Evaluation of the prenatal diagnosis of neural tube defects by fetal ultrasonographic examination in different centres across Europe

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.

The science of uncertainty guides fetal-neonatal neurology principles and practice: diagnostic-prognostic opportunities and challenges

Fetal-neonatal neurologists (FNNs) consider diagnostic, therapeutic, and prognostic decisions strengthened by interdisciplinary collaborations. Bio-social perspectives of the woman's health influence evaluations of maternal-placental-fetal (MPF) triad, neonate, and child. A dual cognitive process integrates "fast thinking-slow thinking" to reach shared decisions that minimize bias and maintain trust. Assessing the science of uncertainty with uncertainties in science improves diagnostic choices across the developmental-aging continuum. Three case vignettes highlight challenges that illustrate this approach. The first maternal-fetal dyad involved a woman who had been recommended to terminate her pregnancy based on an incorrect diagnosis of an encephalocele. A meningocele was subsequently identified when she sought a second opinion with normal outcome for her child. The second vignette involved two pregnancies during which fetal cardiac rhabdomyoma was identified, suggesting tuberous sclerosis complex (TSC). One woman sought an out-of-state termination without confirmation using fetal brain MRI or postmortem examination. The second woman requested pregnancy care with postnatal evaluations. Her adult child experiences challenges associated with TSC sequelae. The third vignette involved a prenatal diagnosis of an open neural tube defect with arthrogryposis multiplex congenita. The family requested prenatal surgical closure of the defect at another institution at their personal expense despite receiving a grave prognosis. The subsequent Management of Myelomeningocele Study (MOMS) would not have recommended this procedure. Their adult child requires medical care for global developmental delay, intractable epilepsy, and autism. These three evaluations involved uncertainties requiring shared clinical decisions among all stakeholders. Falsely negative or misleading positive interpretation of results reduced chances for optimal outcomes. FNN diagnostic skills require an understanding of dynamic gene-environment interactions affecting reproductive followed by pregnancy exposomes that influence the MPF triad health with fetal neuroplasticity consequences. Toxic stressor interplay can impair the neural exposome, expressed as anomalous and/or destructive fetal brain lesions. Functional improvements or permanent sequelae may be expressed across the lifespan. Equitable and compassionate healthcare for women and families require shared decisions that preserve pregnancy health, guided by person-specific racial-ethnic, religious, and bio-social perspectives. Applying developmental origins theory to neurologic principles and practice supports a brain health capital strategy for all persons across each generation.

Fetal Hands: A Comprehensive Review of Prenatal Assessment and Diagnosis Over the Past 40 Years

Fetal skeletal dysplasias involving limbs and hands are rare congenital malformations. Prenatal two-dimensional ultrasound diagnosis of fetal limb defects has a sensitivity of about 30%; however, an increased detection rate may be obtained using three-dimensional (3-D) ultrasound in the rendering mode. 3-D ultrasound may be used as a complementary method providing additional information. Currently, magnetic resonance imaging (MRI), with the emergence of ultrafast imaging techniques and new sequences, allows for better diagnosis of several fetal skeletal dysplasias such as limb reduction defects and neuromuscular disorders. 3-D volumetric images from ultrasound or MRI scan data allow 3-D ultrasound reconstructions of virtual/physical models, and virtual reality can help researchers to improve our understanding of both normal and abnormal fetal limb/hand anatomy. In this article, we review the embryological development of fetal hands and their main anomalies including prenatal diagnostic methods, genetic counseling, the role of orthopedic and plastic surgery reconstruction, and new perspectives in fetal surgery.

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.

Global prevalence of congenital anencephaly: a comprehensive systematic review and meta-analysis

Background

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Timely preventive measures can be taken by knowing the exact prevalence of this common neural tube defect; thus, carried out through systematic review and meta-analysis, the present study was conducted to determine the worldwide prevalence, incidence and mortality of anencephaly.

Methods

Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. The I² test was used to calculate study heterogeneity, and Begg and Mazumdar rank correlation tests were employed to assess the publication bias. Data were analyzed by Comprehensive Meta-Analysis software (Version 2).

