Early fetal anomaly scanning in a population at increased risk of abnormalities

First trimester examination of fetal anatomy: clinical practice guideline by the World Association of Perinatal Medicine (WAPM) and the Perinatal Medicine Foundation (PMF)

This recommendation document follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation. We aim to bring together groups and individuals throughout the world for precise standardization to implement the ultrasound evaluation of the fetus in the first trimester of pregnancy and improve the early detection of anomalies and the clinical management of the pregnancy. The aim is to present a document that includes statements and recommendations on the standard evaluation of the fetal anatomy in the first trimester, based on quality evidence in the peer-reviewed literature as well as the experience of perinatal experts around the world.

First-trimester ultrasound detection of fetal heart anomalies: systematic review and meta-analysis

OBJECTIVES

To determine the diagnostic accuracy of ultrasound at 11-14 weeks' gestation in the detection of fetal cardiac abnormalities and to evaluate factors that impact the detection rate.

METHODS

This was a systematic review of studies evaluating the diagnostic accuracy of ultrasound in the detection of fetal cardiac anomalies at 11-14 weeks' gestation, performed by two independent reviewers. An electronic search of four databases (MEDLINE, EMBASE, Web of Science Core Collection and The Cochrane Library) was conducted for studies published between January 1998 and July 2020. Prospective and retrospective studies evaluating pregnancies at any prior level of risk and in any healthcare setting were eligible for inclusion. The reference standard used was the detection of a cardiac abnormality on postnatal or postmortem examination. Data were extracted from the included studies to populate 2 × 2 tables. Meta-analysis was performed using a random-effects model in order to determine the performance of first-trimester ultrasound in the detection of major cardiac abnormalities overall and of individual types of cardiac abnormality. Data were analyzed separately for high-risk and non-high-risk populations. Preplanned secondary analyses were conducted in order to assess factors that may impact screening performance, including the imaging protocol used for cardiac assessment (including the use of color-flow Doppler), ultrasound modality, year of publication and the index of sonographer suspicion at the time of the scan. Risk of bias and quality assessment were undertaken for all included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.

RESULTS

The electronic search yielded 4108 citations. Following review of titles and abstracts, 223 publications underwent full-text review, of which 63 studies, reporting on 328 262 fetuses, were selected for inclusion in the meta-analysis. In the non-high-risk population (45 studies, 306 872 fetuses), 1445 major cardiac anomalies were identified (prevalence, 0.41% (95% CI, 0.39-0.43%)). Of these, 767 were detected on first-trimester ultrasound examination of the heart and 678 were not detected. First-trimester ultrasound had a pooled sensitivity of 55.80% (95% CI, 45.87-65.50%), specificity of 99.98% (95% CI, 99.97-99.99%) and positive predictive value of 94.85% (95% CI, 91.63-97.32%) in the non-high-risk population. The cases diagnosed in the first trimester represented 63.67% (95% CI, 54.35-72.49%) of all antenatally diagnosed major cardiac abnormalities in the non-high-risk population. In the high-risk population (18 studies, 21 390 fetuses), 480 major cardiac anomalies were identified (prevalence, 1.36% (95% CI, 1.20-1.52%)). Of these, 338 were detected on first-trimester ultrasound examination and 142 were not detected. First-trimester ultrasound had a pooled sensitivity of 67.74% (95% CI, 55.25-79.06%), specificity of 99.75% (95% CI, 99.47-99.92%) and positive predictive value of 94.22% (95% CI, 90.22-97.22%) in the high-risk population. The cases diagnosed in the first trimester represented 79.86% (95% CI, 69.89-88.25%) of all antenatally diagnosed major cardiac abnormalities in the high-risk population. The imaging protocol used for examination was found to have an important impact on screening performance in both populations (P < 0.0001), with a significantly higher detection rate observed in studies using at least one outflow-tract view or color-flow Doppler imaging (both P < 0.0001). Different types of cardiac anomaly were not equally amenable to detection on first-trimester ultrasound.

