The 11-13-week scan: diagnosis and outcome of holoprosencephaly, exomphalos and megacystis

Clinical practice guidelines for the care of girls and women with Turner syndrome

Turner syndrome (TS) affects 50 per 100 000 females. TS affects multiple organs through all stages of life, necessitating multidisciplinary care. This guideline extends previous ones and includes important new advances, within diagnostics and genetics, estrogen treatment, fertility, co-morbidities, and neurocognition and neuropsychology. Exploratory meetings were held in 2021 in Europe and United States culminating with a consensus meeting in Aarhus, Denmark in June 2023. Prior to this, eight groups addressed important areas in TS care: (1) diagnosis and genetics, (2) growth, (3) puberty and estrogen treatment, (4) cardiovascular health, (5) transition, (6) fertility assessment, monitoring, and counselling, (7) health surveillance for comorbidities throughout the lifespan, and (8) neurocognition and its implications for mental health and well-being. Each group produced proposals for the present guidelines, which were meticulously discussed by the entire group. Four pertinent questions were submitted for formal GRADE (Grading of Recommendations, Assessment, Development and Evaluation) evaluation with systematic review of the literature. The guidelines project was initiated by the European Society for Endocrinology and the Pediatric Endocrine Society, in collaboration with members from the European Society for Pediatric Endocrinology, the European Society of Human Reproduction and Embryology, the European Reference Network on Rare Endocrine Conditions, the Society for Endocrinology, and the European Society of Cardiology, Japanese Society for Pediatric Endocrinology, Australia and New Zealand Society for Pediatric Endocrinology and Diabetes, Latin American Society for Pediatric Endocrinology, Arab Society for Pediatric Endocrinology and Diabetes, and the Asia Pacific Pediatric Endocrine Society. Advocacy groups appointed representatives for pre-meeting discussions and the consensus meeting.

Ultrasound and magnetic resonance imaging features of fetal urogenital anomalies: A pictorial essay

This pictorial essay focuses on ultrasound (US) and magnetic resonance imaging (MRI) features of fetal urogenital anomalies. Fetal urogenital malformations account for 30%-50% of all anomalies discovered during pregnancy or at birth. They are usually detected by fetal ultrasound exams. However, when ultrasound data on their characteristics is insufficient, MRI is the best option for detecting other associated anomalies. The prognosis highly depends on their type and whether they are associated with other fetal abnormalities.

Single-center outcome analysis of 46 fetuses with megacystis after intrauterine vesico-amniotic shunting with the Somatex®intrauterine shunt

OBJECTIVES

To assess the spectrum of underlying pathologies, the intrauterine course and postnatal outcome of 46 fetuses with megacystis that underwent intrauterine vesico-amniotic shunting (VAS) with the Somatex® shunt in a single center.

METHODS

Retrospective analysis of 46 fetuses with megacystis that underwent VAS either up to 14 + 0 weeks (early VAS), between 14 + 1 and 17 + 0 weeks (intermediate VAS) or after 17 + 0 weeks of gestation (late VAS) in a single tertiary referral center. Intrauterine course, underlying pathology and postnatal outcome were assessed and correlated with the underlying pathology and gestational age at first VAS.

RESULTS

46 fetuses underwent VAS, 41 (89%) were male and 5 (11%) were female. 28 (61%) fetuses had isolated and 18 (39%) had complex megacystis with either aneuploidy (n = 1), anorectal malformations (n = 6), cloacal malformations (n = 3), congenital anomalies overlapping with VACTER association (n = 6) or Megacystis-Microcolon Intestinal-Hypoperistalsis Syndrome (MMIHS) (n = 2). The sonographic 'keyhole sign' significantly predicted isolated megacystis (p < 0.001). 7 pregnancies were terminated, 4 babies died in the neonatal period, 1 baby died at the age of 2.5 months and 34 (74%) infants survived until last follow-up. After exclusion of the terminated pregnancies, intention-to-treat survival rate was 87%. Mean follow-up period was 24 months (range 1-72). The underlying pathology was highly variable and included posterior urethral valve (46%), hypoplastic or atretic urethra (35%), MMIHS or prune belly syndrome (10%) and primary vesico-ureteral reflux (2%). In 7% no pathology could be detected postnatally. No sonographic marker was identified to predict the underlying pathology prenatally. 14 fetuses underwent early, 24 intermediate and 8 late VAS. In the early VAS subgroup, amnion infusion prior to VAS was significantly less often necessary (7%), shunt complications were significantly less common (29%) and immediate kidney replacement therapy postnatally became less often necessary (0%). In contrast, preterm delivery ≤ 32 + 0 weeks was more common (30%) and survival rate was lower (70%) after early VAS compared to intermediate or late VAS. Overall, 90% of liveborn babies had sufficient kidney function without need for kidney replacement therapy until last follow-up, and 95% had sufficient pulmonary function without need for mechanical respiratory support. 18% of babies with complex megacystis suffered from additional health restrictions due to their major concomitant malformations.

CONCLUSIONS

Our data suggest that VAS is feasible from the first trimester onward. Early intervention has the potential to preserve neonatal kidney function in the majority of cases and enables neonatal survival in up to 87% of cases. Despite successful fetal intervention, parents should be aware of the potential of mid- or long-term kidney failure and of additional health impairments due to concomitant extra-renal anomalies that cannot be excluded at time of intervention.

