First-trimester detection of structural abnormalities and the role of aneuploidy markers

Diagnostic accuracy of ultrasound screening for fetal structural abnormalities during the first and second trimester of pregnancy in low-risk and unselected populations

BACKGROUND

Prenatal ultrasound is widely used to screen for structural anomalies before birth. While this is traditionally done in the second trimester, there is an increasing use of first-trimester ultrasound for early detection of lethal and certain severe structural anomalies.

OBJECTIVES

To evaluate the diagnostic accuracy of ultrasound in detecting fetal structural anomalies before 14 and 24 weeks' gestation in low-risk and unselected pregnant women and to compare the current two main prenatal screening approaches: a single second-trimester scan (single-stage screening) and a first- and second-trimester scan combined (two-stage screening) in terms of anomaly detection before 24 weeks' gestation.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded (Web of Science), Social Sciences Citation Index (Web of Science), Arts & Humanities Citation Index and Emerging Sources Citation Index (Web of Science) from 1 January 1997 to 22 July 2022. We limited our search to studies published after 1997 and excluded animal studies, reviews and case reports. No further restrictions were applied. We also screened reference lists and citing articles of each of the included studies.

SELECTION CRITERIA

Studies were eligible if they included low-risk or unselected pregnant women undergoing a first- and/or second-trimester fetal anomaly scan, conducted at 11 to 14 or 18 to 24 weeks' gestation, respectively. The reference standard was detection of anomalies at birth or postmortem.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook study selection, quality assessment (QUADAS-2), data extraction and evaluation of the certainty of evidence (GRADE approach). We used univariate random-effects logistic regression models for the meta-analysis of sensitivity and specificity.

MAIN RESULTS

Eighty-seven studies covering 7,057,859 fetuses (including 25,202 with structural anomalies) were included. No study was deemed low risk across all QUADAS-2 domains. Main methodological concerns included risk of bias in the reference standard domain and risk of partial verification. Applicability concerns were common in studies evaluating first-trimester scans and two-stage screening in terms of patient selection due to frequent recruitment from single tertiary centres without exclusion of referrals. We reported ultrasound accuracy for fetal structural anomalies overall, by severity, affected organ system and for 46 specific anomalies. Detection rates varied widely across categories, with the highest estimates of sensitivity for thoracic and abdominal wall anomalies and the lowest for gastrointestinal anomalies across all tests. The summary sensitivity of a first-trimester scan was 37.5% for detection of structural anomalies overall (95% confidence interval (CI) 31.1 to 44.3; low-certainty evidence) and 91.3% for lethal anomalies (95% CI 83.9 to 95.5; moderate-certainty evidence), with an overall specificity of 99.9% (95% CI 99.9 to 100; low-certainty evidence). Two-stage screening had a combined sensitivity of 83.8% (95% CI 74.7 to 90.1; low-certainty evidence), while single-stage screening had a sensitivity of 50.5% (95% CI 38.5 to 62.4; very low-certainty evidence). The specificity of two-stage screening was 99.9% (95% CI 99.7 to 100; low-certainty evidence) and for single-stage screening, it was 99.8% (95% CI 99.2 to 100; moderate-certainty evidence). Indirect comparisons suggested superiority of two-stage screening across all analyses regarding sensitivity, with no significant difference in specificity. However, the certainty of the evidence is very low due to the absence of direct comparisons.

AUTHORS' CONCLUSIONS

A first-trimester scan has the potential to detect lethal and certain severe anomalies with high accuracy before 14 weeks' gestation, despite its limited overall sensitivity. Conversely, two-stage screening shows high accuracy in detecting most fetal structural anomalies before 24 weeks' gestation with high sensitivity and specificity. In a hypothetical cohort of 100,000 fetuses, the first-trimester scan is expected to correctly identify 113 out of 124 fetuses with lethal anomalies (91.3%) and 665 out of 1776 fetuses with any anomaly (37.5%). However, 79 false-positive diagnoses are anticipated among 98,224 fetuses (0.08%). Two-stage screening is expected to correctly identify 1448 out of 1776 cases of structural anomalies overall (83.8%), with 118 false positives (0.1%). In contrast, single-stage screening is expected to correctly identify 896 out of 1776 cases before 24 weeks' gestation (50.5%), with 205 false-positive diagnoses (0.2%). This represents a difference of 592 fewer correct identifications and 88 more false positives compared to two-stage screening. However, it is crucial to acknowledge the uncertainty surrounding the additional benefits of two-stage versus single-stage screening, as there are no studies directly comparing them. Moreover, the evidence supporting the accuracy of first-trimester ultrasound and two-stage screening approaches primarily originates from studies conducted in single tertiary care facilities, which restricts the generalisability of the results of this meta-analysis to the broader population.

First Trimester Ultrasound Detection of Fetal Central Nervous System Anomalies

OBJECTIVE

To evaluate the potential of the first-trimester ultrasound (US) features for the detection of central nervous system (CNS) anomalies. Methods/Methodology: This is a prospective one-center three-year study. Unselected singleton pregnant women were examined using an extended first-trimester anomaly scan (FTAS) that included the CNS assessment: the calvaria shape, the septum (falx cerebri), the aspect of the lateral ventricles, the presence of the third ventricle and aqueduct of Sylvius (AS) and the posterior brain morphometry: the fourth ventricle, namely intracranial translucency (IT), brain stem/brain stem-occipital bone ratio (BS/BSOB) and cisterna magna (CM). The spine and underlying skin were also evaluated. The cases were also followed during the second and third trimesters of pregnancy and at delivery. FTAS efficiency to detect major CNS abnormalities was calculated.

RESULTS

We detected 17 cases with CNS major abnormalities in a population of 1943 first-trimester (FT) fetuses, including spina bifida with myelomeningocele, exencephaly-anencephaly, holoprosencephaly, hydrocephaly, cephalocele and Dandy-Walker malformation. The CNS features in the abnormal group are presented. In the second trimester (ST), we further diagnosed cases of corpus callosum agenesis, cerebellar hypoplasia, vein of Galen aneurysm and fetal infection features (ventriculomegaly, intraventricular bands, intraventricular cyst and hyperechoic foci), all declared normal at the FTAS. During the third trimester (TT) scan we identified a massive fetal cerebral haemorrhage absent at previous investigations. We report a detection rate of 72.7% of fetal brain anomalies in the FT using the proposed CNS parameters. The sensitivity of the examination protocol was 72.7%, and the specificity was 100%.

CONCLUSION

A detailed FT CNS scan is feasible and efficient. The majority of cases of major CNS abnormalities can be detected early in pregnancy. The visualization rates of the CNS parameters in the FT are great with short, if any, additional investigation time. FT cerebral disorders such as haemorrhage or infections were missed in the FT even when an extended evaluation protocol was used.

Presentation of ventriculomegaly at 11-14 weeks of gestation: An analysis of longitudinal data

OBJECTIVES

The aim of this study was to examine the value of the sonographic measurements of the choroid plexus and the lateral ventricles at 11-14 gestational weeks in fetuses that had the diagnosis of second-trimester ventriculomegaly (VM) as a clinical reference.

METHODS

The standard axial plane used for biparietal diameter measurement from 2D stored images in the first trimester was used to calculate the ratio between the choroid plexus and lateral ventricle diameter (PDVDR), the choroid plexus and lateral ventricle length (PLVLR) and the choroid plexus and lateral ventricle area (PAVAR) in 100 normal and 15 fetuses diagnosed with second-trimester VM.

RESULTS

In fetuses with VM, the measurements of PDVDR, PLVLR and PAVAR were all significantly smaller compared to normal fetuses (p = < 0.001, <0.001, <0.01). Four out of seven cases with mild VM had measurements below the 5th percentile (57%). 75% of cases with moderate or severe VM had at least one measurement below the 5th percentile.

CONCLUSIONS

Since the axial plane of the fetal head is obtained in all first-trimester routine screenings, the measurements of PDVDR, PLVLR and PAVAR could easily be integrated into routine examinations for an early detection of VM.

Prenatal diagnosis and pregnancy outcome of major structural anomalies detectable in the first trimester: A population-based cohort study in the Netherlands

BACKGROUND

Prenatal diagnosis of several major congenital anomalies can be achieved in the first trimester of pregnancy.

OBJECTIVE

This study investigates the timing of diagnosis and pregnancy outcome of foetuses and neonates with selected structural anomalies in the Northern Netherlands over a 10-year period when the prenatal screening programme changed significantly, but no first-trimester anatomical screening was implemented.