CONCLUSIONS

First-trimester ultrasound examination of the fetal heart allows identification of over half of fetuses affected by major cardiac pathology. Future first-trimester screening programs should follow structured anatomical assessment protocols and consider the introduction of outflow-tract views and color-flow Doppler imaging, as this would improve detection rates of fetal cardiac pathology. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

First trimester anomaly scan using virtual reality (VR FETUS study): study protocol for a randomized clinical trial

Background

In recent years it has become clear that fetal anomalies can already be detected at the end of the first trimester of pregnancy by two-dimensional (2D) ultrasound. This is why increasingly in developed countries the first trimester anomaly scan is being offered as part of standard care. We have developed a Virtual Reality (VR) approach to improve the diagnostic abilities of 2D ultrasound. Three-dimensional (3D) ultrasound datasets are used in VR assessment, enabling real depth perception and unique interaction. The aim of this study is to investigate whether first trimester 3D VR ultrasound is of additional value in terms of diagnostic accuracy for the detection of fetal anomalies. Health-related quality of life, cost-effectiveness and also the perspective of both patient and ultrasonographer on the 3D VR modality will be studied.

Methods

Women in the first trimester of a high risk pregnancy for a fetus with a congenital anomaly are eligible for inclusion. This is a randomized controlled trial with two intervention arms. The control group receives ‘care as usual’: a second trimester 2D advanced ultrasound examination. The intervention group will undergo an additional first trimester 2D and 3D VR ultrasound examination. Following each examination participants will fill in validated questionnaires evaluating their quality of life and healthcare related expenses. Participants’ and ultrasonographers’ perspectives on the 3D VR ultrasound will be surveyed. The primary outcome will be the detection of fetal anomalies. The additional first trimester 3D VR ultrasound examination will be compared to ‘care as usual’. Neonatal or histopathological examinations are considered the gold standard for the detection of congenital anomalies. To reach statistical significance and 80% power with a detection rate of 65% for second trimester ultrasound examination and 70% for the combined detection of first trimester 3D VR and second trimester ultrasound examination, a sample size of 2800 participants is needed.

Discussion

First trimester 3D VR detection of fetal anomalies may improve patients’ quality of life through reassurance or earlier identification of malformations. Results of this study will provide policymakers and healthcare professionals with the highest level of evidence for cost-effectiveness of first trimester ultrasound using a 3D VR approach.

Trial registration

Dutch Trial Registration number NTR6309, date of registration 26 January 2017.

First-Trimester Ultrasound

Since the 1980s, development of high-resolution transvaginal ultrasound transducers has significantly improved ultrasound evaluation at earlier gestational ages. Although many indications exist for first-trimester ultrasound in pregnancy, more emphasis has been placed on assessment of fetal anatomy recently. In turn, congenital diagnoses can also be made earlier in pregnancy, raising the question of whether anatomic assessment in the first trimester is one of choice or obligation. Combining transvaginal and transabdominal approach yields the highest detection rate overall. Some studies have shown that more than half of all anomalies and almost all severe anomalies can be detected on early scans.

Systematic review of first-trimester ultrasound screening for detection of fetal structural anomalies and factors that affect screening performance

OBJECTIVES

To determine the sensitivity and specificity of first-trimester ultrasound for the detection of fetal abnormalities and to establish which factors might impact on screening performance.

METHODS

A systematic review and meta-analysis of all relevant publications was performed to assess the diagnostic accuracy of two-dimensional transabdominal and transvaginal ultrasound in the detection of congenital fetal anomalies prior to 14 weeks' gestation. The reference standard was detection of abnormalities at birth or postmortem. Factors that may impact on detection rates were evaluated, including population characteristics, gestational age, healthcare setting, ultrasound modality, use of an anatomical checklist for detection of first-trimester anomalies and type of malformation included in the study. In an effort to reduce the impact of study heterogeneity on the results of the meta-analysis, data from the studies were analyzed within subgroups of major anomalies vs all types of anomaly and low-risk/unselected populations vs high-risk populations.

RESULTS

An electronic search (until 29 July 2015) identified 2225 relevant citations, from which a total of 30 studies, published between 1991 and 2014, were selected for inclusion. The pooled estimate for the detection of major abnormalities in low-risk or unselected populations (19 studies, 115 731 fetuses) was 46.10% (95% CI, 36.88-55.46%). The detection rate for all abnormalities in low-risk or unselected populations (14 studies, 97 976 fetuses) was 32.35% (95% CI, 22.45-43.12%), whereas in high-risk populations (six studies, 2841 fetuses) it was 61.18% (95% CI, 37.71-82.19%). Of the factors examined for their impact on detection rate, there was a statistically significant relationship (P < 0.0001) between the use of a standardized anatomical protocol during first-trimester anomaly screening and its sensitivity for the detection of fetal anomalies in all subgroups.