Basic sonographic examination of the fetal brain at 11-13 weeks' gestation: Rationale for a simple and reliable four-step technique

The widespread incorporation of first-trimester scanning between 11 and 13 weeks' gestation has shifted from the screening of chromosomal abnormalities, mainly by measuring nuchal translucency thickness and visualization of the nasal bone, to a more detailed study of the fetal anatomy leading to early detection of several structural congenital anomalies. This goal can be improved by the routine and focused sonographic assessment of specific anatomic planes and the identification of distinctive landmarks that can help disclosing a particular, non-evident condition. In this article we present the basis for a basic, early examination of the fetal brain during screening using a four-step technique, which can be readily incorporated during the first-trimester scan. The technique includes the focused visualization of the cranial contour, choroid plexuses of the lateral ventricles and midline, aqueduct of Sylvius, brainstem, fourth ventricle, and the choroid plexus of the fourth ventricle. The rationale for this approach is presented and discussed.

Turner syndrome-omphalocele association: Incidence, karyotype, phenotype and fetal outcome

OBJECTIVE

Omphalocele is known to be associated with genetic anomalies like trisomy 13, 18 and Beckwith-Wiedemann syndrome, but not with Turner syndrome (TS). Our aim was to assess the incidence of omphalocele in fetuses with TS, the phenotype of this association with other anomalies, their karyotype, and the fetal outcomes.

METHOD

Retrospective multicenter study of fetuses with confirmed diagnosis of TS. Data were extracted from a detailed questionnaire sent to specialists in prenatal ultrasound.

RESULTS

680 fetuses with TS were included in this analysis. Incidence of small omphalocele in fetuses diagnosed ≥12 weeks was 3.1%. Including fetuses diagnosed before 12 weeks, it was 5.1%. 97.1% (34/35) of the affected fetuses had one or more associated anomalies including increased nuchal translucency (≥3 mm) and/or cystic hygroma (94.3%), hydrops/skin edema (71.1%), and cardiac anomalies (40%). The karyotype was 45,X in all fetuses. Fetal outcomes were poor with only 1 fetus born alive.

CONCLUSION

TS with 45,X karyotype but not with X chromosome variants is associated with small omphalocele. Most of these fetuses have associated anomalies and a poor prognosis. Our data suggest an association of TS with omphalocele, which is evident from the first trimester.

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.

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.

Patterning of the antero-ventral mammalian brain: Lessons from holoprosencephaly comparative biology in man and mouse

Adult form and function are dependent upon the activity of specialized signaling centers that act early in development at the embryonic midline. These centers instruct the surrounding cells to adopt a positional fate and to form the patterned structures of the phylotypic embryo. Abnormalities in these processes have devastating consequences for the individual, as exemplified by holoprosencephaly in which anterior midline development fails, leading to structural defects of the brain and/or face. In the 25 years since the first association between human holoprosencephaly and the sonic hedgehog gene, a combination of human and animal genetic studies have enhanced our understanding of the genetic and embryonic causation of this congenital defect. Comparative biology has extended the holoprosencephaly network via the inclusion of gene mutations from multiple signaling pathways known to be required for anterior midline formation. It has also clarified aspects of holoprosencephaly causation, showing that it arises when a deleterious variant is present within a permissive genome, and that environmental factors, as well as embryonic stochasticity, influence the phenotypic outcome of the variant. More than two decades of research can now be distilled into a framework of embryonic and genetic causation. This framework means we are poised to move beyond our current understanding of variants in signaling pathway molecules. The challenges now at the forefront of holoprosencephaly research include deciphering how the mutation of genes involved in basic cell processes can also cause holoprosencephaly, determining the important constituents of the holoprosencephaly permissive genome, and identifying environmental compounds that promote holoprosencephaly. This article is categorized under: Congenital Diseases > Stem Cells and Development Congenital Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Molecular and Cellular Physiology Congenital Diseases > Environmental Factors.

Megacystis in the first trimester of pregnancy: Prognostic factors and perinatal outcomes

OBJECTIVE

To determine whether bladder size is associated with an unfavorable neonatal outcome, in the case of first-trimester megacystis.

MATERIALS AND METHODS

This was a retrospective observational study between 2009 and 2019 in two prenatal diagnosis centers. The inclusion criterion was an enlarged bladder (> 7 mm) diagnosed at the first ultrasound exam between 11 and 13+6 weeks of gestation. The main study endpoint was neonatal outcome based on bladder size. An adverse outcome was defined by the completion of a medical termination of pregnancy, the occurrence of in utero fetal death, or a neonatal death. Neonatal survival was considered as a favorable outcome and was defined by a live birth, with or without normal renal function, and with a normal karyotype.

RESULTS

Among 75 cases of first-trimester megacystis referred to prenatal diagnosis centers and included, there were 63 (84%) adverse outcomes and 12 (16%) live births. Fetuses with a bladder diameter of less than 12.5 mm may have a favorable outcome, with or without urological problems, with a high sensitivity (83.3%) and specificity (87.3%), area under the ROC curve = 0.93, 95% CI (0.86-0.99), p< 0.001. Fetal autopsy was performed in 52 (82.5%) cases of adverse outcome. In the 12 cases of favorable outcome, pediatric follow-up was normal and non-pathological in 8 (66.7%).

CONCLUSION

Bladder diameter appears to be a predictive marker for neonatal outcome. Fetuses with smaller megacystis (7-10 mm) have a significantly higher chance of progressing to a favorable outcome. Urethral stenosis and atresia are the main diagnoses made when first-trimester megacystis is observed. Karyotyping is important regardless of bladder diameter.

Prenatal diagnosis of exomphalos and prediction of outcome

The aim of this study was to detect a parameter for predicting prenatal complications or postnatal surgical options after detecting a fetal exomphalos. This was a retrospective analysis of prenatal diagnosis and outcome of fetuses with 41 cases of exomphalos in between 2007 and 2017, considering the measurement of ratios. The 41 fetuses with exomphalos were examined, 34 cases (82.9%) with karyotyping and 16 cases (39%) with an abnormal karyotype. Outcome of 39 cases showed 6 abortions (15.4%), 15 terminations (38.5%), an intrauterine fetal death (2.5%) and 17 alive babies (43.6%), which were grouped in two: small exomphalos (n = 6, 35.3%) and big exomphalos (n = 11, 64.7%). Maximal diameter of exomphalos/abdomen circumference-ratio (EDmax/AC-ratio) with a cut-off of 0.24 showed a better predictive value of postnatal primary closure. Exomphalos is correlated with abnormal karyotype. EDmax/AC-ratio gives the best prediction for postnatal primary closure of the defect.

