99.7% of controls. The most common causes of death were cardiovascular diseases and thoracic abnormalities. CONCLUSION: NIHF at birth is associated with obstetric complications and poor prognosis for the neonate related to underlying disease. The low incidence of NIHF observed in this study may reflect well-developed antenatal care.

No. 363-Investigation and Management of Non-immune Fetal Hydrops.

OBJECTIVE: To describe the current investigation and management of non-immune fetal hydrops with a focus on treatable or recurring etiologies. OUTCOMES: To provide better counselling and management in cases of prenatally diagnosed non-immune hydrops. EVIDENCE: Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in 2017 using key words (non-immune hydrops fetalis, fetal hydrops, fetal therapy, fetal metabolism). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, observational studies, and significant case reports. Additional publications were identified from the bibliographies of these articles. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to September 2017. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinicalpractice guideline collections, clinical trial registries, and national and international medical specialty societies. BENEFITS, HARMS, AND COSTS: These guidelines educate readers about the causes of non-immune fetal hydrops and its prenatal counselling and management. It also provides a standardized approach to non-immune fetal hydrops, emphasizing the search for prenatally treatable conditions and recurrent genetic etiologies. VALUES: The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care.

Inborn errors of metabolism in a cohort of pregnancies with non-immune hydrops fetalis: a single center experience.

OBJECTIVE: The purpose of this study was to determine the frequency of non-immune hydrops fetalis (NIHF) among all pregnancies referred for prenatal care at Sultan Qaboos University Hospital (SQUH) during the study period and to evaluate the underlying etiologies of NIH. STUDY DESIGN: All pregnancies referred to SQUH between February 2014 and December 2015 were identified, and all pregnancies meeting the diagnosis of NIHF were included in this study. All cases of NIHF referred to our center during this period underwent standard systematic diagnostic work-up that included biochemical and molecular studies in addition to the standard investigations for hydrops fetalis. Clinical characteristics and results of the diagnostic work-up were retrospectively reviewed. RESULTS: A total of 3234 pregnancies were referred for prenatal care at SQUH during the study period, and 12 pregnancies were affected by NIHF. An underlying diagnosis was established in nine cases, and the majority of cases (7/9) were caused by inborn errors of metabolism (IEM). These included a novel homozygous variant in the AARS2 gene (5/7) and two cases of galactosialidosis (2/7). CONCLUSION: IEM was a major cause of NIHF in this cohort. The AARS2 variant accounts for a significant number of cases with NIHF in this cohort of Omani patients.

Perinatal mortality in Japanese women diagnosed with gestational diabetes mellitus and diabetes mellitus.

AIMS: The objective of this study was to determine how many pregnant Japanese women with diabetes mellitus (DM)/gestational diabetes mellitus (GDM) experience perinatal mortality in the presence of fetal anomalies. METHODS: Our investigation included data from 205 secondary/tertiary obstetric facilities located widely in Japan. The Japan Ministry of Health, Labour and Welfare Vital Statistics of Japan was used for comparison. RESULTS: Of 237 941 women giving birth at 205 hospitals, 1796 (0.8%) and 13 037 (5.5%) had DM and GDM, respectively. The perinatal mortality rates (per 1000 births) were 10.6 (19/1796) for women with DM, 5.2 (68/13037) for women with GDM, and 3.7 (7612/2039504) for the general Japanese population. Detailed information was available for 63 (72%) of the 87 perinatal deaths occurring in women with diabetes including DM and GDM; fetal anomalies were associated with 40% (25/63) of perinatal deaths, exceeding 16% (1211/7612) in the general Japanese population (P < 0.0001). The leading four fetal anomalies associated with perinatal mortality in women with diabetes were fetal trisomy (6 cases: 1 of trisomy-13 and 5 of trisomy-18), non-immune hydrops fetalis (5 cases), cardiac deformities (3 cases) and holoprosencephaly (2 cases). CONCLUSIONS: Perinatal mortality was more likely to occur in women with glucose intolerance. In the Japanese infants that succumbed to perinatal mortality, fetal anomaly was more prevalent in those born to women with a glucose intolerance than in those born to the general population.

Perinatal and one-year outcomes of non-immune hydrops fetalis by etiology and age at diagnosis.