Results

In this study, the statements of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) were used. In the first stage, 1141 articles were found, of which 330 duplicate studies were omitted. 371 articles were deleted based on the inclusion and exclusion criteria by reviewing the title and abstract of the study. 58 articles were removed by reviewing the full text of the article because it was not relevant to the research. 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births).

Conclusion

The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

Anencephaly is a fatal congenital anomaly characterized by the absence of brain hemispheres and cranial arch. Cochran’s seven-step instructions were used as the guideline. Having determined the research question and inclusion and exclusion criteria, we studied MagIran, SID, Science Direct, WoS, Web of Science, Medline (PubMed), Scopus, and Google Scholar databases. Moreover, the search strategy in each database included using all possible keyword combinations with the help of “AND” and “OR” operators with no time limit to 2021. Out of 1141 initial articles found, and after excluding repetitive ones in various databases and those irrelevant to inclusion criteria, 360 studies with a sample size of 207,639,132 people were considered for the meta-analysis. Overall estimate of the prevalence, incidence and attenuation of anencephaly worldwide were 5.1 per ten thousand births (95% confidence interval 4.7–5.5 per ten thousand births), 8.3 per ten thousand births (95% confidence interval 5.5–9.9 per ten thousand births), 5.5 per ten thousand births (95% confidence interval 1.8–15 per ten thousand births) respectively the highest of which according to the subgroup analysis, belonged to the Australian continent with 8.6 per ten thousand births (95% confidence interval 7.7–9.5 per ten thousand births). The overall prevalence of anencephaly in the world is significant, indicating the urgent need for preventive and treating measures.

[The ethics of fetal myelomeningocele surgery]

Fetal myelomeningocele surgery was introduced in France in 2014. Developments in prenatal diagnosis of neural tube defects have accompanied the development of prenatal diagnosis. This fetal surgery represents one of the three possible care paths for pregnant women faced with this prenatal diagnosis. The ethical issues of this fetal surgery are discussed and in particular regarding prenatal counselling and patient autonomy of choice.

Brain malformations and cognitive performance in spina bifida

AIM

To systematically characterize radiological features of patients with spina bifida, their relationship to cognitive function, and differences between spina bifida aperta (SBA) and spina bifida occulta (SBO).

METHOD

In a retrospective study of 265 patients (117 females, 148 males; median age at imaging 11y, range 1-47y; SBA n=206, SBO n=59), the radiological phenotype was assessed through magnetic resonance imaging (MRI) (SBA n=171, SBO n=59). In 126 patients (SBA n=116, SBO n=10) Kaufman Assessment Battery for Children (KABC) or Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) and Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) were performed.

RESULTS

Patients with spina bifida show numerous brain malformations, always present for SBA but rarely for SBO. The most frequent brain malformations in SBA included abnormal corpus callosum (69%), hypoplastic pons (50%), and hypoplastic mesencephalon (20%). Cognitive total IQ scores were below average in 44% (KABC) to 49% (WISC-IV) of children with SBA, while almost all children with SBO scored at least average. Stenogyria (p=0.006), pons (p=0.003), and mesencephalon hypoplasia (p=0.01) correlated with lower total IQ score and verbal comprehension. Various brain malformations correlate significantly with several cognitive domains, while lesion level only correlates with processing speed.

INTERPRETATION

IQ scores were significantly lower in patients with SBA than in patients with SBO. Verbal competence, perceptual reasoning, and working memory were significantly impaired for SBA and correlated with stenogyria and abnormalities of the midbrain and corpus callosum.

WHAT THIS PAPER ADDS

Brain malformations occur more frequently in spina bifida aperta (SBA) than in spina bifida occulta (SBO). Cognitive impairment is less frequent in SBO. Hydrocephalus, stenogyria, midbrain, and corpus callosum abnormalities are associated with lower cognitive function. Difference in prognosis in SBO versus SBA can alter prenatal counselling.