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.

Assessment of the maxilla-mandible-nasion angle in normal and aneuploid foetuses in the first trimester of pregnancy

PURPOSE

This retrospective study aims to determine whether the maxilla-mandible-nasion (MMN) angle can be reliably measured in the first trimester, to describe normal ranges, and to determine if significant changes occur in foetuses with aneuploidies.

METHODS

The MMN angle was measured in stored 2D-ultrasound images of 200 normal fetal profiles between 11⁺⁰ and 13⁺⁶ weeks of gestation. Each image was analyzed by two observers at two independent time points. Bland-Altmann analysis was performed to evaluate the reliability of the measurements. Additionally, the MMN angle was measured on sonograms from 140 aneuploid foetuses.

RESULTS

The mean MMN angle in normal foetuses from 11 to 14 weeks of gestation was 15.4°. Reliability of the measurement was high when repeatedly measured by the same observer (ICC = 0.92 and 0.82) and between two observers (ICC = 0.77 and 0.63). Average MMN values in foetuses with trisomy 21, 13, and Turner syndrome were significantly higher than those measured in normal foetuses. The highest differences were observed in foetuses with trisomy 13. Among those, 62% had an MMN angle above the 95th percentile and 92% above the normal mean.

CONCLUSION

The MMN angle can be reliably measured in early pregnancy and is abnormal in about 60% of foetuses with trisomy 13.

Postnatal Management in Congenital Lower Urinary Tract Obstruction With and Without Prenatal Vesicoamniotic Shunt

Purpose: Congenital lower urinary tract obstruction (cLUTO) includes a heterogeneous group of conditions caused by a functional or mechanical outlet obstruction. Early vesicoamniotic shunting (VAS) possibly reduces the burden of renal impairment. Postpartum, pediatric urologists are confronted with neonates who have a shunt in place and a potentially impassable urethra with a narrow caliber. Early management of these patients can be challenging. Here, we would like to share the approach we have developed over time. Materials and Methods: We conducted a single-center retrospective analysis from 2016 to 2020 and included all patients diagnosed with cLUTO. Data focusing on time point and type of intervention was collected. Furthermore, patients with temporary diversion via a percutaneous VAS were selected for a more detailed review. Results: In total, 71 cases of cLUTO were identified during the study period. Within this group, 31 neonates received postnatal management and surgical intervention in our center. VAS was performed in 55% of these cases (N = 17). The postnatal treatment varied between transurethral or suprapubic catheterization and early Blocksom vesicostomy. In five infants with VAS, the urinary drainage was secured through the existing VAS by inserting a gastric tube (N = 1) or a 4.8 Fr JJ-stent (N = 4). To our knowledge, this is the first report of a stent-in-stent scheme, which can remain indwelling until the definite treatment. Conclusion: Having a secure urine drainage through a VAS allows the often premature infant to grow until definite surgery can be performed. This avoids placing a vesicostomy, which requires anesthesia.

Prenatal ultrasound findings of holoprosencephaly spectrum: Unusual associations

OBJECTIVE

The objective of this study is to evaluate the prenatal diagnosis, postnatal characteristics, and the spectrum of associated findings in fetuses with holoprosencephaly (HPE).

METHODS

Fetal neurosonograms, postnatal assessment, and chromosomal analysis were performed in a cohort of 25 fetuses with HPE.

RESULTS

The prevalence of HPE in high-risk pregnancies was 4.4:10 000. The alobar subtype was the most frequently encountered, with 17 cases (68%). Interestingly, among them, four cases (16%) presented with the rare agnathia-otocephaly complex. Chromosomal abnormalities were detected in 11 cases (44%), the most frequent being trisomy 13 in seven cases (five alobar, one semilobar, and one lobar HPE), followed by trisomy 18 in two cases with semilobar HPE. One case of alobar HPE had 45, XX, t(18;22) (q10;q10), -18p karyotyping, and one case of semilobar HPE was associated with triploidy. Facial malformations in HPE spectrum ranged from cyclopia, proboscis, and arrhinia that were associated with the alobar subtype to hypotelorism and median cleft that were frequent among the semilobar and lobar subtypes. Associated neural tube defects were identified in 12% of cases.

CONCLUSION

Our study illustrates the clinical and genetic heterogeneity of HPE and describes different chromosomal abnormalities associated with HPE.

Typical changes of ethmocephaly and holoprosencephaly in a fetus at 14 weeks of gestation

Background

This case report is to show the details of the face of a very rare ethmocephaly at 14 weeks of gestation.

Case presentation

After the regular transabdominal two-dimensional (2D) scan for nuchal translucency we could describe the following malformations: holoprosencephaly, proboscis and an abnormal face, omphalocele containing bowel, hyperechoic kidneys and megacystis. In addition, we acquired transvaginal three-dimensional (3D) ultrasound volume blocks of the fetal head, scanned with different insonation angles and stored them for later analysis. Using the multiplanar mode the volume blocks taken from the front show all details of the face: proboscis, hypotelorism, microphthalmia, cleft palate, accelerated development of the frontal bones and premature closure of the metopic suture. The volume blocks taken through the squamosal suture show all details of the fossa posterior and brain: fused thalami surrounded by the typical monoventricle, normal brain stem, elongation of anterior membranous area. Render mode shows a precise 3D image of the face. To better demonstrate the changes of the fetal face a post-mortem photo of the fetal face is included.