METHODS

We performed a population-based retrospective cohort study with data from the EUROCAT Northern Netherlands database on pregnancies with delivery or termination of pregnancy for fetal anomaly (TOPFA) date between 2010 and 2019. The analysis was restricted to anomalies potentially detectable in the first trimester of pregnancy in at least 50% of cases, based on previously published data. These included: anencephaly, encephalocele, spina bifida, holoprosencephaly, tricuspid/pulmonary valve atresia, hypoplastic left heart, abdominal wall and limb reduction defects, lethal skeletal dysplasia, megacystis, multiple congenital anomalies. The primary outcome was the timing of diagnosis of each structural anomaly. Information on additional investigations, genetic testing and pregnancy outcome (live birth, TOPFA and foetal/neonatal death) was also collected.

RESULTS

A total of 478 foetuses were included; 95.0% (n = 454) of anomalies were detected prenatally and 5.0% (n = 24) postpartum. Among the prenatally detected cases, 31% (n = 141) were diagnosed before 14 weeks of gestation, 65.6% (n = 298) between 14-22 weeks and 3.3% (n = 15) after 22 weeks. Prenatal genetic testing was performed in 80.4% (n = 365) of cases with prenatally diagnosed anomalies, and the results were abnormal in 26% (n = 95). Twenty-one% (n = 102) of pregnancies resulted in live births and 62.8% (n = 300) in TOPFA. Spontaneous death occurred in 15.9% (n = 76) of cases: in-utero (6.1%, n = 29), at delivery (7.7%, n = 37) or in neonatal life (2.1%, n = 10).

CONCLUSION

Major structural anomalies amenable to early diagnosis in the first trimester of pregnancy are mostly diagnosed during the second trimester in the absence of a regulated first-trimester anatomical screening programme in the Netherlands and are associated with TOPFA and spontaneous death, especially in cases with underlying genetic anomalies.

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.

Timing of diagnosis of fetal structural abnormalities after the introduction of universal cell-free DNA in the absence of first-trimester anatomical screening

Introduction

Since 2021, first‐trimester anatomical screening (FTAS) is offered in the Netherlands alongside genome‐wide cell‐free DNA (cfDNA). Previously, only second‐trimester anatomical screening (STAS) was offered. This study identifies structural abnormalities amenable to first‐trimester diagnosis detected at/after STAS in the period following cfDNA implementation and preceding FTAS introduction.

Methods

This retrospective cohort includes 547 fetuses referred between 2017 and 2020 because of suspected structural abnormalities before/at/after STAS. Additional prenatal investigations and postnatal follow‐up were searched. Abnormalities were classified into “always”, “sometimes”, and “never” detectable in the first‐trimester based on a previously suggested classification.

Results

Of the 547 pregnancies, 13 (2.6%) received FTAS and 534 (97.6%) received a dating ultrasound and STAS. In 492/534 (92.1%) anomalies were confirmed; 66 (13.4%) belonged to the “always detectable” group in the first trimester, 303 (61.6%) to the “sometimes detectable”, and 123 (25.0%) to the never detectable. Of the “always detectable” anomalies 29/66 (44%) were diagnosed during dating ultrasounds and 37 (56%) during STAS. The rate of termination of pregnancy for anomalies detected during FTAS and at/after STAS was 84.6% (n = 11/13) and 29.3% (n = 144/492) (p < 0.01).

Conclusion

When FTAS is not part of screening paradigms, most fetal anomalies remain undetected until the second trimester or later in pregnancy, including 56% of anomalies “always detectable” in the first trimester.

What's already known about this topic?

About one‐third of all prenatally detectable fetal congenital abnormalities can be diagnosed in the first trimester of pregnancy. Especially major and lethal defects are amenable to early diagnosis.

What does this study add?

This study shows the evident delay in the timing of diagnosis of fetal structural abnormalities when first‐trimester anatomical screening (FTAS) is not routinely offered. The findings of this study strongly support the implementation of a regulated FTAS program in addition to universal screening by cell‐free DNA.

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.

Effect of prenatal screening on trends in perinatal mortality associated with congenital anomalies before and after the introduction of prenatal screening: A population-based study in the Northern Netherlands

BACKGROUND

Perinatal mortality in foetuses/children with congenital anomalies remains high. Prenatal diagnosis, essential for risk assessment and organisation of perinatal/postnatal care, offers parents the opportunity to consider the termination of pregnancy. In times of quick changes in prenatal screening programmes, it is relevant to evaluate the effect of prenatal screening on perinatal mortality rates.

OBJECTIVES

The objective of this study was to study trends in early foetal and perinatal mortality associated with congenital anomalies before/after the introduction of the Dutch prenatal screening programme.

METHODS

This population-based cohort study included 8535 foetuses/neonates with congenital anomalies born in the Northern Netherlands between 2001 and 2017. Total deaths were defined as sum of early foetal (before 24 weeks' gestation) and perinatal deaths (from 24 weeks' gestation till day 7 post-partum). Foetal deaths were categorised into spontaneous or elective termination of pregnancy for foetal anomalies (TOPFA). Trends in total mortality as well as early foetal and perinatal mortality were studied. Joinpoint regression was used to calculate the average annual percentage chance (AAPC) and identify linear trends in mortality within subperiods.

RESULTS

Total and perinatal mortality were 17% and 4%. Total mortality was higher in abnormal karyotype and central nervous system anomalies. We observed an increase in total mortality over time: 11.9% in 2001 versus 21.9% in 2017 (AAPC 2.6, 95% confidence interval [CI] 1.5, 3.7), caused by an increase in early foetal mortality from 5.5% to 19.2% (AAPC 8.7, 95% CI 4.7, 12.9) and a decrease in perinatal mortality from 6.4% to 2.7% (AAPC -5.6, 95% CI -10.0, -1.0). The increase in early foetal mortality reflects an increase in TOPFA from 3.6% to 16.9% (AAPC 8.3, 95% CI 4.2, 12.7), mostly occurring at 13-14 and 20-23 weeks' gestation.

CONCLUSIONS

The introduction of the prenatal screening programme led to a decrease in perinatal mortality among foetuses and neonates with congenital anomalies and a marked increase in early foetal mortality before 24 weeks' gestation due to higher rates of TOPFA.

The importance of first trimester screening of cranial posterior fossa in predicting posterior fossa malformations which may be identified in the following weeks of gestation

PURPOSE

We aimed to investigate the value of posterior fossa ultrasonography measurements in predicting fetal posterior fossa anomaly at 11-14 weeks of gestation.

METHODS

The study was performed at Zeynep Kamil Women and Children's Diseases Training and Research Hospital. Measurements were made in two groups: the control group consisted of 328 fetuses with normal postnatal outcome and the study group consisted of 22 fetuses with enlarged 4^th ventricle. In the study group, we questioned the value of intracranial translucency (IT) and brainstem (BS) measurements and the BS/brainstem-to-occipital bone (BSOB) ratio in order to predict possible posterior fossa anomalies that may be identified in advanced gestational weeks. The differences of ultrasonographic measurements between groups with p < 0.05 were considered statistically significant.

RESULTS

IT value, BSOB value, and BS/BSOB ratio were determined as ultrasonographic variables in predicting normal development of the fetal posterior fossa, with cutoff values of 2.7, 5.1, and 0.3. Negative predictive values of these three measurements for posterior fossa abnormalities were 100%. There was no statistically significant difference between the three variables for other diagnostic accuracy values (specifities and positive predictive values) (p > 0.05).

CONCLUSION

IT, BSOB, and BS/BSOB ratio can be used as ultrasonographic markers to predict the normal development of the fetal posterior fossa.

Perinatal outcome after selective termination in dichorionic twins discordant for congenital anomalies

INTRODUCTION

Our objective was to evaluate the perinatal outcome of selective termination of dichorionic twin pregnancies with discordant anomalies, according to gestational age at time of procedure.

MATERIAL AND METHODS

Retrospective review of 147 dichorionic twin pregnancies referred to our Fetal Medicine Unit between 2003 and 2018 for selective termination. Gestational age at delivery, fetal loss, and overall and 28-day post-delivery survival rates, were evaluated according to gestational age at time of procedure. Selective termination procedure was defined as early, intermediate, and late when performed before 18 weeks, between 18 and 23 weeks, and after 23 weeks, respectively. Kruskal-Wallis and chi-squared test were used to compare groups.