Fetal surgery for occipital encephalocele

OBJECTIVE

In this study, the authors retrospectively reviewed two cohorts of patients with occipital encephalocele (OE) and demonstrate the technical aspects of an innovative and unprecedented method for fetal OE correction.

METHODS

This was a cross-sectional retrospective study of 22 patients who underwent surgery from July 2012 to July 2018. The inclusion criteria for participants were a gestational age between 19 weeks and 27 weeks, a maternal age ≥ 18 years, a normal fetal karyotype, the presence of microcephaly, and a cystic hernial sac with the cystic component accounting for more than 80% of the total volume, which was larger than 10 ml. The fetuses with OE and microcephaly underwent intrauterine repair. The exclusion criteria were the presence of a fetal anomaly not associated with OE, chromosomopathy, presence of the brainstem inside the hernial sac or venous sinuses inside the herniated content, the risk of premature birth, placenta previa, and maternal conditions that would constitute an additional risk for fetal and maternal health, as well as refusal for fetal surgery. The authors reviewed the potential for microcephaly reversal and the long-term neurocognitive development.

RESULTS

The authors report the cases of 9 fetuses with OE and microcephaly who underwent intrauterine OE repair at gestational ages of less than 27 weeks (fetal group). One case selected for fetal surgery also presented with placental abruption. All patients who underwent the fetal operation had microcephaly reversal, and 3 patients required ventriculoperitoneal shunting in the 1st year of life. The authors reviewed the cases of 12 patients who underwent postnatal repair. In 10 cases, fetal surgery was refused (postnatal group), and in 2 cases, the inclusion criteria for fetal surgery were not met. The authors evaluated the neurocognitive development of the patients with the Bayley Scales of Infant Development II. The median score for the fetal group was 98.7, and that for the postnatal group was 27.8.

CONCLUSIONS

The intrauterine repair of OE may stop the progression of encephalocele sac herniation and result in microcephaly reversal. The fetal group had a better cognitive outcome than the postnatal group. The technique required to correct this defect is feasible for those with previous experience in the correction of fetal myelomeningocele. However, more studies are needed to ensure the efficacy of this procedure.

Fetal surgery for open spina bifida

KEY CONTENT

Spina bifida is a congenital neurological condition with lifelong physical and mental effects.Open fetal repair of the spinal lesion has been shown to improve hindbrain herniation, ventriculoperitoneal shunting, independent mobility and bladder outcomes for the child and, despite an increased risk of prematurity, does not seem to increase the risk of neurodevelopmental impairment.Open fetal surgery is associated with maternal morbidity.Surgery at our institution is offered and performed according to internationally agreed criteria and protocols.Further evidence regarding long-term outcomes, fetoscopic repair and alternative techniques is awaited.

LEARNING OBJECTIVES

To understand the clinical effects, potential prevention and prenatal diagnosis of spina bifida.To understand the rationale and evidence supporting the benefits and risks of fetal repair of open spina bifida.To understand the criteria defining those who are likely to benefit from fetal surgery.

ETHICAL ISSUES

The concept of the fetus as a patient, and issues surrounding fetal death or the need for resuscitation during fetal surgery.The associated maternal morbidity in a procedure performed solely for the benefit of the fetus/child.The financial implications of new surgical treatments.

Antenatal management of fetal neurosurgical diseases

The advance in the imaging tools during the pregnancy (ultrasound and magnetic resonance) allowed the early diagnose of many fetal diseases, including the neurological conditions. This progress brought the neurosurgeons the possibility to propose treatments even before birth. Myelomeningocele is the most recognized disease that can be treated during pregnancy with a high rate of success. Additionally, this field can be extended to other conditions such as hydrocephalus and encephaloceles. However, each one of these diseases has nuances in the diagnostic evaluation that should fit the requirements to perform the fetal procedure and overbalance the benefits to the patients. In this article, the authors aim to review the neurosurgical aspects of the antenatal management of neurosurgical conditions based on the experience of a pediatric neurosurgery center.

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.