Conclusion

This case report can demonstarte the typical changes of ethmocephaly in the first trimester using transvaginal 3D scan.

Congenital urinary tract obstruction

Congenital bladder neck obstruction (or lower urinary tract obstruction [LUTO]) describes a heterogeneous group of congenital anomalies presenting with similar prenatal ultrasonographic findings of dilated posterior urethra, megacystis, hydronephrosis, oligohydramnios and often with associated renal dysplasia. Untreated LUTO has high rate of perinatal morbidity and mortality from associated pulmonary hypoplasia and early-onset renal failure in infancy. Ultrasonographic features and prospective fetal urinalysis may help in predicting the overall prognosis of congenital LUTO. Currently, fetal vesicoamniotic shunt (of various designs), and fetal cystoscopy and fulguration of the obstruction are potential prenatal interventions. Retrospective and prospective cohort studies and a relatively small randomized controlled trial have demonstrated these treatments may possibly improve perinatal survival. Despite this, concerns remain as to the high rates of renal impairment observed in paediatric survivors. A clinical prospective scoring/staging system may improve prenatal diagnostic criteria and case selection for fetal therapy.

Outcomes in fetuses diagnosed with megacystis: Systematic review and meta-analysis

OBJECTIVE

To explore the outcomes and prognostic factors associated with fetal megacystis (enlarged bladder).

STUDY DESIGN

The MEDLINE and EMBASE databases were searched for studies reporting on outcomes of fetal megacystis. The outcomes observed were chromosomal abnormalities, associated structural anomalies, spontaneous resolution, and survival rates. We also evaluated the potential role of fetal gender, oligohydramnios, gestational age at diagnosis, and intrauterine intervention as prenatal prognostic factors.

RESULTS

The search identified 558 articles in total, and 13 studies (1675 fetuses) were included in this systematic review. The overall incidences of chromosomal abnormalities and associated structural anomalies in fetal megacystis were 10% and 24%, respectively. Spontaneous resolution of megacystis occurred in 32% of fetuses, and 44% of fetuses were born alive and survived until the follow-up. The odds ratio of survival with oligohydramnios was 0.14, and the mean difference in gestational age at diagnosis between survival and non-survival was 3.43 weeks. No significant difference in survival rate was observed between the genders, and an intrauterine intervention did not significantly improve the prognosis.

CONCLUSIONS

A considerable proportion of fetuses with megacystis are born with a good prognosis. Oligohydramnios and lower gestational age at diagnosis are associated with worse outcomes.

Current state of MRI of the fetal brain in utero

In this article we provide an overview of fetal brain development, describe the range of more common fetal neuropathology, and discuss the relevance of in utero MR (iuMR). Although ultrasonography remains the mainstay of fetal brain imaging, iuMR imaging is both feasible and safe, but presents several challenges. We discuss those challenges, the techniques employed to overcome them, and new approaches that may extend the clinical applicability of fetal iuMR. Level of Evidence: Technical Efficacy Stage. J. Magn. Reson. Imaging 2019;49:632-646.

Evaluation of First-Trimester Physiological Midgut Herniation Using Three-Dimensional Ultrasound

INTRODUCTION

The aim of this study was to investigate the development of midgut herniation in vivo using three-dimensional (3D) ultrasonographic volume and distance measurements and to create reference data for physiological midgut herniation in ongoing pregnancies in a tertiary hospital population.

MATERIALS AND METHODS

The transvaginal 3D ultrasound volumes of 112 women, seen weekly during the first trimester of pregnancy, were obtained and subsequently analysed in a virtual reality environment. The width of the umbilical cord insertion, the maximum diameter of the umbilical cord, and the volume of midgut herniation were measured from 6 until 13 weeks gestational age (GA).

RESULTS

All parameters had a positive relation with GA, crown-rump length, and abdominal circumference. In approximately 1 of 10 volumes no midgut herniation could be observed at 9 and 10 weeks GA. In 5.0% of the fetuses the presence of midgut herniation could still be visualised at 12 weeks GA.

CONCLUSION

Reference charts for several dimensions of physiological midgut herniation were created. In the future, our data might be used as a reference in the first trimester for comparison in case of a suspected pathological omphalocele.

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.

Molecular testing in holoprosencephaly

Holoprosencephaly (HPE) is a structural brain anomaly characterized by failure of the forebrain to separate during early embryogenesis. Both genetic and environmental etiologies of HPE have been discovered over the last three decades. Traditionally, the genetic workup for HPE has been a karyotype, chromosomal microarray, and/or Sanger sequencing of select genes. The recent increased availability of next-generation sequencing has changed the molecular diagnostic landscape for HPE, associating new genes with this disorder such as FGFR1. We conducted a systematic review of the medical literature for the molecular testing of HPE for studies published in the last 20 years. We also queried known commercial diagnostic laboratories and used information on their websites to construct a list of available commercial testing. Our group released its first recommendations in 2010 and this update incorporates the technology shifts and gene discoveries over the last decade. These recommendations provide a guide for genetic diagnosis of HPE, which is paramount for patients and their families for prognosis, treatment, and genetic counseling.

Antenatal Workup of Early Megacystis and Selection of Candidates for Fetal Therapy

OBJECTIVE

To investigate the best criteria for discriminating fetuses with isolated posterior urethral valves from those theoretically not eligible for fetal treatment because of complex megacystis, high chance of spontaneous resolution, and urethral atresia.

METHODS

A retrospective national study was conducted in fetuses with megacystis detected before 17 weeks' gestation (early megacystis).