AIM: The prognosis for non-immune hydrops fetalis (NIHF) is still poor despite progress in perinatal care. We have examined perinatal and 1-year outcomes for NIHF in relation to gestational age at diagnosis and underlying etiology in order to identify predictors of mortality. METHODS: A retrospective review was conducted of 92 pregnancies with NIHF managed in hospital between 2000 and 2012. The gestational age at diagnosis, etiology, perinatal outcome, and 1-year outcome were recorded, and their associations assessed. RESULTS: A total of 41 of 92 cases (45%) resulted in fetal death, 33 patients (36%) survived to 1 year, but only 15 of the 33 survivors were developmentally intact. Aneuploidy was the most common cause of NIHF (27%; 25/92). Of the 34 patients who were diagnosed before 22 weeks, 29 fetuses (85%) died, and four (12%) survived to 1 year without developmental delay. Meanwhile, of the 26 patients diagnosed after 30 weeks, 18 (69%) survived to 1 year. Of those 18, seven (27%) were developmentally intact. Approximately half of the pregnancies with cardiac anomalies (8/13) resulted in intrauterine fetal death (IUFD) or early neonatal death. Aneuploidy was associated with a high frequency of IUFD, and of the remaining five surviving newborns, three had developmental delay. CONCLUSION: The prognosis for NIHF differs according to underlying etiology and gestational age at diagnosis. NIHF diagnosed early in gestation is associated with poor outcome. Knowledge of the primary etiology is important for counseling and therapy.

Mediastinal teratoma with hydrops fetalis in a newborn and development of chronic respiratory insufficiency.

BACKGROUND: Mediastinal fetal teratoma can be detected as a mass in the chest during a routine prenatal ultra-sound screening. Because of the pressure on mediastinal structures it can be the cause of non-immune hydrops fetalis and polyhydramnion. The development of hydrops fetalis leads to fetal death or premature delivery in most reported cases. Early surgical removal is important, but, the result of treatment depends on the stage of development of mediastinal organs and complications in the postoperative period. CASE REPORT: A 31-year-old gravida carrying twins, with spontaneous membrane rupture at 32 weeks gestation underwent urgent caesarean section after antenatal ultrasound revealed severe polyhydramnion and hydrops fetalis in geminus A. The child was intubated immediately after birth due to severe respiratory distress. Ultrasound and X-ray revealed a tumour mass in the right hemithorax. Tumour resection was performed at the age of 7 days. Histology examination revealed an encapsulated immature teratoma. The postoperative course was complicated with respiratory insufficiency which turned into chronic at the age of eight months. CONCLUSION: This is the fifth reported child with fetal mediastinal teratoma and severe hydrops fetalis that survived the neonatal period. Additional diagnostic search revealed abnormal course of both pulmonary arteries, which was probably one of the main causes of respiratory insufficiency.

Disease characteristics, effectiveness, and safety of vestronidase alfa for the treatment of patients with mucopolysaccharidosis VII in a novel, longitudinal, multicenter disease monitoring program.

BACKGROUND: Mucopolysaccharidosis VII (MPS VII) is an ultra-rare, autosomal recessive, debilitating, progressive lysosomal storage disease caused by reduced activity of ß-glucuronidase (GUS) enzyme. Vestronidase alfa (recombinant human GUS) intravenous enzyme replacement therapy is an approved treatment for patients with MPS VII. METHODS: This disease monitoring program (DMP) is an ongoing, multicenter observational study collecting standardized real-world data from patients with MPS VII (N ≈ 50 planned) treated with vestronidase alfa or any other management approach. Data are monitored and recorded in compliance with Good Clinical Practice guidelines and planned interim analyses of captured data are performed annually. Here we summarize the safety and efficacy outcomes as of 17 November 2022. RESULTS: As of the data cutoff date, 35 patients were enrolled: 28 in the Treated Group and seven in the Untreated Group. Mean (SD) age at MPS VII diagnosis was 4.5 (4.0) years (range, 0.0 to 12.4 years), and mean (SD) age at DMP enrollment was 13.9 (11.1) years (range, 1.5 to 50.2 years). Ten patients (29%) had a history of nonimmune hydrops fetalis. In the 23 patients who initiated treatment prior to DMP enrollment, substantial changes in mean excretion from initial baseline to DMP enrollment were observed for the three urinary glycosaminoglycans (uGAGs): dermatan sulfate (DS), -84%; chondroitin sulfate (CS), -55%; heparan sulfate (HS), -42%. Also in this group, mean reduction from initial baseline to months 6, 12, and 24 were maintained for uGAG DS (-84%, -87%, -89%, respectively), CS (-70%, -71%, -76%, respectively), and HS (+ 3%, -32%, and - 41%, respectively). All adverse events (AEs) were consistent with the known vestronidase alfa safety profile. No patients discontinued vestronidase alfa. One patient died. CONCLUSIONS: To date, the DMP has collected invaluable MPS VII disease characteristic data. The benefit-risk profile of vestronidase alfa remains unchanged and favorable for its use in the treatment of pediatric and adult patients with MPS VII. Reductions in DS and CS uGAG demonstrate effectiveness of vestronidase alfa to Month 24. Enrollment is ongoing.