Timing of detection of anencephaly in The Netherlands

OBJECTIVE

The objective of this study is to assess the gestational age at detection and prevalence of anencephaly in the North of The Netherlands over a 5-year period.

METHODS

A case list of all cases of anencephaly from two fetal medicine units was compiled. Cases were included if the estimated due date was between 1 August 2008 and 31 July 2013.

RESULTS

Overall prevalence of anencephaly was 5.4 per 10.000 pregnancies (n = 110). The majority of cases (69%) was detected before 18 weeks' gestation. Factors determining successful early diagnosis were competence level of the sonographers, with a significantly higher detection rate when scans were performed by a sonographer licensed by the Fetal Medicine Foundation (FMF) for nuchal translucency measurement (p = 0.001), and gestational age at or beyond 11 weeks of gestation (p = 0.024).

CONCLUSION

Improving detection of anencephaly in the first trimester requires ultrasound screening at or after 11 weeks of gestation, performed by experienced sonographers trained in recognizing fetal anomalies. Sonographers should be instructed that the goal of the first trimester scan is not only to measure nuchal translucency thickness but also to exclude major anomalies.

Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis

BACKGROUND

Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region's food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation.

OBJECTIVES

We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population.

SEARCH METHODS

An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts.

SELECTION CRITERIA

Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party.

DATA COLLECTION AND ANALYSIS

We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as "mandatory" or "voluntary" folic acid fortification according to each country's folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food Fortification Initiative). We determined study quality on the basis of sample representativeness, standardization of data collection and birth defect assessment, and statistical analyses. We analyzed study-level period prevalence estimates by using a random effects model (α level of < 0.05) for all meta-analyses. We stratified pooled period prevalence estimates by birth population, fortification status, and continent.

RESULTS

Of 4078 studies identified, we included 179 studies in the systematic review and 123 in a meta-analysis. In studies of live births (LBs) alone, period prevalences of spina bifida were (1) lower in geographical regions with mandatory (33.86 per 100,000 LBs) versus voluntary (48.35 per 100,000 LBs) folic acid fortification, and (2) lower in studies of LBs, stillbirths, and terminations of pregnancy in regions with mandatory (35.22 per 100,000 LBs) versus voluntary (52.29 per 100,000 LBs) fortification. In LBs, stillbirths, and terminations of pregnancy studies, the lowest pooled prevalence estimate was in North America (38.70 per 100,000). Case ascertainment, surveillance methods, and reporting varied across these population-based studies.

CONCLUSIONS

Mandatory legislation enforcing folic acid fortification of the food supply lags behind the evidence, particularly in Asian and European countries. This extensive literature review shows that spina bifida is significantly more common in world regions without government legislation regulating full-coverage folic acid fortification of the food supply (i.e., Asia, Europe) and that mandatory folic acid fortification resulted in a lower prevalence of spina bifida regardless of the type of birth cohort. African data were scarce, but needed, as many African nations are beginning to adopt folic acid legislation.

Sonographic spectrum of first-trimester fetal cephalocele: review of 35 cases

OBJECTIVE

To describe the sonographic features of fetal cephalocele diagnosed at the time of first-trimester ultrasound screening for aneuploidy.

METHODS

This was a retrospective review of cases of cephalocele diagnosed in the first trimester at four fetal medicine referral centers. Once diagnosis was suspected, a transvaginal ultrasound examination was offered to improve depiction of the cranial defect and enhance examination of fetal anatomy, with special attention given to the location, size and content of defects. To assure consistency in diagnosis, representative pictures and videoclip sequences of the cranial defect were obtained and reviewed by at least two authors. Cases were classified and compared with the assessment made at diagnosis.