RESULTS

In total, 142 cases with fetal megacystis were included in the study: 52 with lower urinary tract obstruction, 29 with normal micturition at birth, and 61 with miscellaneous syndromal associations, chromosomal and multiple structural abnormalities (complex megacystis). Only a nuchal translucency > 95th centile, and not a longitudinal bladder diameter ≤15 mm (p = 0.24), significantly increased the risk of complex megacystis (p < 0.01). Cases with a high chance of spontaneous resolution were identified by using the cut-off of 12 mm, as demonstrated in a previous study, and the finding of an associated umbilical cord cyst carried a high-risk of urethral atresia (odds ratio: 15; p = 0.026), an unfavorable condition for antenatal treatment. An algorithm encompassing these three criteria demonstrated good accuracy in selecting fetuses theoretically eligible for fetal treatment (specificity 73%; sensitivity 92%).

CONCLUSIONS

Cases theoretically eligible for early fetal therapy are those with normal nuchal translucency, a longitudinal bladder diameter > 12 mm, and without ultrasound evidence of umbilical cord cysts.

Syndromes associated with holoprosencephaly

Holoprosencephaly (HPE) is partial or complete failure of the forebrain to divide into hemispheres and can be an isolated finding or associated with a syndrome. Most cases of HPE are associated with a syndrome and roughly 40%-60% of fetuses with HPE have trisomy 13 which is the most common etiology of HPE. Other syndromes associated with HPE include additional aneuploidies like trisomy 18 and single gene disorders such as Smith-Lemli-Opitz syndrome. There are a number of syndromes such as pseudotrisomy 13 which do not have a known molecular etiology; therefore, this review has two parts: syndromes with a molecular diagnosis and syndromes where the etiology is yet to be found. As most HPE is syndromic, this review provides a comprehensive list and description of syndromes associated with HPE that may be used as a differential diagnosis and starting point for evaluating individuals with HPE.

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.

Impact of holoprosencephaly, exomphalos, megacystis and increased nuchal translucency on first-trimester screening for chromosomal abnormalities

OBJECTIVES

To examine the prevalence of alobar holoprosencephaly, exomphalos, megacystis and nuchal translucency thickness (NT) ≥ 3.5 mm, the incidence and types of chromosomal abnormalities associated with these conditions and their overall impact on the rate of invasive testing and performance of screening at 11-14 weeks.

METHODS

This was a prospective screening study for trisomies 21, 18 and 13 by the first-trimester combined test at three maternity units in England.

RESULTS

In the study population of 108 982 singleton pregnancies, 870 (0.8%) had abnormal karyotype, including 654 (75.2%) with trisomies 21, 18 or 13 and 216 (24.8%) with other chromosomal abnormalities. The prevalence of alobar holoprosencephaly, exomphalos, megacystis and NT ≥ 3.5 mm was 1 in 2945, 1 in 419, 1 in 1345 and 1 in 119, respectively. Chromosomal abnormalities were observed in 78.4% of cases of holoprosencephaly, 40.8% of exomphalos, 18.5% of megacystis and 48.5% of those with NT ≥ 3.5 mm. The most common chromosomal abnormality associated with holoprosencephaly was trisomy 13, with exomphalos and megacystis was trisomy 18 and with increased NT was trisomy 21. Fetal karyotyping of cases with major fetal defects or increased NT would potentially detect 57% of all chromosomal abnormalities at an invasive testing rate of 1.1%.

CONCLUSION

Major fetal defects and increased NT at 11-13 weeks' gestation are associated with a high risk of chromosomal abnormalities and merit invasive fetal testing. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Effectiveness of vesicoamniotic shunt in fetuses with congenital lower urinary tract obstruction: an updated systematic review and meta-analysis

OBJECTIVE

To evaluate the effect on perinatal and postnatal survival of vesicoamniotic shunt (VAS) as treatment for fetal lower urinary tract obstruction (LUTO).

METHODS

An electronic search of Ovid MEDLINE, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews and Scopus using relevant search terms was conducted from inception to June 2015 to identify studies comparing outcomes of VAS vs conservative management for treatment of LUTO. Cohort studies and clinical trials were considered eligible. Single-arm studies and studies that did not report survival were excluded. Sample size and language were not criteria for exclusion. Two reviewers extracted independently data in a standardized form, including study characteristics and results. Primary outcomes were perinatal and postnatal survival. Secondary outcome was postnatal renal function. Data on fetal survival were expressed as odds ratio (OR) and 95% CI.

RESULTS

Of the 423 abstracts retrieved, nine studies were eligible for inclusion. These studies included 112 fetuses treated with VAS and 134 that were managed conservatively. There was heterogeneity in study design. Although the data demonstrated a difference in effect estimates between the study arms in terms of perinatal survival (OR, 2.54 (95% CI, 1.14-5.67)), there was no difference in 6-12-month survival (OR, 1.77 (95% CI, 0.25-12.71)) or 2-year survival (OR, 1.81 (95% CI, 0.09-38.03)). In addition, there was no difference in effect on postnatal renal function between fetuses that underwent intervention and those that did not (OR, 2.09 (95% CI, 0.74-5.94)).

CONCLUSIONS

Available data seem to support an advantage for perinatal survival in fetuses treated with VAS compared with conservative management. However, 1-2-year survival and outcome of renal function after VAS procedure remain uncertain. Further studies are necessary to evaluate the effectiveness of fetal intervention for LUTO based on different severity of the disease, due to the very low quality of the studies according to GRADE guidelines. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Combined screening test for trisomy 21 - is it as efficient as we believe?

OBJECTIVES

To compare two first-trimester screening strategies: traditional combined screening and the one based on ultrasound markers only. We investigated the effect of maternal age (MA) on the screening performance of both of these strategies.

METHODS

This was a prospective observational study based on a non-selected mixed-risk population of 11,653 women referred for first-trimester screening. The study population was divided in two groups: combined screening (CS) and ultrasound-based screening (US). Absolute risk was calculated to determine the influence of MA on screening performance.

