Sonographic detection of fetal abnormalities before 11 weeks of gestation

Ultrasound Screening in the First and Second Trimester of Pregnancy for the Detection of Fetal Cardiac Anomalies in a Low-Risk Population

Background/Objectives: Congenital heart disease (CHD) is the most common birth defect, an important cause of morbidity and mortality, with a reported prevalence of 5-12 per 1000 live births. The aim of our study was to identify the role of fetal morphological ultrasound examination in the first and second trimester of pregnancy in the detection of fetal congenital cardiac anomalies in a low-risk population. Methods: We performed a retrospective study in a tertiary fetal medicine center in Emergency Hospital Craiova, Romania. The longitudinal analysis combined first- and second-trimester screening using improved ultrasound protocols. Our study evaluated 8944 pregnant women with singleton pregnancies in a 6-year period between January 2018 and December 2023. All ultrasound examinations were performed using a standard extended protocol according to the main guidelines' recommendations for the detection of fetal anomalies. Results: In the first trimester of pregnancy, 37 cases with cardiac anomalies were diagnosed. Thirteen of these cases were associated with genetic anomalies (Down syndrome-eight cases, Edwards syndrome-four cases, Turner syndrome-one case). Some of these pregnancies were associated with at least one of the minor ultrasound markers (inverted ductus venosus, abnormal flow in the tricuspid valve, presence of choroid plexus cysts, absent/hypoplastic nasal bone). In the second trimester of pregnancy, 17 cases of cardiac anomalies were diagnosed. From these cases, one was associated with genetic anomalies (DiGeorge Syndrome), and one case developed hydrops and delivered prematurely in the early third trimester. Conclusions: Ultrasound screening for the detection of congenital heart disease is feasible early in pregnancy, but some anomalies would be obvious later in pregnancy. An early diagnosis using an extended ultrasound protocol, genetic testing, and a multidisciplinary evaluation would improve the prognosis and the overall survival rate by delivering in a tertiary center that allows for rapid cardiac surgery in dedicated cases.

Fetal Phenotyping and Whole Exome Sequencing for 12 Egyptian Families With Serine Biosynthesis Defect: Novel Clinical and Allelic Findings With a Founder Effect

OBJECTIVE

The purpose of this study was to improve our understanding of severe serine biosynthesis defects through a comprehensive description of prenatal, and postnatal manifestations and the mutational spectrum in a new cohort of 12 unrelated Egyptian Families.

METHODS

Detailed fetal ultrasound examination, postnatal assessment, and whole exome sequencing (WES) were performed in a cohort of 12 fetuses with suspected Neu-Laxova syndrome (NLS), the most severe expression of serine biosynthesis defects. Additionally, a comprehensive review of the literature was conducted by merging the data from all the molecularly-confirmed cases with ours to gain a better understanding of the clinical variability of NLS.

RESULTS

Novel clinical manifestations including intrauterine convulsions, hemivertebrae, natal teeth, holoprosencephaly, and rhombencephalosynapsis were observed. Molecular analysis identified 7 and 2 likely disease-causing variants in the PSAT1 and PHGDH genes, respectively. Four of them were novel, including the c.734G>A missense variant in PSAT1, which has been proposed to be a founder variant among Egyptians.

CONCLUSION

The present cohort expands the spectrum of serine biosynthesis disorders. Moreover, it illuminates the role of prenatal exome sequencing in lethal conditions constituting the most severe end of already-known human diseases.

Antenatal screening for fetal structural anomalies - Routine or targeted practice?

Antenatal screening with ultrasound identifies fetal structural anomalies in 3-6% of pregnancies. Identification of anomalies during pregnancy provides an opportunity for counselling, targeted imaging, genetic testing, fetal intervention and delivery planning. Ultrasound is the primary modality for imaging the fetus in pregnancy, but magnetic resonance imaging (MRI) is evolving as an adjunctive tool providing additional structural and functional information. Screening should start from the first trimester when more than 50% of severe defects can be detected. The mid-trimester ultrasound balances the benefits of increased fetal growth and development to improve detection rates, whilst still providing timely management options. A routine third trimester ultrasound may detect acquired anomalies or those missed earlier in pregnancy but may not be available in all settings. Targeted imaging by fetal medicine experts improves detection in high-risk pregnancies or when an anomaly has been detected, allowing accurate phenotyping, access to advanced genetic testing and expert counselling.