RESULTS

Of the 35 affected fetuses identified, 33 were of a singleton pregnancy and two were of twin pregnancies in which the other fetus was unaffected. The lesion was classified as a cranial meningocele in 13 (37%) cases and as an encephalocele in 22 (63%). The bone defect was occipital in 27 (77%), frontal in three (9%), parietal in three (9%) and non-classifiable in two (6%). Twelve (34%) were considered as small in size, 11 (31%) as medium and 12 (34%) as large. There were no reported cases of aneuploidy; however, four (11%) cases were associated with Meckel-Gruber syndrome, two (6%) with a disruptive syndrome and one (3%) with skeletal dysplasia. Eight (23%) pregnancies were lost to follow-up. Parents opted for termination of pregnancy in 21 of the 27 remaining cases and, of the six ongoing pregnancies, four patients miscarried or the fetus died in utero during the second trimester, one liveborn infant died shortly after delivery and one underwent neonatal surgery for an isolated cranial meningocele and is currently doing well.

CONCLUSIONS

First-trimester sonographic diagnosis of cephalocele is accomplished easily with a detailed examination of the skull contour at the time of routine assessment of the axial and sagittal views of the head for measurement of the biparietal diameter and nuchal translucency, respectively. However, the sonographic features are highly variable. A significant proportion of cases are associated with genetic or disruptive syndromes. Prenatal diagnosis of cephalocele in the first trimester was associated with a high rate of termination of pregnancy and early intrauterine fetal demise. Only one fetus in this series survived and is neurologically intact; therefore, the prognosis of this condition remains poor.

Myelomeningocele (open spina bifida) - surgical management

Myelomeningocele has been recognized since ancient times although written descriptions began not before the 17th century. Among all serious congenital malformations, myelomeningocele is unique that is has a steady and considerable prevalence while being compatible with life. It has a dismal prognosis when left untreated where virtually all die within the first year while aggressive treatment have a profound effect on survival and quality of life. Effective surgical treatment became possible parallel to the treatment of hydrocephalus in the late 1950s. Advent of the shunt systems undoubtedly changed the morbidity and mortality rates due to associated hydrocephalus. Aggressive and effective treatment improved survival rates but also those suffering physical and mental disabilities have increased as well. Ethical and socioeconomic concerns have led to proposal for selective treatment criteria which have raised arguments on medical and ethico-legal rounds. After the swing of the pendulum between early treatment in all affected children and selective treatment of those who fulfilled the criteria for good prognosis, early myelomeningocele repair is practiced widely unless the infant is critically ill.Incidence of myelomeningocele has been decreasing especially in the Western world, partly due to prenatal diagnosis and elective terminations, dietary folate supplementation. Still, it is the most common central nervous system malformation and one of the leading causes of paraplegia, worldwide. Unfortunately, gains in the management of myelomeningocele have been mainly on antenatal diagnosis and prevention while efforts on understanding its cause, mechanisms involved are still tentative. Concerning the surgical management, no revolutionary modification improving outcome has been introduced unlike other fields of neurosurgery.Medical management of a child with myelomeningocele requires a lifelong effort of several disciplines including urology, orthopedics physical and social therapy besides neurosurgery. The initial and probably the most crucial step begin with proper repair of the lesion. The aim of surgery, with its simplest definition should be towards maintaining the medical condition of the newborn. In other words, consequences of an open spinal cord segment with associated malformations have to be avoided with appropriate measures. Comparable to the surgical treatment of any congenital malformation, myelomeningocele repair consist of reversing the failed steps of normal neural tube closure. This requires a thorough understanding of the normal and abnormal embryological sequence of events in formation of the spinal cord. Although the purpose of this chapter is to describe the basic concepts and technique of myelomeningocele repair, contemporary information and progress on epidemiology, and etiology and embryology is presented with discussion of controversial issues regarding the selection process, optimal time for surgery and technical modifications.

Cranial and cerebral signs in the diagnosis of spina bifida between 18 and 22 weeks of gestation: a German multicentre study

OBJECTIVE

The aim of this article is to study secondary cranial signs in fetuses with spina bifida in a precisely defined screening period between 18 + 0 and 22 + 0 weeks of gestation.

METHOD

On the basis of retrospective analysis of 627 fetuses with spina bifida, the value of indirect cranial and cerebral markers was assessed by well-trained ultrasonographers in 13 different prenatal centres in accordance with the ISUOG (International Society of Ultrasound in Obstetrics and Gynecology) guidelines on fetal neurosonography.