RESULTS

The CS arm comprised 5145 subjects including 51 cases of trisomy 21 (T21), and the US arm comprised 5733 subjects including 87 subjects with T21. Seven hundred and seventy-five subjects were excluded from the study. For a false positive rate (FPR) of 3%, the detection rate (DR) of T21 in CS arm was 78% vs. 90% in US arm. For 5% FPR, DR was 84% and 94% in CS and US arm, respectively. MA had an influence on DR positive rates in CS: both DR and FPR for T21 increased with advance in MA.

CONCLUSIONS

The US protocol showed higher DR of T21 compared to the CS one. It may be considered as a viable alternative to CS for T21 where access to biochemical testing is limited.

Fetal megacystis: A systematic review

Fetal megacystis is variably defined and understood. The literature on fetal megacystis was systematically reviewed, focusing on prenatal diagnosis, associations and outcomes. This yielded a total of 18 primary references and eight secondary references. Fetal megacystis has an estimated first-trimester prevalence of between 1:330 and 1:1670, with a male to female ratio of 8:1. In the first trimester, megacystis is most commonly defined as a longitudinal bladder dimension of ≥7 mm. Later in pregnancy, a sagittal dimension (in mm) greater than gestational age (in weeks) + 12 is often accepted. Megacystis can be associated with a thickened bladder wall, which has been objectively defined as >3 mm. Oligohydramnios is present in approximately half of all cases. The most common underlying diagnosis is posterior urethral valves (57%), followed by urethral atresia/stenosis (7%), prune belly syndrome (4%), megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS) (1%), and cloacal anomalies (0.7%). Karyotype anomalies are found in 15%, and include trisomy 18, trisomy 13 and trisomy 21. Ultrasound imaging alone is often insufficient to enable a definitive diagnosis, although it may indicate that a specific diagnosis is more likely. Overall, about 50% of reported fetuses with megacystis are terminated, but this proportion varies considerably between countries and over time. Prognostic stratification is evolving, with the most important factors being oligohydramnios, gestational age at diagnosis, degree of bladder enlargement, renal hyperechogenicity, karyotype, and sex.

CONCLUSIONS

This review demonstrated some consensus on the ultrasound criteria for defining fetal megacystis, and illustrated the spectrum of pathologies and their relative frequencies that can cause this condition. It also underlined important associated karyotype anomalies. To progress understanding of the natural history of enlarged fetal bladders, more accurate diagnostics are required, and risk stratification needs to be refined to facilitate prenatal counseling.

First-trimester screening for trisomies 18 and 13, triploidy and Turner syndrome by detailed early anomaly scan

OBJECTIVE

To examine the performance of first-trimester ultrasound screening for trisomies 18 and 13, triploidy and Turner syndrome based on fetal nuchal translucency thickness (NT), additional fetal ultrasound markers including anatomy of the nasal bone (NB), blood flow across the tricuspid valve (TV) and through the ductus venosus (DV) and a detailed fetal anomaly scan at 11-13 weeks' gestation.

METHODS

This was a retrospective case-matched study involving pregnant women at 11-13 weeks' gestation. The study population consisted of fetuses with trisomy 18, trisomy 13, triploidy or Turner syndrome. For each fetus with an abnormal karyotype, 50 randomly selected euploid fetuses were added to the study population. In all cases, the crown-rump length and NT were measured. In addition NB, TV flow and DV flow were examined. The summed risk for trisomies 21, 18 and 13 was computed based on: first, maternal age (MA); second, MA and fetal NT; third, MA, NT and one of the markers NB, TV flow or DV flow; fourth, MA, NT and all these markers combined; fifth, MA, NT and fetal anomalies; and, finally, MA, NT, all markers and fetal anomalies.

RESULTS

The study population consisted of 4550 euploid and 91 aneuploid fetuses. Median NT was 1.8 mm in euploid fetuses and 4.8, 6.8, 1.8 and 10.0 mm in fetuses with trisomy 18, trisomy 13, triploidy and Turner syndrome, respectively. The NB, TV flow and DV flow were abnormal in 48 (1.1%), 34 (0.7%) and 99 (2.2%) euploid fetuses, respectively, and in 42 (46.2%), 31 (34.1%) and 62 (68.1%) aneuploid fetuses, respectively. At least one defect was found in 60 (1.3%) euploid and in 76 (83.5%) aneuploid fetuses. For a false-positive rate of 3%, the detection rate for screening based on MA and fetal NT was 75.8%. It increased to 84.6-86.8% when including one of the additional ultrasound markers and it was 90.1% when all three markers were included. When screening was based on MA, fetal NT and a detailed anomaly scan, the detection rate was 94.5% and increased to 95.6% with the addition of NB, TV flow and DV flow.

CONCLUSION

A detailed anomaly scan at 11-13 weeks' gestation can identify about 95% of fetuses with trisomy 18, trisomy 13, triploidy and Turner syndrome. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Intrauterine vesicoamniotic shunting for fetal megacystis

OBJECTIVE

To examine the outcome of fetuses with megacystis treated with vesicoamniotic shunting (VAS) from 14 weeks onward.

METHODS

Retrospective review of all fetuses that received VAS at two centres from 2004 to 2012.