A de novo homozygous missense mutation of the GUSB gene leads to mucopolysaccharidosis type VII identification in a family with twice adverse pregnancy outcomes due to non-immune hydrops fetalis.

Non-immune hydrops fetalis (NIHF) is a common and severe manifestation of many genetic disorders. The ultrasound is an ideal method for diagnosing hydrops fetalis during pregnancy. Since most NIHFs do not have an identifiable cause, determining the underlying etiology remains a challenge for prenatal counseling. Due to advancements in exome sequencing, the diagnostic rates of NIHF have recently increased. As reported here, DNA was extracted from the amniotic fluid of a pregnant woman who was prenatally diagnosed with a NIHF type of unclear origin. Amniocentesis sampling demonstrated a normal female karyotype and copy number variation(CNVs) without alterations. Tri-whole exome sequencing (WES) was conducted to identify possible causative variants. In the fetus, a de novo genetic mutation was identified as a homozygous form. The mutation was located on the glucuronidase beta (GUSB) gene: NM_000181.3: c.1324G > A; p. Ala442Thr; Chr7:65439349, which leads to mucopolysaccharidosis type VII. This mutation was inherited from the parents and was first reported to be related to NIHF. We conclude that the use of WES is beneficial for NIHF cases whose prognosis has not been explained by standard genetic testing.

Non-immune hydrops fetalis: A prospective study of 53 cases.

Non-immune hydrops fetalis (NIHF) is a symptom caused by a heterogeneous group of conditions. Diagnostic investigations may constitute a real challenge. This study aimed to evaluate prospectively and systematically a series of NIHF cases using a research protocol expanded for studying inborn errors of metabolism (IEM) during 2 years-2010 and 2011. We also reviewed the frequency of IEM among the NIHF reported in literature. A clinical or etiopathogenic diagnosis was reached in 46 (86.8%) of the 53 studied cases. The main diagnostic groups were chromosomal anomalies (28.3%), syndromic (18.9%), isolated cardiovascular anomaly (7.5%) and congenital infection (7.5%). Metabolic causes were found in 5.7%, all lysosomal storage disorders (LSD). In seven (13.2%), no diagnosis was found in part because of incomplete evaluation. The hydrops was identified prenatally in 90.5% of cases. In 5.7% a spontaneous and complete resolution of the hydrops occurred during pregnancy. Overall mortality was 75.5%. The IEM frequency in the present study (5.7%) was higher than that usually reported. We suggest performing studies directed to IEMs if the more common causes are excluded.

RETIRED: Investigation and management of non-immune fetal hydrops.

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

Ce document a été archivé, car il contient des informations périmées. Il ne devrait pas être consulté pour un usage clinique, mais uniquement pour des recherches historiques. Veuillez consulter le site web du journal pour les directives les plus récentes.

The Cardiovascular Profile Score in Patients with Non-immune Hydrops Fetalis and Cardiac Anomalies - a Pilot Study.

The purpose of this paper is to explore whether the cardiovascular profile score (CVPS) correlates with fetal outcome in patients with non-immune hydrops fetalis (NIHF) and cardiac anomalies. In this retrospective study, we included fetuses with NIHF and the suspicion of a cardiac anomaly in prenatal ultrasound. The CVPS was calculated using information obtained by fetal echocardiographic examination. Feto-neonatal mortality (FNM) was defined as intrauterine fetal demise or death in the first 6 months of life. We reviewed 98 patients, who were referred to the Department of Obstetrics and Gynecology of the Johannes Gutenberg University in Mainz with the diagnosis of NIHF between January 2007 and March 2021. By eighteen of them, the suspicion of a cardiac anomaly was raised. After exclusion of six pregnancies (one termination of pregnancy and five because of incomplete data), 12 cases were left for analysis. Mean gestational age at which the CVPS was calculated was 29 + 2 weeks. Two fetuses died in utero. Of the remaining ten hydropic fetuses, three newborns died in the neonatal period, and seven survived after a 6-month surveillance period. Median CVPS of all fetuses was 6 points. Surviving fetuses showed statistically significantly higher CVPS values (median 8 points) than fetuses with FNM (median 5 points, p value = 0.009). Our results point towards a positive association between CVPS and fetal outcome in fetuses with NIHF and cardiac anomalies. The CVPS appears to be a useful marker in the assessment of heart failure in utero.