RESULTS

Open spina bifida was diagnosed in 98.9% of cases whereas 1.1% was closed spina bifida. Associated chromosomal abnormalities were found in 6.2%. The banana and lemon signs were evident in 97.1% and 88.6% of cases. Obliteration of the cisterna magna was seen in 96.7%. Cerebellar diameter, head circumference and biparietal diameter were below the 5th percentile in chromosomally normal fetuses in 72.5%, 69.7% and 52%, respectively. The width of the posterior horn of the lateral ventricle was above the 95th percentile in 57.7%. The secondary cranial and cerebral signs were dependent on fetal chromosome status and width of the posterior horn. Biparietal diameter was also dependent on the chromosome status with statistical significance p = 0.0068. Pregnancy was terminated in 89.6% of cases.

CONCLUSION

In standard measuring planes, lemon sign, banana sign and an inability to image the cistern magna are very reliable indirect ultrasound markers of spina bifida. © 2014 John Wiley & Sons, Ltd.

Prenatal diagnosis of open spina bifida in Emilia-Romagna

OBJECTIVE

To report recent data on the epidemiology of pregnancies affected by open spina bifida in the Emilia-Romagna region of Italy.

METHODS

All cases of open spina bifida diagnosed in the Emilia-Romagna region between 2001 and 2011 and reported to the IMER regional registry were included in the study group. The pregnancy outcome was retrospectively assessed.

RESULTS

In the study period out of 390,978 babies born in Emilia-Romagna 126 cases of open spina bifida were reported to the IMER registry, resulting in a global prevalence of 3.2 per 10,000 births. Prenatal diagnosis was achieved in the vast majority of these cases (105/126; 83.3%) and in a great proportion of those women (85/105; 80.9%) who opted for termination of pregnancy.

CONCLUSIONS

In a wide region of northern Italy where ultrasound anomaly scan is routinely offered to the general population, the vast majority of cases of open spina bifida are diagnosed antenatally and terminated electively.

Neural Tube Defects: The Experience of the Registry of Congenital Malformations of Alsace, France, 1995-2009

Context and Objective: Considering the lack of accurate and up-to-date information available about neural tube defects (NTDs) in France, the purpose of this study was to review clinical and epidemiological data of NTDs and to evaluate the current efficiency of prenatal diagnosis in Alsace (northeastern France). Methods: A population-based retrospective study was performed from data of the Registry of Congenital Malformations of Alsace between 1995 and 2009. Data were analyzed as a whole and according to the anatomical type of the malformation (anencephaly, cephalocele and spina bifida). Statistical analyses were carried out using the Statistical Package for the Social Sciences. Results: 272 NTDs were recorded divided in 113 cases of anencephaly (42%), 35 cases of cephalocele (13%) and 124 cases of spina bifida (45%). The total prevalence at birth of 14/10,000 (95% CI 13-16) was stable throughout the reporting period. A chromosome abnormality was identified in 27 cases (12% of all karyotyped cases). NTDs were prenatally diagnosed by ultrasound in 88% of the cases. The mean age upon prenatal diagnosis slightly declined during the 15-year period, significantly for spina bifida only. The global rate of terminations of pregnancy following prenatal diagnosis was 97% (230/238). Conclusion: This work constitutes a unique population-based study providing accurate and specific up-to-date data from a unique center over a longer period (1995-2009). The most important information concerns the high and stable prevalence, which calls into question the efficiency of the primary prevention by folic acid supplementation and the efficiency of prenatal diagnosis.

Prenatal imaging of occipital encephaloceles

INTRODUCTION

This retrospective study aims to describe systematically the fetal cerebral MR morphology in cases with occipital meningoencephaloceles using standard and advanced fetal MRI techniques.

MATERIAL AND METHODS

The 1.5-tesla MR examinations (T1- and T2-weighted imaging, echo planar imaging, EPI, diffusion-weighted imaging, DWI) of 14 fetuses with occipital/parietal meningoencephaloceles were retrospectively analyzed for the classification of anatomic characteristics. A diffusion tensor sequence was performed in 5 cases.