RESULTS

53 fetuses with megacystis were included in the study. Mean gestational age at diagnosis was 16.4 weeks. Mean gestational age at first shunt placement was 17.8 weeks. The first shunt placement was performed before 16 weeks in 18 (34 %) cases. The mean number of shunts was 1.38. Dislocation occurred in 35 (66 %). TOP was performed in 21 (39.6 %), intrauterine death occurred in two (3.8 %) and spontaneous abortion in three cases (5.7 %). Of the 27 (50.9 %) live births, 17 (32.1 %) infants survived. Normal renal function was present in 10 cases, 4 have compensated renal failure and 3 infants had renal transplantation. Oligohydramnios was significantly associated with non-survival and renal insufficiency. The gestational age at VAS was neither correlated with renal function after birth nor with the survival in our cohort. Conversely, the interval between first shunt placement and delivery was positively correlated with survival and normal renal function. The gestational age at delivery was significantly higher in survivors and those born with normal renal function.

CONCLUSION

Despite intervention, the morbidity and mortality of megacystis is still high. We failed to demonstrate that early intervention is associated with an improved rate of normal renal function after birth. Oligohydramnios was the only parameter identifying fetuses with unfavourable outcome, while all other parameters were inconclusive.

Sonographic detection of central nervous system defects in the first trimester of pregnancy

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first-trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first-trimester findings. This review summarizes the current knowledge of first-trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

First Trimester Noninvasive Prenatal Diagnosis: A Computational Intelligence Approach

The objective of this study is to examine the potential value of using machine learning techniques such as artificial neural network (ANN) schemes for the noninvasive estimation, at 11-13 weeks of gestation, the risk for euploidy, trisomy 21 (T21), and other chromosomal aneuploidies (O.C.A.), from suitable sonographic, biochemical markers, and other relevant data. A database(1) (1)The dataset can become available for academic purposes by communicating directly with the authors.

First trimester fetal anatomy study and identification of major anomalies using 10 standardized scans

OBJECTIVE

to validate the use of the first trimester scan not just as a screening tool for chromosomal anomalies, but also as a method to identify the major anatomic anomalies using 10 standardized scans.

METHODS

five years of prospective study analyzing the fetal anatomy of 5924 patients with a singleton pregnancy during the first trimester screening for chromosomopathies. A check list of 10 predetermined scans had been used. The follow up consisted of two more scans in the second and third trimester, according to the local protocol, and a final evaluation of neonatal outcome at birth.

RESULTS

in the 5924 examined patients, the percentage of major malformations is 0.74%, most of all discovered in the first trimester (47.7%). The Detection Rate for the malformations related to the nervous system is about 50% and for the malformations of the abdomen, heart and skeleton is slightly lower (43.5%).

CONCLUSIONS

first trimester ultrasound using 10 standardized scans is a valid screening method for chromosomopathies and also an effective method to identify many of the major fetal anato - mical anomalies.

2014 First-trimester ultrasound forum from the Korean Society of Ultrasound in Obstetrics and Gynecology

A first-trimester ultrasound scan has become an essential part of antenatal care. The Korean Society of Ultrasound in Obstetrics and Gynecology held a first-trimester ultrasound forum on April 5, 2014. The forum aimed to present an updated review of the literature on the topic of first-trimester ultrasound in specific lectures and to host a panel discussion on several important issues regarding first-trimester scans. The forum provided evidence- and consensus-based best practice patterns for obstetricians in Korea. Here, we report the review and checklists presented from the forum.

Nichtinvasive Pränataldiagnostik

Das Ersttrimesterscreening zur Risikobestimmung für die Trisomien 21, 18 und 13 hat sich in den letzten 15 Jahren in Deutschland etabliert. Die optimale Durchführung setzt die Einhaltung bestimmter Messkriterien beim Ultraschall und bei der biochemischen Analyse voraus sowie die Benutzung evaluierter Risikoberechnungsprogramme wie dem Berechnungsprogramm PRC der Fetal Medicine Foundation Deutschland (FMF-D). Durch die neue Version des Berechnungsprogramms PRC konnten die Trisomie-21-, -18- und -13-Detektionsraten erhöht werden bei gleichzeitiger Senkung der Falsch-positiv-Raten, was einen großen Fortschritt verglichen mit der mütterlichen Altersindikation darstellt.

Durch die Analyse der zellfreien fetalen DNA aus dem mütterlichen Plasma können seit 2 Jahren aber wesentlich bessere Screeningvorhersagen getroffen werden. Über 99 % aller Trisomie-21-Schwangerschaften können mit dieser Methodik als Risikogruppe beschrieben werden. Die Falsch-positiv-Rate liegt unter 1 %. Durch diese Methode ist ein Paradigmenwechsel in der Pränataldiagnostik zu erwarten.

Diagnosis of abdominal wall defects in the first trimester

PURPOSE OF REVIEW

To review prognostic parameters reported recently in the evaluation of abdominal wall defects in the first trimester.

RECENT FINDINGS

Evaluation of abdominal wall defects in the first trimester is based principally on associated structural or chromosomal anomalies. In the case of gastroschisis, which is rarely associated with other anomalies, evaluation of prenatal or postnatal outcome is based mainly on the course of pregnancy. In the case of isolated omphalocele in the first trimester, recent studies have evaluated parameters that could help predict prenatal or postnatal outcome.

SUMMARY

We review recent studies using new parameters to diagnose abdominal wall defects in the first trimester and to provide early prenatal counselling to parents regarding prenatal and postnatal prognosis.

Biparietal diameter-to-crown-rump length disproportion in first-trimester fetuses with holoprosencephaly

OBJECTIVES

To determine whether the biparietal diameter measurement is altered in first-trimester fetuses with holoprosencephaly.

METHODS

Cases of holoprosencephaly were collected retrospectively from 4 fetal medicine centers, and first-trimester biparietal diameter measurements were reviewed. The diagnosis of holoprosencephaly was established sonographically by the detection of abnormal choroid plexus morphologic characteristics (absent "butterfly" sign) and the identification of a monoventricular cerebral cavity on axial views of the fetal brain. The proportion of fetuses with biparietal diameter measurements below the 5th percentile for crown-rump length was determined.