RESULTS

Overall survival at 28 days post-delivery, pregnancy loss, and preterm delivery before 32 weeks of gestation rates were 93.4%, 6.9%, and 15.5%, respectively. When stratified by gestational age at procedure, intermediate selective termination was associated with a lower survival rate than early and late procedures (86% vs. 96.9% and 100%, respectively; p = 0.035), and a nonsignificant trend for higher pregnancy loss (12% vs. 3.1%). Preterm delivery before 32 weeks of gestation occurred in 27% of late procedures, which was significantly higher than in early (9.5%) and intermediate (18.2%) procedures.

CONCLUSIONS

Selective termination in dichorionic twin pregnancies with discordant fetal anomaly is associated with low pregnancy loss and preterm delivery rate, primarily when performed before 18 weeks. When legally possible, late procedures can be a good alternative, particularly in those cases diagnosed beyond the 18th week of gestation.

Increased nuchal translucency after low-risk noninvasive prenatal testing: What should we tell prospective parents?

Three decades ago, the observation that first trimester fetuses with excess fluid accumulation at the back of the neck were more likely to be aneuploid, gave rise to a new era of prenatal screening. The nuchal translucency (NT) measurement in combination with serum biomarkers and maternal age, resulted in the first trimester combined screening (FTCS) program. The introduction of noninvasive prenatal testing (NIPT) over the past decade has introduced the option for parents to receive highly sensitive and specific screening information for common trisomy from as early as 10 weeks gestation, altering the traditional pathway FTCS pathway. The retention of the 11-13-week NT ultrasound remains important in the detection of structural anomalies; however, the optimal management of pregnancies with a low-risk NIPT result and an isolated increased NT measurement in an era of advanced genomic testing options is a new dilemma for clinicians. For parents, the prolonged period between the initial diagnosis in first trimester, and prognostic information at each successive stage of investigations up to 22-24 weeks, can be emotionally challenging. This article addresses the common questions from parents and clinicians as they navigate the uncertainty of having a fetus diagnosed with an increased NT after a low-risk NIPT result and presents suggested approaches to management.

From screening chromosomal anomalies to early diagnosis of fetal malformations

PURPOSE OF REVIEW

The aim of this review is to understand why and how to improve the detection rate of the fetal anomalies in the first trimester.

RECENT FINDINGS

The role of the first trimester is evolving from aneuploid and basic anatomical screening to a necessary tool to identifying early fetal malformations. In the past 20 years, several studies were conducted to assess the detection rate of anomalies in the first trimester, and despite the improvement in the diagnoses of spina bifida and cleft lip, many anomalies detectable in the first trimester are still being diagnosed in the second trimester scan. Analyzing the factors that improve the detection rate can show the reason why, even in recent years, only 50% of the anomalies are diagnosed in the first trimester.

SUMMARY

Thanks to the improvement in the ultrasound technology, the fetus can be thoroughly studied even in early gestation and it is, therefore, indispensable to increase the detection rate of the anomalies diagnosable from the first trimester. The sonographer's utmost attention should be applied to all pregnancies, not only in high-risk patients, and new protocols based on the mid trimester scan are needed to spread the concept of first trimester anatomical scan.

Chances and Challenges of New Genetic Screening Technologies (NIPT) in Prenatal Medicine from a Clinical Perspective: A Narrative Review

In 1959, 63 years after the death of John Langdon Down, Jérôme Lejeune discovered trisomy 21 as the genetic reason for Down syndrome. Screening for Down syndrome has been applied since the 1960s by using maternal age as the risk parameter. Since then, several advances have been made. First trimester screening, combining maternal age, maternal serum parameters and ultrasound findings, emerged in the 1990s with a detection rate (DR) of around 90-95% and a false positive rate (FPR) of around 5%, also looking for trisomy 13 and 18. With the development of high-resolution ultrasound, around 50% of fetal anomalies are now detected in the first trimester. Non-invasive prenatal testing (NIPT) for trisomy 21, 13 and 18 is a highly efficient screening method and has been applied as a first-line or a contingent screening approach all over the world since 2012, in some countries without a systematic screening program. Concomitant with the rise in technology, the possibility of screening for other genetic conditions by analysis of cfDNA, such as sex chromosome anomalies (SCAs), rare autosomal anomalies (RATs) and microdeletions and duplications, is offered by different providers to an often not preselected population of pregnant women. Most of the research in the field is done by commercial providers, and some of the tests are on the market without validated data on test performance. This raises difficulties in the counseling process and makes it nearly impossible to obtain informed consent. In parallel with the advent of new screening technologies, an expansion of diagnostic methods has begun to be applied after invasive procedures. The karyotype has been the gold standard for decades. Chromosomal microarrays (CMAs) able to detect deletions and duplications on a submicroscopic level have replaced the conventional karyotyping in many countries. Sequencing methods such as whole exome sequencing (WES) and whole genome sequencing (WGS) tremendously amplify the diagnostic yield in fetuses with ultrasound anomalies.

First-trimester fetal neurosonography: technique and diagnostic potential

Most brain abnormalities are present in the first trimester, but only a few are detected so early in gestation. According to current recommendations for first-trimester ultrasound, the fetal head structures that should be visualized are limited to the cranial bones, the midline falx and the choroid-plexus-filled ventricles. Using this basic approach, almost all cases of acrania, alobar holoprosencephaly and cephalocele are detected. However, the majority of other fetal brain abnormalities remain undiagnosed until the midtrimester. Such anomalies would be potentially detectable if the sonographic study were to be extended to include additional anatomic details not currently included in existing guidelines. The aim of this review article is to describe how best to assess the normal fetal brain by first-trimester expert multiplanar neurosonography and to demonstrate the early sonographic findings that characterize some major fetal brain abnormalities. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Psychological outcomes, knowledge and preferences of pregnant women on first-trimester screening for fetal structural abnormalities: A prospective cohort study

INTRODUCTION

The primary aim of this study is to investigate the impact of a 13-week anomaly scan on the experienced levels of maternal anxiety and well-being. Secondly, to explore women's knowledge on the possibilities and limitations of the scan and the preferred timing of screening for structural abnormalities.

MATERIAL AND METHODS

In a prospective-cohort study conducted between 2013-2015, pregnant women in the North-Netherlands underwent a 13-week anomaly scan. Four online-questionnaires (Q1, Q2, Q3 and Q4) were completed before and after the 13- and the 20-week anomaly scans. In total, 1512 women consented to participate in the study and 1118 (74%) completed the questionnaires at Q1, 941 (64%) at Q2, 807 (55%) at Q3 and 535 (37%) at Q4. Psychological outcomes were measured by the state-trait inventory-scale (STAI), the patient's positive-negative affect (PANAS) and ad-hoc designed questionnaires.

RESULTS

Nine-nine percent of women wished to be informed as early as possible in pregnancy about the absence/presence of structural abnormalities. In 87% of women levels of knowledge on the goals and limitations of the 13-week anomaly scan were moderate-to-high. In women with a normal 13-week scan result, anxiety levels decreased (P < .001) and well-being increased over time (P < .001). In women with false-positive results (n = 26), anxiety levels initially increased (STAI-Q1: 39.8 vs. STAI-Q2: 48.6, P = 0.025), but later decreased around the 20-week anomaly scan (STAI-Q3: 36.4 vs. STAI-Q4: 34.2, P = 0.36).

CONCLUSIONS

The 13-week scan did not negatively impact the psychological well-being of pregnant women. The small number of women with screen-positive results temporarily experienced higher anxiety after the scan but, in false-positive cases, anxiety levels normalized again when the abnormality was not confirmed at follow-up scans. Finally, most pregnant women have moderate-to-high levels of knowledge and strongly prefer early screening for fetal structural abnormalities.

How often do we identify fetal abnormalities during routine third-trimester ultrasound? A systematic review and meta-analysis

BACKGROUND

Routine third-trimester ultrasound is frequently offered to pregnant women to identify fetuses with abnormal growth. Infrequently, a congenital anomaly is incidentally detected.

OBJECTIVE

To establish the prevalence and type of fetal anomalies detected during routine third-trimester scans using a systematic review and meta-analysis.

SEARCH STRATEGY

Electronic databases (MEDLINE, Embase and the Cochrane library) from inception until August 2019.

SELECTION CRITERIA

Population-based studies (randomised control trials, prospective and retrospective cohorts) reporting abnormalities detected at the routine third-trimester ultrasound performed in unselected populations with prior screening. Case reports, case series, case-control studies and reviews without original data were excluded.

DATA COLLECTION AND ANALYSIS

Prevalence and type of anomalies detected in the third trimester. We calculated pooled prevalence as the number of anomalies per 1000 scans with 95% confidence intervals. Publication bias was assessed.