RESULTS

In 9/14 cases the occipital lobes were entirely or partially included in the encephalocele sac. Typical features of Chiari III malformation were seen in 6/14 cases. The displaced brain appeared grossly disorganized in 6/14. The brainstem displayed abnormal 'kinking'/rotation (3/14), a z-shape (1/14) and/or a molar tooth-like configuration of the midbrain (3/14). Tractography revealed the presence and position of sensorimotor tracts in 5/5 and the corpus callosum in 3/5. DWI was helpful in the identification of a displaced brain (in 8/9). EPI visualized the anatomy of draining cerebral veins in 7/9 cases. Clinical (9/14) and MRI (7/14) follow-up data are presented.

DISCUSSION

Encephaloceles show a wide range of morphological heterogeneity. Fetal MRI serves as an accurate tool in the visualization of brainstem, white matter pathway and cerebral venous involvement and facilitates the detection of specific underlying syndromes such as ciliopathies.

Prenatal prediction of need for ventriculoperitoneal shunt in open spina bifida

OBJECTIVE

To investigate whether the need for ventriculoperitoneal shunting in neonates with open spina bifida can be predicted prenatally.

METHODS

This was a retrospective cohort study of all fetuses with open spina bifida identified at a single referral center between 1998 and 2012. Ultrasound records were reviewed and outcomes were ascertained from maternal, neonatal and pediatric records. The performance of screening was determined by receiver-operating characteristics (ROC) curve analysis.

RESULTS

We identified 124 cases of isolated open spina bifida, of which 48 were liveborn. Detailed postnatal follow-up was available for 39 cases, with an average follow-up time of 3.6 years. A shunt was inserted in 22 (56.4%) cases. The width of the posterior horn of the lateral ventricle (Vp) and the ratio between its width and that of the cerebral hemisphere (Vp/H) at diagnosis were significantly greater in cases that required a shunt compared with those that did not subsequently require a shunt (Vp: median 12.4 mm vs 7.7 mm, P < 0.001, and Vp/H: median 0.54 vs 0.33, P < 0.001, respectively). Similarly, at the last scan before delivery, Vp and Vp/H were significantly higher in those requiring a shunt (Vp: median 23.1 mm vs 8.2 mm, P < 0.001; and Vp/H: 0.54 vs 0.21, P < 0.001, respectively). Using Vp and Vp/H at the initial assessment, the rates of detection of fetuses requiring a shunt postnatally were 68.2% and 86.4% for a false-positive rate of 13%, with positive likelihood ratios of 6 and 7, respectively. All fetuses with a Vp of ≥ 12 mm or a Vp/H of ≥ 0.6 at the time of diagnosis required postnatal shunt insertion (positive predictive value = 100%).

CONCLUSIONS

In cases with open spina bifida the need for a postnatal shunt can be predicted prenatally. This novel observation should be useful in the prediction of outcome and therefore for accurate prenatal counseling and triaging cases for fetal surgery.

Maternal reporting of prenatal ultrasounds among women in the National Birth Defects Prevention Study

BACKGROUND

Increased availability and usage of ultrasound screening have led to improved identification of fetal structural abnormalities prenatally. Few population-based studies have been published on prenatal detection for structural birth defects in the United States. The aim of this study is to determine the frequency of maternal reporting of abnormal prenatal ultrasounds for selected birth defects and to investigate associated maternal characteristics.

METHODS

Participants included 4013 mothers enrolled in the National Birth Defects Prevention Study who carried a fetus with at least one of 14 structural birth defects between 1997 and 2004. Frequencies of abnormal prenatal ultrasounds were based on maternal report and computed for isolated and multiple defects. Associations between maternal characteristics and abnormal prenatal ultrasounds were assessed using logistic regression.

RESULTS

Overall, 46% of participants reported an abnormal ultrasound. Infants with omphalocele, anencephaly, gastroschisis, and renal agenesis were more likely to have abnormal prenatal ultrasounds than those with cleft and limb abnormalities. Hispanic women were less likely to report abnormal prenatal ultrasounds of birth defects than Caucasians, as were women who had a body mass index ≥ 30 kg/m(2) compared with those with a normal body mass index.