CONCLUSIONS

Detection rates of first-trimester fetal anomalies ranged from 32% in low-risk groups to more than 60% in high-risk groups, demonstrating that first-trimester ultrasound has the potential to identify a large proportion of fetuses affected with structural anomalies. The use of a standardized anatomical protocol improves the sensitivity of first-trimester ultrasound screening for all anomalies and major anomalies in populations of varying risk. The development and introduction of international protocols with standard anatomical views should be undertaken in order to optimize first-trimester anomaly detection. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

A structurally normal fetus at the 11- to 14-week ultrasound does not guarantee a newborn without congenital anomalies: a cohort study

OBJECTIVE

The objective of this study was to analyze the influence of maternal demographic characteristics and abnormal first-trimester sonographic markers on congenital anomalies (CAs) at birth when the fetus is structurally normal at the 11- to 14-week ultrasound.

METHODS

This prospective cohort study comprised high-risk women undergoing routine antenatal care. Detailed assessments of fetal anatomy and first-trimester sonographic markers were performed at 11-14 weeks of pregnancy. Multilevel regression analysis was used to determine the effects of maternal characteristics and abnormal first-trimester sonographic markers on the incidence of CA at birth.

RESULTS

Three hundred and ten patients were evaluated, and 41 patients (13.2%) had an anomalous newborn. The presence of a specific indication at the first-trimester ultrasound (OR: 2.72; CI 95% 1.09-6.74) or a nuchal translucency (NT) thickness greater than 2.5 mm increased the risk of CA at birth by three fold (OR: 3.10; CI 95% 1.07-9.59). High adjusted risks for trisomies 21, 18 and 13 increased the likelihood of having a structurally abnormal newborn by five, twelve and six fold, respectively.

CONCLUSION

Increased NT and/or high adjusted risks for trisomies 21, 18, and 13 increase the risk of CA at birth, even in fetuses with a structurally normal 11- to 14-week ultrasound scan.

Fetal imaging: executive summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging (MRI) in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and MRI in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost effectiveness, and to identify research opportunities. This article is the executive summary of the workshop.

Advances in ultrasound imaging for congenital malformations during early gestation

BACKGROUND

With refinement in ultrasound technology, detection of fetal structural abnormalities has improved and there have been detailed reports of the natural history and expected outcomes for many anomalies. The ability to either reassure a high-risk woman with normal intrauterine images or offer comprehensive counseling and offer options in cases of strongly suspected lethal or major malformations has shifted prenatal diagnoses to the earliest possible gestational age.

METHODS

When indicated, scans in early gestation are valuable in accurate gestational dating. Stricter sonographic criteria for early nonviability guard against unnecessary intervention. Most birth defects are without known risk factors, and detection of certain malformations is possible in the late first trimester.

RESULTS

The best time for a standard complete fetal and placental scan is 18 to 20 weeks. In addition, certain soft anatomic markers provide clues to chromosomal aneuploidy risk. Maternal obesity and multifetal pregnancies are now more common and further limit early gestation visibility.

CONCLUSION

Other advanced imaging techniques during early gestation in select cases of suspected malformations include fetal echocardiography and magnetic resonance imaging.

Ultrasound evaluation of the first trimester

Ultrasound is a valuable diagnostic test throughout the first trimester of pregnancy. Early in this trimester, it is used to distinguish between normal intrauterine, failed intrauterine, and ectopic pregnancies. Later it can be used with maternal blood tests to screen for trisomy 21 and other forms of aneuploidy, and in some centers to assess fetal anatomy and diagnose structural anomalies. First trimester sonography is also useful for accurate assessment of gestational age. This article reviews these applications, the approach to establishing diagnoses, and ways to avoid diagnostic mistakes that can lead to serious errors in patient management and adverse pregnancy outcome.

Fetal imaging: Executive summary of a Joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and magnetic resonance imaging in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost-effectiveness and to identify research opportunities. This article is the executive summary of the workshop.