MAIN RESULTS

The literature search identified 9594 citations: 13 studies were eligible representing 141 717 women; 643 were diagnosed with an unexpected abnormality. The pooled prevalence of a new abnormality diagnosed was 3.68 per 1000 women scanned (95% CI 2.72-4.78). The largest groups of abnormalities were urogenital (55%), central nervous system abnormalities (18%) and cardiac abnormalities (14%).

CONCLUSION

Combining data from 13 studies and over 140 000 women, we show that during routine third-trimester ultrasound, an incidental fetal anomaly will be found in about 1 in 300 scanned women. This information should be taken into account when taking consent from women for third-trimester ultrasound and when designing and assessing cost of third-trimester ultrasound screening programmes.

TWEETABLE ABSTRACT

One in 300 women attending a third-trimester scan will have a finding of a fetal abnormality.

Socioeconomic and geographic variations in antenatal care coverage in Angola: further analysis of the 2015 demographic and health survey

BACKGROUND

In African countries, including Angola, antenatal care (ANC) coverage is suboptimal and maternal mortality is still high due to pregnancy and childbirth-related complications. There is evidence of disparities in the uptake of ANC services, however, little is known about both the socio-economic and geographic-based disparity in the use of ANC services in Angola. The aim of this study was to assess the extent of socio-economic, urban-rural and subnational inequality in ANC coverage in Angola.

METHODS

We analyzed data from the 2015 Angola Demographic and Health Survey (ADHS) using the World Health Organization (WHO) Health Equity Assessment Toolkit (HEAT) software. The analysis consisted of disaggregated ANC coverage rates using four equity stratifiers (economic status, education, residence, and region) and four summary measures (Difference, Population Attributable Risk, Ratio and Population Attributable Fraction). To measure statistical significance, an uncertainty interval (UI) of 95% was constructed around point estimates.

RESULTS

The study showed both absolute and relative inequalities in coverage of ANC services in Angola. More specifically, inequality favored women who were rich (D = 54.2, 95% UI; 49.59, 58.70, PAF = 43.5, 95% UI; 40.12, 46.92), educated (PAR = 19.9, 95% UI; 18.14, 21.64, R = 2.14, 95% UI; 1.96, 2.32), living in regions such as Luanda (D = 51.7, 95% UI; 43.56, 59.85, R = 2.64, 95% UI; 2.01, 3.26) and residing in urban dwellings (PAF = 20, 95% UI; 17.70, 22.38, PAR = 12.3, 95% UI; 10.88, 13.75).

CONCLUSION

The uptake of ANC services were lower among poor, uneducated, and rural residents as well as women from the Cuanza Sul region. Government policy makers must consider vulnerable subpopulations when designing needed interventions to improve ANC coverage in Angola to achieve the 2030 Sustainable Development Goal of reducing global maternal mortality ratio to 70 deaths per 100,000 live births.

Investigation of copeptin levels in foetal congenital central nervous system anomalies

Copeptin has been shown to be associated with central nervous system pathologies. The aim of this study was to investigate the relationship between serum CCP levels and central nervous system (CNS) anomalies. In this case-control study, those at 9-14 weeks of gestation serum levels of copeptin, were assessed in pregnant women whose foetuses subsequently developed CNS anomalies (group 1: n = 60) and compared with gestational age-matched pregnant women who exhibited normal pregnancy outcomes (group 2: n = 48). The mean copeptin levels were 1.58 ± 0.40 ng/mL and 1.11 ± 0.36 ng/mL in the CNS anomalies and control groups, respectively (p < .0001). An increased level of copeptin independently predicts development of CNS anomalies, suggesting that copeptin can be used for prediction and discrimination of CNS anomalies in normal pregnancies at 9-14 weeks of gestation.Impact statementWhat is already known on this subject? There is no test or method to diagnose CNS anomalies in the first trimester of pregnancy. This study presents the first and new information on the relationship between serum copeptin levels and central nervous system anomalies in pregnant women whose foetuses subsequently developed CNS anomalies.What do the results of this study add? I have strongly demonstrated differences in maternal CPP levels between CNS anomalous pregnancies and healthy controls.What are the implications of these findings for clinical practice and/or further research? It has been thought that copeptin appears to be an ideal marker for central nervous system anomaly prediction at 9-14 weeks of gestational age and if confirmed in larger prospective studies. Finally, these results could not be used as parameters for prenatal CNS screening. Advanced studies, well-structured and conducted on larger populations are needed to investigate the issue further.

Should cell-free DNA testing be used in pregnancy with increased fetal nuchal translucency?

OBJECTIVE

To assess the frequency of atypical chromosomal and submicroscopic anomalies, as well as fetal structural abnormalities, observed on first-trimester ultrasound scan in fetuses with nuchal translucency (NT) thickness > 99^th centile, in order to evaluate the suitability of using standard cell-free DNA (cfDNA) testing as the sole screening test in these pregnancies.

METHODS

This was a retrospective cohort study of 226 fetuses with NT > 99^th centile at 11-14 weeks' gestation, between January 2013 and December 2017, in a clinical setting in which greater than 95% of pregnant women receive first-trimester combined screening. All patients underwent genetic testing by means of quantitative fluorescence polymerase chain reaction and chromosomal microarray analysis, mainly in chorionic villus samples. We assessed the theoretical yield of two cfDNA testing models, targeted cfDNA (chromosomes 21, 18 and 13) and extended cfDNA (chromosomes 21, 18, 13 and sex chromosomes), and compared it with that of cytogenetic testing and ultrasound assessment in the first and second or third trimesters.

RESULTS

In the 226 fetuses analyzed, cytogenetic testing revealed 84 (37%) anomalies, including 68 typical aneuploidies (involving chromosomes 13, 18 or 21), six sex chromosome aneuploidies (four cases of monosomy X and two of trisomy X), three clinically relevant atypical chromosomal anomalies (one trisomy 22, one trisomy 21 mosaicism and one unbalanced translocation), five submicroscopic pathogenic variants and two cases with Noonan syndrome. Targeted and extended cfDNA testing would miss at least 12% (10/84) and 19% (16/84), respectively, of genetic anomalies, accounting for 4.4% and 7.1% of the fetuses with an increased NT, respectively. Finally, of the 142 fetuses with no identified genetic anomaly, a major fetal malformation was observed in 15 (10.6%) fetuses at the early anomaly scan, and in 19 (13.4%) in the second or third trimester.

CONCLUSIONS

cfDNA does not appear to be the appropriate genetic test in fetuses with NT > 99^th centile, given that it would miss 12-19% of genetic anomalies in this group. Additionally, first-trimester ultrasound will identify a major structural abnormality in 11% of the fetuses with NT > 99^th centile and no genetic anomaly. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Is there still a role for nuchal translucency measurement in the changing paradigm of first trimester screening?

Objectives

To give an overview of the genetic and structural abnormalities occurring in fetuses with nuchal translucency (NT) measurement exceeding the 95th percentile at first‐trimester screening and to investigate which of these abnormalities would be missed if cell‐free fetal DNA (cfDNA) were used as a first‐tier screening test for chromosomal abnormalities.

Methods

This is a national study including 1901 pregnancies with NT≥95th percentile referred to seven university hospitals in the Netherlands between 1 January 2010 and 1 January 2016. All cases with unknown pregnancy outcome were excluded. Results of detailed ultrasound examinations, karyotyping, genotyping, pregnancy and neonatal outcomes, investigation by a clinical geneticist and post‐mortem investigations were collected.

Results

In total, 821 (43%) pregnancies had at least one abnormality. The rate of abnormalities was 21% for fetuses with NT between 95^th and 99^th percentile and 62% for fetuses with NT≥99^th percentile. Prevalence of single‐gene disorders, submicroscopic, chromosomal and structural abnormalities was 2%, 2%, 30% and 9%, respectively.

Conclusion

Although cfDNA is superior to the combined test, especially for the detection of trisomy 21, 34% of the congenital abnormalities occurring in fetuses with increased NT may remain undetected in the first trimester of pregnancy, unless cfDNA is used in combination with fetal sonographic assessment, including NT measurement.

What's already known about this topic?

Nuchal translucency is associated with a wide range of chromosomal and structural abnormalities.

What does this study add?

If cell‐free DNA were used as the only first trimester screening test, 34% of fetal congenital abnormalities would be missed in the first trimester of pregnancy.

In high‐risk pregnancies with increased nuchal translucency (NT≥95^th percentile), 23% of abnormalities are found in fetuses with NT between 95^th and 99^th percentile.