RESULTS

Among 45 cases of holoprosencephaly reviewed, 43 had information on both biparietal diameter and crown-rump length measurements. The biparietal diameter was below the 5th percentile for crown-rump length in 14 (32.6%) fetuses. Chromosomal analysis was available in 41; no statistically significant difference in biparietal diameter measurement between those with associated chromosomal anomalies and those without anomalies was noted. A supplementary analysis using head circumference measurement showed an even greater proportion of fetuses with holoprosencephaly with measurements below the 5th percentile for crown-rump length (18 of 42 [42.9%]).

CONCLUSIONS

One-third of first-trimester fetuses with a sonographic diagnosis of holoprosencephaly had a biparietal diameter that was smaller than expected for crown-rump length. In this subset of fetuses, the evaluation of intracranial anatomy for signs of holoprosencephaly may be more difficult to perform due to the smaller size of the brain. Therefore, the detection of a biparietal diameter below the 5th percentile as expected from crown-rump length on the first-trimester scan may be a warning sign of holoprosencephaly and should prompt a detailed examination of the intracranial anatomy.

Fetal abdominal wall defects

The most common fetal abdominal wall defects are gastroschisis and omphalocele, both with a prevalence of about three in 10,000 births. Prenatal ultrasound has a high sensitivity for these abnormalities already at the time of the first-trimester nuchal scan. Major unrelated defects are associated with gastroschisis in about 10% of cases, whereas omphalocele is associated with chromosomal or genetic abnormalities in a much higher proportion of cases. Challenges in management of gastroschisis are related to the prevention of late intrauterine death, and the prediction and treatment of complex forms. With omphalocele, the main difficulty is the exclusion of associated conditions, not all diagnosed prenatally. An outline of the postnatal treatment of abdominal wall defects is given. Other rarer forms of abdominal wall defects are pentalogy of Cantrell, omphalocele, bladder exstrophy, imperforate anus, spina bifida complex, prune-belly syndrome, body stalk anomaly, and bladder and cloacal exstrophy; they deserve multidisciplinary counselling and management.

First trimester screening for holoprosencephaly with choroid plexus morphology ('butterfly' sign) and biparietal diameter

OBJECTIVE

The aim of this study was to determine whether choroid plexus morphology ('butterfly' sign) and biparietal diameter (BPD) are effective sonographic screening tools for holoprosencephaly (HPE) in the first trimester.

METHODS

An axial view of the fetal head was obtained routinely to determine the presence of the 'butterfly' sign in pregnancies presenting for sonographic screening at 11-13 weeks of gestation. The same view was also used to obtain BPD measurements. The definitive diagnosis of HPE was established by the sonographic demonstration of an anterior cerebral monoventricular cavity and thalamic fusion.

RESULTS

During a 9-year study period, 11 068 live fetuses were screened. There were 11 cases of HPE (prevalence 1/1006); all of them were detected by demonstration of an absent 'butterfly' sign with no false-positive cases. The BPD was less than the 5th percentile in 40% of the cases.

CONCLUSIONS

The 'butterfly' sign appears to be a highly sensitive marker for HPE in the first trimester. On the other hand, BPD measurements had a lower sensitivity, implying that microcephaly is not a prominent first-trimester feature in these cases. Incorporation of the 'butterfly' sign into the first trimester anatomy scan is simple and can facilitate the identification of the vast majority of fetuses with HPE in the first trimester.

A very rare entity of diabetes insipidus associated with Edwards syndrome

Edwards syndrome is the second most commonly seen trisomy. It was first described by John Hamilton Edwards in 1960. Although most cases result in termination or foetal loss, live births have been documented in 5%. Edwards syndrome is characterized by multisystem anomalies, of which holoprosencephaly (HPE) is observed in 4-8% of cases. The clinical findings correspond to the degree of HPE malformation. Convulsions and endocrinopathies are among the severe clinical findings. The most common endocrinopathies are central diabetes insipidus (DI), hypothyroidism, hypocortisolism and growth hormone deficiency. The coexistence of holoproencephaly and DI in Edwards syndrome was discussed under the light of literature.

Trisomy 13 detection in the first trimester of pregnancy using a chromosome-selective cell-free DNA analysis method

OBJECTIVE

To assess the performance of chromosome-selective sequencing of maternal plasma cell-free DNA (cfDNA) in non-invasive prenatal testing for trisomy 13.

METHODS

Two-phase case-control study on a single plasma sample per case. The first phase was used to optimize the trisomy 13 algorithm, which was then applied to a second dataset to determine the risk score for trisomy 13 by laboratory personnel who were blinded to the fetal karyotype.

RESULTS

In the first phase, trisomy 13 risk scores were given for 11 cases of trisomy 13 and 145 euploid cases at 11-13 weeks' gestation. The test identified seven (63.6%) cases of trisomy 13 with no false positives. The trisomy 13 algorithm was subsequently modified and the trisomy 13 risk score was > 99% in all 11 cases of trisomy 13 and < 0.01% in all 145 euploid cases. In the second phase, the new algorithm was used to generate trisomy 13 risk scores for 10 cases of trisomy 13 and 1939 euploid cases. The trisomy 13 risk scores were > 99% in eight (80.0% (95% confidence interval (CI), 49.0-94.3%)) cases of trisomy 13. In the 1939 euploid cases the risk score for trisomy 13 was < 0.01% in 1937 (99.9%), 0.79% in one, and > 99% in one. Therefore, at the predefined risk cut-off of 1% for classifying a sample as high or low risk, the false-positive rate (FPR) was 0.05% (95% CI, 0.0-0.3%).

CONCLUSIONS

Chromosome-selective sequencing of cfDNA can detect the majority of cases of trisomy 13 at an FPR of less than 0.1%.