Fetal imaging: executive summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop

Given that practice variation exists in the frequency and performance of ultrasound and magnetic resonance imaging (MRI) in pregnancy, the Eunice Kennedy Shriver National Institute of Child Health and Human Development hosted a workshop to address indications for ultrasound and MRI in pregnancy, to discuss when and how often these studies should be performed, to consider recommendations for optimizing yield and cost effectiveness, and to identify research opportunities. This article is the executive summary of the workshop.

Should the first trimester ultrasound include anatomy survey?

First trimester scanning has become routine since the introduction of nuchal translucency screening. While most scans have included dating and gross anatomical structures, recent reports have shown that with improvement of ultrasound technology, especially high-frequency transvaginal transducers, detailed analysis of the early fetal anatomy is now possible. Studies included in this manuscript demonstrate the ability to now being able to identify many fetal malformations including some very subtle ones. The literature presented has carefully conducted many prospective studies presenting timelines that show optimal periods to review the anatomical structures by a given gestational age especially noting when these anatomical structures are not optimally seen.

[Asphyxiating thoracic dysplasia (Jeune syndrome): about two cases]

Asphyxiating thoracic dysplasia (Jeune syndrome) is an osteochondrodysplasia with autosomal recessive inheritance, characterised by a nanism with rhizomelic predominance, associated with a narrow thorax. It induces an alteration of the respiratory function that conditions the prognosis, which is worsened in case of associated visceral lesions (probably related to mutations of genes implicated in ciliary development, as recently described). We report the observation of two severe cases of Jeune syndrome to emphasize the advancement of imaging, especially echography, and molecular biology in establishing prenatal diagnosis as well as prognosis of this syndrome.

Performing a fetal anatomy scan at the time of first-trimester screening

Over the past decade, prenatal diagnosis has shifted rapidly from the second trimester into the first trimester. Although the nuchal-translucency scan may detect a small proportion of fetal structural malformations, fetal anatomy is not routinely assessed until the fetal anatomical survey is performed in the second trimester between 18 and 22 weeks. The recent development of high-frequency transvaginal ultrasound transducers has led to vastly improved ultrasound resolution and improved visualization of fetal anatomy earlier in gestation. Several pilot studies of a first-trimester anatomic survey have reported detection rates comparable with those achieved in the routine second-trimester anatomic survey. As advanced ultrasound technology becomes more available, there is an urgent need to evaluate the diagnostic ability of a first-trimester anatomic survey and to determine the role of a first-trimester anatomic survey in the current screening paradigm.

Prenatal imaging: ultrasonography and magnetic resonance imaging

The Eunice Kennedy Shriver National Institute of Child Health and Human Development held a workshop on September 18-19, 2006, to summarize the available evidence on the role and performance of current fetal imaging technology and to establish a research agenda. Ultrasonography is the imaging modality of choice for pregnancy evaluation due to its relatively low cost, real-time capability, safety, and operator comfort and experience. First-trimester ultrasonography extends the available window for fetal observation and raises the possibility of performing an early anatomic survey. Three-dimensional ultrasonography has the potential to expand the clinical application of ultrasonography by permitting local acquisition of volumes and remote review and interpretation at specialized centers. New advances allow performance of fetal magnetic resonance imaging (MRI) without maternal or fetal sedation, with improved characterization and prediction of prognosis of certain fetal central nervous system anomalies such as ventriculomegaly when compared with ultrasonography. Fewer data exist on the usefulness of fetal MRI for non-central nervous system anomalies.

Profile of major congenital malformations at Nizwa Hospital, Oman: 10-year review

OBJECTIVE

The objective of this study was to establish the profile of major congenital malformations at Nizwa Hospital, which is a major hospital in the Al-Dakhliya region of Oman.

METHODS

All births with birthweight more than 500 g were prospectively studied from January 1993 through December 2002 for a period of 10 years. A congenital anomaly register was maintained in the special care baby unit (SCBU) and details of each case were recorded after parents' interviews, clinical evaluation and relevant radiological and laboratory investigations. The major malformations were classified as multiple or single-system abnormalities as well as genetic or non-genetic disorders.