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.

Diagnosis of fetal non-chromosomal abnormalities on routine ultrasound examination at 11-13 weeks' gestation

OBJECTIVE

To examine the performance of the routine 11-13-week scan in detecting fetal non-chromosomal abnormalities.

METHODS

This was a retrospective study of prospectively collected data from 100 997 singleton pregnancies attending for a routine ultrasound examination of fetal anatomy, performed according to a standardized protocol, at 11-13 weeks' gestation. All continuing pregnancies had an additional scan at 18-24 weeks and 71 754 had a scan at either 30-34 or 35-37 weeks. The final diagnosis of fetal abnormality was based on the results of postnatal examination in cases of live birth and on the findings of the last ultrasound examination in cases of pregnancy termination, miscarriage or stillbirth. The performance of the 11-13-week scan in the detection of fetal abnormalities was determined.

RESULTS

The study population contained 1720 (1.7%) pregnancies with a fetal abnormality, including 474 (27.6%) detected on the first-trimester scan, 926 (53.8%) detected on the second-trimester scan and 320 (18.6%) detected in the third trimester or postnatally. At 11-13 weeks' gestation, we diagnosed all cases of acrania, alobar holoprosencephaly, encephalocele, tricuspid or pulmonary atresia, pentalogy of Cantrell, ectopia cordis, exomphalos, gastroschisis and body-stalk anomaly and > 50% of cases of open spina bifida, hypoplastic left heart syndrome, atrioventricular septal defect, complex heart defect, left atrial isomerism (interrupted inferior vena cava with normal intracardiac anatomy), lower urinary tract obstruction, absence of extremities, fetal akinesia deformation sequence and lethal skeletal dysplasia. Common abnormalities that were detected in < 10% of cases at 11-13 weeks included ventriculomegaly, agenesis of the corpus callosum, isolated cleft lip, congenital pulmonary airway malformation, ventricular septal defect, abdominal cysts, unilateral renal agenesis or multicystic kidney, hydronephrosis, duplex kidney, hypospadias and talipes.

CONCLUSIONS

A routine 11-13-week scan, carried out according to a standardized protocol, can identify many severe non-chromosomal fetal abnormalities. A summary statistic of the performance of the first-trimester scan is futile because some abnormalities are always detectable, whereas others are either non-detectable or sometimes detectable. To maximize prenatal detection of abnormalities, additional scans in both the second and third trimesters are necessary. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Clinical application of chromosomal microarray analysis in fetuses with increased nuchal translucency and normal karyotype

Background

Submicroscopic chromosomal imbalance is associated with an increased nuchal translucency (NT). Most previous research has recommended the use of chromosomal microarray analysis (CMA) for prenatal diagnosis if the NT ≥ 3.5 mm. However, there is no current global consensus on the cutoff value for CMA. In this study, we aimed to discuss the fetuses with smaller increased NT which was between cutoff value of NT for karyotype analysis (NT of 2.5 mm in China) and the recommended cutoff value for CMA (NT of 3.5 mm) whether should be excluded from CMA test.

Methods

Singleton pregnant women (N = 192) who had undergone invasive procedures owing to an increased NT (NT ≥ 2.5 mm) were enrolled. Fetal cells were collected and subjected to single nucleotide polymorphism array and karyotype analyses simultaneously. Cases were excluded if the karyotype analysis indicated aneuploidy and apparent structural aberrations.

Results

Fourteen cases of aneuploidy and four cases of structural abnormalities were excluded. Of the remaining 174 cases, 119 fetuses had NTs of 2.5–3.4 mm, and 55 fetuses with NT ≥ 3.5 mm. Eleven copy number variants (CNVs) were identified. In fetuses with smaller NTs, six (6/119, 5.9%) variations were detected, including two (2/119, 1.6%) clinically significant CNVs (pathogenic or likely pathogenic CNV), one  likely benign CNV, two variants unknown significance, and one incidental CNV. Five (5/55, 9.1%) variations were found in fetuses with NT ≥ 3.5 mm. Among these CNVs, three (3/55, 5.5%) cases had clinically significant CNVs, and two had likely benign CNV. There were no statistically significant differences in the incidence of all CNVs and clinically significant CNVs in the two groups (p > 0.05).

Conclusion

CMA improved the diagnostic yield of chromosomal aberrations for fetuses with NTs of 2.5–3.4 mm and apparently normal karyotype, regardless of whether other ultrasonic abnormalities were observed.

Anterior abdominal wall defects managed at a tertiary maternal-fetal medicine service in New Zealand: What counselling advice can we offer parents?

BACKGROUND

Anterior abdominal wall defects, including gastroschisis and omphalocoele, are common fetal anomalies. The management remains complicated, and their diagnosis may lead to significant parental distress. Effective parental counselling may impact on parental perceptions of the defect and help guide pregnancy management.

AIMS

Using contemporary data, we aimed to describe clinical outcomes of patients with gastroschisis or omphalocoele in order to provide information for clinicians to assist in parental counselling.

MATERIALS AND METHODS

We followed a case-series of patients with anterior abdominal wall defects referred to our regional Maternal Fetal Medicine services from 2011 to 2016. Outcomes of interest antenatally included details of diagnosis, associated anomalies and outcomes of pregnancy and postnatally included the nature of surgical repair, hospital stay and secondary complications until initial discharge.

RESULTS

Eighty babies with gastroschisis were referred antenatally, and 72 were liveborn. Forty-nine babies with omphalocoele were referred antenatally, and 24 were liveborn. One further neonate with omphalocoele was postnatally diagnosed. Seventy-one neonates with gastroschisis progressed to operation, 30 developed complications post-surgery, and 68 survived until initial discharge. Twenty-two neonates with omphalocoele progressed to surgery, only two developed complications, and 21 survived until initial discharge. Eight of the surviving neonates with omphalocoele had associated structural abnormalities. The median hospital stay was 27 and eight days for gastroschisis and omphalocoele, respectively.

CONCLUSION

Neonates with gastroschisis can have complex postnatal periods. Omphalocoele is associated with high antenatal mortality, especially in the presence of associated abnormalities; however, surviving neonates may have uneventful postnatal periods.

Early fetal ultrasound screening for major congenital heart defects without Doppler

OBJECTIVE

Congenital heart defects are the most common major structural fetal abnormalities. Color flow mapping has played a dominant role in the detection of abnormalities during the first trimester, regardless of the International Society of Ultrasound in Obstetrics and Gynecology warning on the use of Doppler during early pregnancy. The aim of our study was to investigate the use of transvaginal two-dimensional sonography without Doppler for assessing the four-chamber view and the outflow tract view of fetuses at 11-13 weeks of gestation for cardiac screening of major congenital heart defects.

STUDY DESIGN

This was a prospective observational study conducted in the Fetal Medicine Unit of Cabueñes University Hospital, between May 2014 and August 2015. Only low risk-pregnancies were studied. All ultrasonographic examinations were performed by two experienced sonographers in maternal-fetal medicine. The combination of high-frequency transvaginal (nine MHz) and transabdominal (six MHz) ultrasonography transducers were used. An early cardiac screening was performed in 97% of cases. Statistical analysis was carried out using successive multivariate logistic regression models in order to investigate the effect of crown-rump length and body mass index on the probability of visualizing the four-chamber view and/or the outflow tract view.

RESULTS

663 low-risk pregnant women were included. Regarding the transvaginal approach, neither the crown-rump length nor the body mass index had a statistically significant relationship on the probability of visualization of the four-chamber view and outflow tract view. For the transabdominal approach, the crown-rump length and the body mass index presented a statistically significant effect on the visualization of the four-chamber view and the outflow tract view. Using the transvaginal approach: the success rate of performing a four-chamber view was 89.4% and 82.4% for the outflow tract view. Using the transabdominal approach: the success rate of performing a four-chamber view was 77.8% and 61.5% for the outflow tract view. Four major congenital heart defects were diagnosed, and the prenatal ultrasonagraphic diagnosis was confirmed for all cases.

CONCLUSIONS

Routine first-trimester ultrasonagraphy without Doppler, when performed by experienced sonographers, can effectively identify major congenital heart defects. Additional multicenter well designed studies should clarify the feasibility of this approach.

First trimester physiological development of the fetal foot position using three-dimensional ultrasound in virtual reality

Aim

In anatomic studies of the embryo, it has been established that during the development of the lower limb, several changes in foot position can be observed defined as a temporary ‘physiological clubfoot’. The aim of this study was to develop and test a measurement tool for objective documentation of the first trimester foot position in vivo and made an attempt to create a chart for first trimester foot position.