Research progress on ultrasound and molecular markers for prenatal diagnosis of neural tube defects

Neural tube defects (NTDs) are severe congenital anomalies that result from the failure of early neural tube closure during fetal neurogenesis. They are the most common and severe congenital malformations of the central nervous system. Identifying reliable prenatal diagnostic ultrasound and molecular markers that can predict NTDs is of paramount importance. Early diagnosis of NTDs allows embryonic treatment and prevention strategies, which are crucial for reducing the disability rate associated with these malformations, reducing the burden on individuals and on society. The purpose of this comprehensive review was to summarize the ultrasound biomarkers between 11 and 13 weeks of gestation and the molecular biomarkers used in the diagnosis of NTDs, providing additional insights into early screening for NTDs.

Current controversies in prenatal diagnosis: Noninvasive prenatal testing should replace other screening strategies for fetal trisomies 13, 18, 21

This is a written summary of the oral debate presented at the International Society for Prenatal Diagnosis annual conference in Edinburgh in 2023. The topic under debate is whether noninvasive prenatal testing (NIPT) using cell-free fetal DNA should replace other screening strategies for the detection of fetal trisomies 13, 18, 21. There is no disagreement that NIPT is far more sensitive and has better positive predictive values for identifying trisomies 13, 18, and 21 than traditional screening approaches using biochemical markers and measurement of nuchal translucency. The major issue lies in the potential adverse consequences associated with abandoning traditional screening methods. The source of disagreement stems primarily from whether you consider the role of ultrasound in the context of screening to be strictly for nuchal translucency measurement or whether it should be combined with a fetal anatomy scan. The debate featured two experts who presented evidence in favor of each argument.

Ultrasound findings and detection of fetal abnormalities before 11 weeks of gestation

OBJECTIVE

To determine the proportion of major fetal structural abnormalities that can be detected before 11 gestational weeks.

METHODS

We conducted a retrospective study of individual patient files at a tertiary provider of obstetric and gynecological ultrasound in Melbourne, Australia. All women who had a pre-cell-free DNA ultrasound with a crown-rump length of less than 45 mm and had one or more ultrasounds at a later gestation were included in the analysis. The primary outcome was the incidence of a fetal structural abnormality.

RESULTS

A total of 3333 cases were included in the final analysis. Overall, 316 fetuses (9.5%) had a structural abnormality detected at any point throughout gestation, of which 86 were major structural abnormalities (2.6%). Sixteen fetal abnormalities were detected before 11 weeks of gestation, including 15 major abnormalities (17.4% of the major anomalies). All major fetal abnormalities detected before 11 gestational weeks were confirmed at later ultrasound examinations or the pregnancy did not continue (in four cases due to termination of pregnancy and in one case spontaneous miscarriage before first trimester morphology ultrasound).

CONCLUSION

Detection of fetal abnormalities is possible before 11 weeks of gestation. Early suspicion is more likely in cases of major structural abnormalities.

A missing kidney and a hidden congenital diaphragmatic hernia

Congenital intrathoracic kidney (ITK) is a rare condition, which is usually discovered incidentally in asymptomatic children who do not need any intervention. However, it may be associated with congenital diaphragmatic hernia (CDH), in which case it requires urgent surgical intervention. We present a case of prenatally diagnosed ITK associated with a left CDH that was operated on day 5 of life. The neonate is currently well at 15 months of age.

The importance of ultrasound preceding cell-free DNA screening for fetal chromosomal abnormalities

OBJECTIVE

This study aims to determine the incidence of ultrasound findings that may change clinical management on the day of blood-sampling for cell-free DNA (cfDNA) screening.

METHODS

A retrospective study was conducted at a tertiary provider of obstetric and gynecological ultrasound in Melbourne, Australia. Individual patient files were reviewed and results were collated for maternal characteristics, pre-cfDNA ultrasound reports, results and test characteristics of both cfDNA and diagnostic testing, and genetic counselling notes. The primary outcome was a potential change in patient management due to findings detected on the pre-cfDNA ultrasound.

RESULTS

Of 6250 pre-cfDNA ultrasounds, 6207 were included in analysis. Of these, 598 (9.6%) pregnancies had a finding on pre-cfDNA ultrasound that had the potential to change management. The reasons for this potential change in management were detection of gestational age below 10 weeks (245, 3.9%), miscarriage (175, 2.8%), demised twin (43, 0.7%), fetal edema (115, 1.9%) and major structural abnormalities (20, 0.3%). These findings were more common in patients of advanced maternal age and in spontaneous conceptions.

CONCLUSIONS

An ultrasound prior to cfDNA screening has the potential to change clinical management in almost one in 10 women. The proportion is higher in older age groups and lower in IVF-conceived pregnancies.