RESULTS

Of the 21 988 births during the study period, 541 babies (24.6 per 1000 births) had major malformations. Of the 541 babies, 158 (29.2%) had multiple malformations and 335 (61.9%) had involvement of a single system. In 48 (8.9%) babies a complete evaluation was not possible. Of the cases with multiple abnormalities, 57 had recognized syndromes, of which 28 (49.1%) were autosomal recessive disorders. Seventy (12.9%) cases had chromosomal abnormalities. The most common systems involved in neonates with single-system malformations were the gastrointestinal system (100 cases), the central nervous system (79 cases) and the cardiovascular system (63 cases). Although the consanguinity rate of 53.1% among Omani births almost matched with the regional average of 52.7%, it was 76% among those with major malformations. Also, there was an increased clustering of multiple abnormalities and rare recessive disorders in cases with closely related parents and grandparents. The birth prevalence of major malformations was 14.6 per 1000 in non-Omani births as compared to 25.2 in Omani births (P < 0.05). Genetic factors could be implicated in 343 (63.4%) cases and 130 (37.9%) of these were potentially preventable.

CONCLUSION

Genetic disorders account for a significant proportion of congenital malformations in Oman.

Qualified and trained sonographers in the US can perform early fetal anatomy scans between 11 and 14 weeks

OBJECTIVES

The objective of this study was to determine the extent to which normal fetal anatomy can be detected between 11- and 14-week scan by sonographers in the US.

STUDY DESIGN

In a prospective cross-sectional study, 223 unselected women underwent a detailed assessment of fetal anatomy at 11 to 13 and 6/7 weeks by sonographers with transabdominal and/or transvaginal transducers. Thirty-seven structures were examined. Two groups were identified: group I: 121 patients between 11 and 12 weeks, and group II: 102 patients between 13 and 14 weeks.

RESULTS

Structures other than the posterior fossa, heart, genitalia, and the sacral spine were seen between 64% to 99% for group I, and 72% to 98% for group II. The following structures were detected with statistically significantly higher rates in group II compared with group I: cerebellum, posterior fossa, face, 4-chamber view left ventricular outflow tract, aortic arch, ductal arch, kidneys, and genitalia. Comparing the patients of group I and group II, the transvaginal scans yielded a higher detection rate of structures than do the transabdominal scans.

CONCLUSION

Anatomic surveys between 11 and 14 weeks can be performed by sonographers with good detection rates of most structures. Using the vaginal probe compared with the abdominal probe improved the detection rate at 13 to 14 weeks as well as 11 to 12 weeks. If early fetal structure evaluation is to become customary in the US, the present practice of experienced and trained sonographers to scan such patients can be maintained.

Invasive fetal testing

PURPOSE OF REVIEW

Research on prenatal diagnosis and invasive fetal testing has continued at a rapid pace. Several studies that will have a profound impact on the way prenatal care will be provided to pregnant women have been published in the literature during the last year. These publications will be reviewed and their impact described.

RECENT FINDINGS

The main areas of interest in the recent literature covered in this review are first-trimester screening for aneuploidy, recent information on loss rates due to amniocentesis and chorionic villus sampling, and current work on invasive fetal therapy.

SUMMARY

It appears that first-trimester screening is at least comparable if not superior in efficacy to second-trimester serum screening. This will be a test that will be utilized increasingly by both low and high-risk patients for aneuploidy. Of utility to a much smaller number of patients, invasive fetal therapy for meningomyelocele repair, twin-to-twin transfusion syndrome and fetal cardiac malformations is being evaluated in a scientifically more rigorous manner.

First trimester anatomy scan: pushing the limits. What can we see now?

PURPOSE OF REVIEW

The aim of this review article is to familiarize the reader with the current developments dealing with ultrasound during the first trimester of pregnancy.

RECENT FINDINGS

The main emphasis of this article is to review the anatomy seen during the first trimester and to bring to the reader the fact that the first anatomical survey of the fetus does not have to wait until the 18th to 20th week of gestation. The fetus can be surveyed adequately as early as the 12th week of gestation and ideally between the 13th and 14th weeks. Of course, not all malformations will be detected during the first trimester, and a follow-up scan between 20 and 23 weeks is indicated.

SUMMARY

The ongoing improvements in ultrasound technology allow us to see more details of the embryo or fetus at earlier gestational ages than ever before. This is resulting in a rethinking of when the first anatomical survey should be performed.