Methods

We developed a virtual orthopedic protractor for measuring foot positioning using three‐dimensional virtual reality visualization. Three‐dimensional ultrasound volumes of 112 pregnancies of women examined during the first trimester were studied in a BARCO I‐Space. The frontal angle (plantar flexion) and the lateral angle (adduction) between the leg and foot were measured from 8 until 13 weeks gestational age.

Results

We observed that the frontal angle steadily decreases, whereas the lateral angle first increases, resulting in transient physiological clubfeet position at 10‐ to 11‐week gestation, followed by a decrease to a normal foot position.

Conclusion

A transient clubfoot position is present during the normal development of the lower limbs, and it has been measured in vivo for the first time. This study emphasizes that a diagnosis of congenital clubfoot should not be made in the first trimester of pregnancy.

Diagnosis of Fetal Structural Anomalies at 11 to 14 Weeks

OBJECTIVES

To assess the performance of first-trimester ultrasound (US) in identifying major fetal structural abnormalities in an unselected population.

METHODS

We conducted a retrospective analysis of all pregnancies that underwent the 11- to 14-week scan in the Fetal Medicine Department of Filantropia Hospital in Bucharest, which were prospectively examined within our screening program. The purpose of the first-trimester US was to evaluate the risk for chromosomal abnormalities and to conduct fetal anatomic examination using a detailed protocol.

RESULTS

Our population consisted of 7480 pregnant patients (7576 fetuses). The follow-up was completed for 6045 patients (6114 fetuses). The prevalence of major structural anomalies was 1.89%. In the first trimester, we identified 79% of all major structural anomalies. The highest detection rates were achieved for abdominal wall defects (100%), major central nervous system anomalies (88%), cardiac defects (74%), and skeletal anomalies (71%). The nuchal translucency was increased in 35% of the cases with structural anomalies, and 95% of these were diagnosed in the first trimester. Seventy percent of the patients who presented with structural anomalies and a normal nuchal translucency were diagnosed in the first trimester.

CONCLUSIONS

Our results emphasize the importance of performing a detailed US examination at 11 to 14 weeks' gestation in identification of fetal structural defects.

Early Detection of Structural Anomalies in a Primary Care Setting in the Netherlands

OBJECTIVE

This study assessed the percentage and type of congenital anomalies diagnosed at first-trimester ultrasound (US) scan in a primary care setting without following a standardized protocol for fetal anatomical assessment.

MATERIALS AND METHODS

US scans performed between 11+0 and 13+6 weeks of gestation in pregnancies with estimated date of delivery between January 1, 2012 and January 1, 2016 were searched. Data were supplemented with results of 20-week scans and pregnancy outcome.

RESULTS

Of all scans, 38.6% were dating scans and 61.4% were part of first-trimester screening. Anomalies were diagnosed prenatally in 200 (1.8%) fetuses; 81 (0.7%) were chromosomal and 119 (1.1%) were structural. Of all prenatally detected anomalies, 27% (n = 32) were detected at first-trimester scan, with a false-positive rate of 0.04%. All cases of anencephaly (n = 4), encephalocele (n = 2), exomphalos (n = 9), megacystis (n = 4), and limb reduction (n = 1) were diagnosed. First-trimester detection of gastroschisis and congenital heart defects was 67 and 19%, respectively.

CONCLUSION

In a primary care setting, global fetal anatomical assessment at first-trimester scan without following a standardized protocol detects about 30% of all structural anomalies and most of the severe anomalies, with an extremely low false-positive rate. We hypothesize that additional training and use of a systematic protocol would improve early detection of structural anomalies.

Prenatal limb defects: Epidemiologic characteristics and an epidemiologic analysis of risk factors

To analyze prenatal ultrasound data for fetal limb deformities in high-risk pregnant women and the risk factors for prenatal limb defects in high-risk pregnant women.This was a retrospective study of high-risk pregnant women at the multidisciplinary consultation center from January 2006 to December 2015. When deformities were definitively diagnosed in the first trimester by ultrasound, patients were recommended to undergo an abortion, and fetal abnormalities were confirmed by pathological examination (both gross anatomic examinations and fetal chromosome and genetic tests). The risk factors for fetal limb deformities and other congenital malformations were analyzed by multifactor analysis.Of the 4088 fetuses recorded, 144 (3.52%) were diagnosed with limb abnormalities. The abnormalities included 70 (48.61%) clubfoot/clubhand cases, with 5 polydactyly, 5 syndactyly, 4 flexion toe, 4 split hand/foot malformation, 3 overlapping fingers, and 49 congenital talipes equinovarus. A total of 6 (4.17%) and 13 (9.02%) fetuses had phocomelia and imperfect osteogenesis, respectively; 22 (15.28%) cases showed achondrogenesis; 19 (13.19%) and 12 (8.33%) had partial limb deletion absence and joint movement malfunction, respectively.In the high-risk population with limb deformities (144 patients), 19 (13.19%) were ≥35 years old, 6 (4.17%) had family history of congenital malformations, 14 (9.72%) had abnormal reproductive history, 21 (14.6%) had harmful chemical exposure, 6 (4.2%) had early TORCH infections, 16 (11.1%) had gestational diabetes, 9 (6.3%) had hypertension, 3 (2.1%) took glucocorticoid, 9 (6.3%) took sedatives.In the high-risk population with other congenital malformations except limb deformities (3766 patients), 144 pregnant women were randomly selected. In the high-risk population with other congenital malformations (144 patients), 9 (6.25%) were ≥35 years old, 7 (4.86%) had family history of congenital malformations, 10 (6.94%) had abnormal reproductive history, 22 (15.28%) had harmful chemical exposure, 5 (3.47%) had early TORCH infections, 12 (8.33%) had gestational diabetes, 11 (7.64%) had hypertension, 4 (2.78%) took glucocorticoid, 11 (7.64%) took sedatives.Ultrasound can provide adequate evidence for fetal limb deformities evaluation in most patients. Fetal limb deformity cases showed a significantly higher rate than other congenital malformations for advanced maternal age (≥35 years old).

Effectiveness of 12-13-week scan for early diagnosis of fetal congenital anomalies in the cell-free DNA era

OBJECTIVES

The main aim of this study was to assess the proportion and type of congenital anomalies, both structural and chromosomal, that can be detected at an early scan performed at 12-13 weeks' gestation, compared with at the 20-week structural anomaly scan offered under the present screening policy. Secondary aims were to evaluate the incidence of false-positive findings and ultrasound markers at both scans, and parental choice regarding termination of pregnancy (TOP).

METHODS

Sonographers accredited for nuchal translucency (NT) measurement were asked to participate in the study after undergoing additional training to improve their skills in late first-trimester fetal anatomy examination. The early scans were performed according to a structured protocol, in six ultrasound practices and two referral centers in the north-east of The Netherlands. All women opting for the combined test (CT) or with an increased a-priori risk of fetal anomalies were offered a scan at 12-13 weeks' gestation (study group). All women with a continuing pregnancy were offered, as part of the 'usual care', a 20-week anomaly scan.

RESULTS

The study group consisted of 5237 women opting for the CT and 297 women with an increased a-priori risk of anomalies (total, 5534). In total, 51 structural and 34 chromosomal anomalies were detected prenatally in the study population, and 18 additional structural anomalies were detected after birth. Overall, 54/85 (63.5%) anomalies were detected at the early scan (23/51 (45.1%) structural and all chromosomal anomalies presenting with either an increased risk at first-trimester screening or structural anomalies (31/34)). All particularly severe anomalies were detected at the early scan (all cases of neural tube defect, omphalocele, megacystis, and multiple severe congenital and severe skeletal anomalies). NT was increased in 12/23 (52.2%) cases of structural anomaly detected at the early scan. Of the 12 cases of heart defects, four (33.3%) were detected at the early scan, five (41.7%) at the 20-week scan and three (25.0%) after birth. False-positive diagnoses at the early scan and at the 20-week scan occurred in 0.1% and 0.6% of cases, respectively, whereas ultrasound markers were detected in 1.4% and 3.0% of cases, respectively. After first- or second-trimester diagnosis of an anomaly, parents elected TOP in 83.3% and 25.8% of cases, respectively.