Fetal Inferior Vena Cava Thrombosis Associated With Non-Immune Hydrops Fetalis and Maternal Mirror Syndrome.

Prenatal assessment of the inferior vena cava (IVC) should be considered in pregnancies with atypical presentations of fetal ascites and placentomegaly. We examine a case of a 25-year-old gravida 2 para 1 type 1 diabetic female at 29 and 4/7 weeks' gestation. Ultrasound (US) showed fetal ascites and placentomegaly with increased middle cerebral artery peak systolic velocity (MCA-PSV) suspicious of fetal anemia. Cordocentesis with intrauterine transfusion briefly resolved the fetal ascites, though the mother developed pulmonary edema and pleural effusion, suggestive of mirror syndrome. On US, fetal ascites returned and progressed to non-immune hydrops fetalis, prompting delivery. Neonatal US revealed a heterogenous and calcified thrombus within the IVC.

An Investigation of the Etiologies of Non-Immune Hydrops Fetalis in the Era of Next-Generation Sequence-A Single Center Experience.

(1) Background: Numerous etiologies may lead to non-immune hydrops fetalis (NIHF). However, the causes remain unclear in half of NIHF cases following current standard assessment. The application of prenatal chromosomal microarray analysis (CMA) and exome sequencing (ES) can improve the identification of the etiologies. This study aimed to investigate the etiologies of NIHF in the era of next-generation sequence (NGS) following a unified prenatal work-up flow for diagnosis. (2) Methods: A retrospective analysis was conducted on NIHF cases that were collected prospectively to explore the underlying etiologies according to a unified prenatal diagnosis work-up flow at Shanghai First Maternity and Infant Hospital between Jan 2016 and Dec 2019. The medical records for all NIHF cases were reviewed, and the causes of NIHF were classified as confirmed (diagnostic), suspected, or unknown. (3) Results: Prenatal and postnatal medical records for a total of 145 NIHF cases were reviewed, 48.3% (70/145) of the cases were identified to be with confirmed etiologies, and 10.3% (15/145) with suspected etiologies. Among 85 cases with confirmed or suspected etiologies, 44.7% were diagnosed with genetic disorders, 20% with chylothorax/chyloascites diagnosed postnatally, 12.9% with fetal structural anomalies, 12.9% with fetal anemia, 7% (6 cases) with fetal arrhythmia, and 2.3% (2 cases) with placenta chorioangioma. In cases with genetic disorders, 8 aneuploidies were detected by CMA, and 30 cases had single-gene disorders identified by ES (29/30) or targeted gene panel (1/30). There were still 41.4% cases (60/145) with unknown causes after this unified prenatal diagnostic work-up flow. (4) Conclusions: In the era of NGS, the causes of NIHF were identified in 58.6% of cases, with genetic disorders being the most common ones. NGS is helpful in determining the genetic etiology of NIHF when CMA results cannot explain NIHF, but 41.4% of cases were still with unknown causes under the unified prenatal diagnostic work-up flow in this single-center study.

Human parvovirus B19 infection in a pregnant patient resulting in severe hydrops, foetal death and persistent infection.

Human parvovirus B19 (B19V) is the aetiological agent of erythema infectiosum. Primary infection during pregnancy can be transmitted to the foetus and cause foetal abnormalities related to depletion of erythrocyte progenitor cells, including congenital anaemia, hydrops, and foetal death. In this paper we report the detection of B19V infection in a pregnant patient, which onset occurred without appreciable signs and symptoms until she developed inappropriate contractions for gestational age and fluid loss. B19V infection resulted in severe hydrops fetalis with a fatal course for the foetus, while persisted in the mother at least 12 months after foetal death. The objective of this report is to highlight the importance of optimizing B19V diagnosis through early suspicion and testing during pregnancy. Knowing the mother's immune status before or at the beginning of gestation can contribute, together with early diagnosis, to improve the management of patients at risk.