CONCLUSIONS

An early scan performed at 12-13 weeks' gestation by a competent sonographer can detect about half of the prenatally detectable structural anomalies and 100% of those expected to be detected at this stage. Particularly severe anomalies, often causing parents to choose TOP, are amenable to early diagnosis. The early scan is an essential part of modern pregnancy care. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

First and second trimester screening for fetal structural anomalies

Fetal structural anomalies are found in up to 3% of all pregnancies and ultrasound-based screening has been an integral part of routine prenatal care for decades. The prenatal detection of fetal anomalies allows for optimal perinatal management, providing expectant parents with opportunities for additional imaging, genetic testing, and the provision of information regarding prognosis and management options. Approximately one-half of all major structural anomalies can now be detected in the first trimester, including acrania/anencephaly, abdominal wall defects, holoprosencephaly and cystic hygromata. Due to the ongoing development of some organ systems however, some anomalies will not be evident until later in the pregnancy. To this extent, the second trimester anatomy is recommended by professional societies as the standard investigation for the detection of fetal structural anomalies. The reported detection rates of structural anomalies vary according to the organ system being examined, and are also dependent upon factors such as the equipment settings and sonographer experience. Technological advances over the past two decades continue to support the role of ultrasound as the primary imaging modality in pregnancy, and the safety of ultrasound for the developing fetus is well established. With increasing capabilities and experience, detailed examination of the central nervous system and cardiovascular system is possible, with dedicated examinations such as the fetal neurosonogram and the fetal echocardiogram now widely performed in tertiary centers. Magnetic resonance imaging (MRI) is well recognized for its role in the assessment of fetal brain anomalies; other potential indications for fetal MRI include lung volume measurement (in cases of congenital diaphragmatic hernia), and pre-surgical planning prior to fetal spina bifida repair. When a major structural abnormality is detected prenatally, genetic testing with chromosomal microarray is recommended over routine karyotype due to its higher genomic resolution.

The impact of maternal obesity on completion of fetal anomaly screening

OBJECTIVE

To examine the impact of maternal obesity on completion of fetal anomaly screening.

METHODS

A retrospective analysis of 500 anomaly scans (19+0-21+6 weeks) was included. Women were categorised according to the World Health Organisation (WHO) body mass index (BMI) classification: normal weight (18.50-24.99 kg/m2), overweight (25.00-29.99 kg/m2), obese class I (30-34.99 kg/m2), obese class II (35.00-39.99 kg/m2) and obese class III (≥40.00 kg/m2). A fetal anomaly imaging scoring system was developed from the National Health Service (NHS) Fetal Anomaly Screening Programme standard to evaluate scans.

RESULTS

Image quality deteriorated as BMI increased and was significantly different across the BMI categories (P<0.001). Performance was poorest in imaging of the fetal chest and was significantly different across BMI categories (P<0.001). In obese class III, 33% of four-chamber cardiac views and 38% of outflow tract views were not obtained. In total, 119 women (23.6%) had an incomplete scan. In obese class III, 44.1% of scans were incomplete compared with 10.2% in the normal BMI category (P<0.001). Of 117 women attending for repeat scans, 78.6% were complete, 11.1% were incomplete, 6.8% were advised to re-attend and 3.4% were referred to Fetal Medicine.

CONCLUSION

Maternal obesity has a significant impact on completion of fetal anomaly screening.

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.

Fetal Anatomic Imaging Between 11 and 14 Weeks Gestation

Fetal imaging between 11 and 14 weeks is a standard component of prenatal risk assessment for aneuploidy. Evaluating the fetus during this gestational age window provides the opportunity to reliably examine anatomic structures. Using a defined imaging protocol, approximately 50% of major abnormalities can be detected. Some abnormalities should almost always be detected, some may be detected on occasion and others are not currently detectable. Imagers must be familiar with embryologic patterns of development and natural history of anomalies. Patients must be informed of the limitations of early anatomic evaluation. Currently, early anatomic evaluation does not replace the standard second trimester evaluation.

Omphalocele and Gastroschisis in Newborns: Over 16 Years of Experience from a Single Clinic

Infants born with potentially life-threatening conditions of omphalocele and gastroschisis may require long-term hospitalization. We aimed to compare the outcomes of these two conditions occurring over a 16-year period (2001-16). It is a retrospective study of 19 newborns undergoing surgery for these two abdominal wall defects (8 patients with omphalocele and 11 cases of gastroschisis). The average birth weights for the newborns with omphaloceles and gastroschisis were 2554.5 g and 2248.6 g respectively. Associated anomalies included trisomy 18, Beckwith-Wiedemann syndrome, congenital heart disease, Meckel’s diverticulum, inguinal hernias, renal deformities, limb deformities, cryptorchidism, body stalk anomalies, and closed gastroschisis. The average hospital stay for the newborns with omphaloceles and gastroschisis were 42.6 days 50.2 days respectively. The time to the start of postoperative nutritional supplementation for the newborns with omphaloceles and gastroschisis were 4.3 days for the infants with omphaloceles and 7.3 days for respectively. The survival rates for the newborns with omphaloceles and gastroschisis were similar, 87.5% and 81.8% respectively. Survival rates in omphalocele correlated negatively with associated anomalies. In gastroschisis cases, strict care is necessary when intestinal dilation is observed via fetal sonography.

Outcomes of infants with abdominal wall defects over 18years

BACKGROUND/PURPOSE

Infants with abdominal wall defects (AWD) are at risk of poor outcomes including prolonged hospitalization, infections and mortality. Our objective was to describe and compare the outcomes of infants admitted with gastroschisis and omphalocele over 18years.

METHODS

Population-based study of clinical data and outcomes of live-born infants with AWD admitted to all tertiary-level neonatal intensive care units in New South Wales and Australian Capital Territory from 1992 to 2009.

RESULT

There were 502 infants with AWD - 336 gastroschisis, 166 omphalocele. Infants with gastroschisis required a longer duration of total parenteral nutrition (19 vs 4days, p<0.05), longer hospitalization (28 vs 15days, p<0.05) and had a higher rate of systemic infection [23.5% vs 13.3%, OR 1.77 (1.15-2.74), p<0.05] compared to infants with omphalocele. Overall, omphalocele infants had higher mortality rate compared to gastroschisis infants [OR 2.77 (1.53, 5.04), p<0.05]. Gastroschisis mortality rates increased from epoch 1 to epoch 3 (4.2% to 8.8%).

CONCLUSION

Compared to infants with omphalocele, infants with gastroschisis required significantly longer hospitalization and parenteral nutrition with higher rates of infection. Infants with omphalocele had higher overall mortality rates. However, there has been an increase in the gastroschisis mortality rates but the cause for this is unclear.

Appearance of fetal posterior fossa at 11-14 weeks in fetuses with Dandy-Walker malformation or chromosomal anomalies

OBJECTIVE

To describe the sonographic appearance of fetal posterior fossa anatomy at 11-14 weeks of pregnancy and to assess the outcome of fetuses with increased intracranial translucency (IT) and/or brainstem-to-occipital bone (BSOB) diameter.

METHODS

Reference ranges for brainstem (BS), IT and cisterna magna (CM) measurements, BSOB diameter and the BS : BSOB ratio were obtained from the first-trimester ultrasound examination of 233 fetuses with normal postnatal outcome (control group). The intraobserver and interobserver variability of measurements were investigated using 73 stored ultrasound images. In addition, a study group of 17 fetuses with increased IT and/or BSOB diameter was selected to assess outcome.

RESULTS

No significant intraobserver or interobserver variability was found for any measurement in the control group. In the study group, IT was increased in all cases and BSOB diameter was above the 95(th) centile of the calculated normal range in all but two (88%) cases. In 13/17 study cases, only two of the three posterior brain spaces were recognized on ultrasound. These 13 fetuses had a larger BSOB diameter than did the four cases that showed all three posterior brain spaces, and had severe associated anomalies including Dandy-Walker malformation (DWM) and/or chromosomal anomalies.

CONCLUSIONS

Visualization of the fetal posterior fossa anatomy at 11-14 weeks' gestation is feasible. Increased fluid in the posterior brain at 11-14 weeks, particularly in the case of non-visibility of the septation that divides the future fourth ventricle from the CM, is an important risk factor for cystic posterior fossa malformations, in particular DWM, and/or chromosomal aberrations. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Usefulness of antenatal ultrasound fetal morphological assessments in the first and second trimester: a study at a single Japanese university hospital

OBJECTIVE

To assess the usefulness of antenatal ultrasound examinations for detecting fetal morphological abnormalities in the first and second trimesters.

METHODS

A prospective cohort study was conducted at a single Japanese university hospital in the period from February 2011 to September 2013. Patients in whom ultrasound was attempted at both 11 to 13 + 6 and 18 to 20 + 6 weeks' gestation and who were delivered at our hospital were enrolled. After delivery, neonatal congenital abnormalities were reviewed and compared with the ultrasound findings in the first and second trimesters.

RESULTS

The subjects were 2028 singleton babies. Abnormal fetal morphological findings were found in the first trimester in 28 cases. In these patients, fetal anomalies detected as diagnostic findings were anencephaly (2 cases) and endocardial cushion defect (2 cases). Findings suggestive of fetal anomalies were observed in 24 cases in the first trimester. Twelve cases with ultrasound findings in the first trimester, including fetal edema, anencephaly, endocardial cushion defect, exhibited an abnormal chromosome after amniocentesis. Ultrasound findings in the first trimester disappeared until 18 weeks of gestation in eight cases, and they were preserved in three cases. Fetal anomalies were primarily noted in the second trimester in 10 cases. However, after delivery, morphological abnormalities were primarily observed in 18 cases.

CONCLUSION

Major congenital abnormalities were identified in the first trimester morphological assessment. We think the use of a combination of the first trimester ultrasound screening and the second trimester ultrasound scan for detecting fetal anomalies was effective.

First-trimester Ultrasound and Aneuploidy Screening in Multifetal Pregnancies

First-trimester ultrasound provides valuable information to help optimize the management of multifetal pregnancies. First trimester ultrasound the use of ultrasound and screening for aneuploidy has been well studied in singleton pregnancies. While evidence supporting the use of ultrasound in multiple gestations is well established, aneuploidy screening continues to evolve and its role in the prenatal setting has been less well studied. We review the importance of early first trimester ultrasound in assessing gestational age and chorionicity and early identification of anomalies, and review the various methods and limitations of aneuploidy screening and invasive diagnostic procedures in multiples.

The BS/BSOB Ratio in Aneuploidy Fetuses at 11-13 Weeks Gestation

Objective: The posterior fossa of normal fetuses was evaluated and compared with those having chromosomal abnormalities at 11-13+6 weeks' gestation in Chinese population. Methods: In 518 normal fetuses referred to first trimester screening, fetal brain stem (BS) and brain stem to occipital bone distance (BSOB) were measured prospectively. The BS and BSOB were also measured on stored images in fetuses with confirmed trisomy 21 (n = 38), Trisomy 18 (n = 26), Trisomy 13 (n = 8), and monosomy X (n = 8). Results: The BS diameter and BSOB distance correlated linearly with fetal crown-rump length (CRL) by regression analysis. The BS to BSOB ratio was below the 5th percentile in 2 (5.26%), 11 (44%), 4 (50%) and 4 (50%) fetuses with trisomy 21, trisomy 18, trisomy 13 and monosomy X, respectively. Thus, both BS and BS/BSOB ratio were significantly lower in trisomy 18, trisomy 13 and monosomy X fetuses when compared to the reference range but not in fetuses with Trisomy 21. Conclusion: In ultrasound scans performed at the 11-13+6 gestation weeks, fetuses with trisomy 18, 13, and monosomy X had lower BS/BSOB ratios. But trisomy 21 fetuses did not show significant differences in posterior fossa compared to the normal population.

Detailed transabdominal fetal anatomic scanning in the late first trimester versus the early second trimester of pregnancy

OBJECTIVES

To compare visualization rates for early targeted organ scanning at gestational ages ranging from 11 weeks 3 days to 13 weeks 2 days versus 14 weeks 3 days to 16 weeks 2 days.

METHODS

We conducted a prospective longitudinal study of patients who presented for nuchal translucency (NT) screening and targeted organ scanning. Extended targeted organ scanning, including the central nervous system, face and neck, chest, heart (including complete echocardiography), digestive system, abdominal wall, urinary system, skeleton, and umbilical cord with its insertion and placenta, was performed on gravidas in 2 age ranges. Uterine artery Doppler mapping was performed during the second scan. All cases were examined twice: once at NT screening (up to 13 weeks 2 days) and again in the early second trimester.

RESULTS

A total of 408 women were recruited and scanned twice. Three abnormalities were diagnosed in the second scan that were not seen in the first: dysplastic long bones, tricuspid stenosis, and cleft lip (without palate involvement). None had chromosomal anomalies. Successful visualization rates in all organ systems exceeded 94% in the second trimester. At the first-trimester scan, some systems had high success rates, whereas others were very low; eg, in the brain, the cerebellum and posterior fossa were visualized successfully approximately 50% of the time and the upper lip only approximately 10%. On fetal echocardiography, the 4-chamber view and outflow tracts were imaged successfully approximately 40% of the time, and the kidneys approximately 35%. Uterine artery Doppler mapping was possible in all patients on at least one side. On third-trimester follow-up, we diagnosed 1 mild pulmonary stenosis, 1 autosomal recessive polycystic kidney disease, and 1 ventricular septal defect.

CONCLUSIONS

The early second-trimester scan was much more productive than targeted organ scanning performed during the NT window. When counseling women regarding the optimal time for early transabdominal targeted organ scanning, successful visualization rates for various organ systems should be considered.

Pattern of secretion of pregnancy-associated plasma protein-A (PAPP-A) during pregnancies complicated by fetal aneuploidy, in vivo and in vitro

BACKGROUND

Pregnancy-associated placental protein-A (PAPP-A) is a metalloprotease which circulates as an hetero-tetramer in maternal blood. Its maternal serum concentration in fetal trisomy 21 is decreased during the first trimester, so that PAPP-A is a useful screening biomarker. However, the regulation of PAPP-A placental secretion is unclear. We therefore investigated the secretion of PAPP-A in pregnancies complicated by fetal aneuploidies, both in vivo and in vitro.

METHODS

Maternal serum collected between 10 WG and 33 WG during 7014 normal pregnancies and 96 pregnancies complicated by fetal trisomy 21, 18, and 13 were assayed for PAPP-A using the Immulite 2000xpi system®. The pregnancies were monitored using ultrasound scanning, fetal karyotyping and placental analysis. Villous cytotrophoblasts were isolated from normal and trisomic placenta and cultured to investigate PAPP-A secretion in vitro (n=6).

RESULTS

An increased nuchal translucency during the first trimester is a common feature of many chromosomal defect but each aneuploidy has its own syndromic pattern of abnormalities detectable at the prenatal ultrasound scanning and confirmed at the fetal examination thereafter. PAPP-A levels rise throughout normal pregnancy whereas in trisomy 21, PAPP-A levels were significantly decreased, but only during the first trimester. PAPP-A levels were decreased in trisomy 13 and sharply in trisomy 18, whatever the gestational age. In vitro, PAPP-A secretion was decreased in aneuploidy, and associated with decreased hCG secretion in Trisomy 21 and 18. These biochemical profiles did not appear to be linked to any specific histological lesions affecting the placenta.

CONCLUSIONS

These profiles may reflect different quantitative and qualitative placental dysfunctions in the context of these aneuploidies.

Detection of fetal structural anomalies in a basic first-trimester screening program for aneuploidy

OBJECTIVES

The purpose of this study was to determine whether first-trimester aneuploidy screening sonography initially performed by credentialed sonographers was useful for detecting fetal anomalies between 11 and 14 weeks' gestation.

METHODS

We conducted a retrospective cohort study of consecutive patients referred to a private ultrasound facility between January 1, 2008, and June 30, 2012, for measurement of the nuchal translucency (NT) and crown-rump length as part of a screening protocol for aneuploidy. Patients were included if there was at least 1 live fetus with a crown-rump length between 34 and 84 mm. No specific anatomic imaging protocol was followed. The presence of anomalies was based on the sonographic report and review of the medical record. The absence of anomalies was based on the report from the anatomic survey. Anomalies were categorized as lethal, major, and minor. The anomaly category and gestational age at diagnosis (≤14 versus >14 weeks) were compared.

RESULTS

An NT scan was performed on 9692 fetuses. Anatomic surveys were done on 9077 (93.7%) of these fetuses at a mean of 18 weeks' gestation. Anomalies were detected in 180 fetuses (1.8%): 50 (0.5%) at the NT scan and 130 (1.3%) at the anatomic scan. Overall, 46 of 111 fetuses (41.4%) with major or lethal anomalies were detected at the NT scan. Two suspected abnormalities at the NT scan were not present at the anatomic scan.

CONCLUSIONS

First-trimester aneuploidy screening sonography initially performed by credentialed sonographers can identify a substantial proportion of major and lethal anomalies.