CONCLUSION

Of the 14 selected birth defects in this study, less than half were reported by mothers of affected infants to have had an abnormal ultrasound during pregnancy. The frequency of reporting abnormal prenatal ultrasounds varies by type of defect, maternal race/ethnicity, and maternal body mass index status.

Spinal dysraphism

To review the clinical features and current understanding of spina bifida with an emphasis on the Indian Scenario. Selected articles and current English language texts were reviewed. The authors experience was also reviewed and analysed. Spina bifida is a common congenital anomaly encompassing a wide spectrum of neural tube defects.It is broadly classified as spina bifida aperta and occulta. With the prenatal screening, the incidence of aperta is gradually declining, whereas the detection of occulta has increased with the advent of magnetic resonance imaging. Over the years, the understanding of pathophysiology has made a significant changein the management of these anomalies. Early detection and complete correction can significantly reduce the neurological disability. This article is an overview of spina bifida with a special emphasis on Indian scenario.

Investigation of ultrasound screening efficiency for neural tube defects during pregnancy in rural areas of China

OBJECTIVES

To understand the uptake and efficacy of ultrasound screening for neural tube defects (NTDs) during pregnancy, and the outcomes when NTDs were detected in rural areas of China.

STUDY DESIGN

Prevalence study.

METHODS

Four hundred and twenty-four women who delivered or gestated babies/fetuses with NTDs were selected at random in 20 counties of two provinces of China from March 2008 to January 2009. The uptake of ultrasound screening, NTD detection rate and termination of pregnancy (TOP) rate were calculated and analyzed. Generalized estimating equations were employed to control for potential confounding factors.

RESULTS

The uptake of ultrasound screening was 98.8%. Among the study subjects, 361 (85.1%) NTDs were detected and 63 (14.9%) were not detected by prenatal ultrasound screening. The total detection rate was 43.3% (15.6%, 49.6% and 52.2% in the first, second and third trimesters, respectively; P < 0.05). Taking the possibility of NTD detection in the first trimester as 1.0, the possibilities in the second and third trimesters were 10.9 [95% confidence interval (CI) 6.5-18.3] and 25.2 (95% CI 13.3-47.6), respectively. The detection rate at the township health centres (THCs), family planning centres (FPCs), maternal and child care service centres (MCSCs) and hospitals was 24.5%, 29.1%, 53.6% and 78.1%, respectively (P < 0.05). Taking the possibility of NTD detection at THCs as 1.0, the possibilities at FPCs, MCSCs and hospitals were 0.9 (95% CI 0.5-1.6), 3.4 (95% CI 1.9-6.1) and 2.1 (95% CI 1.3-3.4), respectively. Three hundred and fifty-five (98.3%) of the 361 NTDs detected at prenatal ultrasound screening ended in TOP.

CONCLUSIONS

The uptake of ultrasound screening was satisfactory, but the NTD detection rate was low. Ultrasound screening did not play its full role in the secondary prevention of NTDs in the study areas. Medical institutions in rural areas in China need to improve their ultrasound screening skills in order to increase the efficacy of NTD control.

Non Vascular Congenital Brain Malformations. An MR Study of 5000 Patients

Central nervous system (CNS) malformations are frequently severe and often fatal. Diagnosis during pregnancy is of fundamental importance for a correct clinical evaluation and pharmacological management or, where possible, surgery. Modern imaging technology, pre and post-natal ultrasound scans, but above all magnetic resonance (MR) imaging have revolutionized the diagnostic study of cerebral malformations. In particular, MR provides images of the various brain sections by means of a multidisciplinary non invasive study that today is particularly rapid. MR allows an accurate assessment of cortical development, normal myelinization and the evolution of malformations. We report here our experience with MR carried out after birth on 5000 patients for the study of non vascular cortical anomalies. In only one case was the examination carried out during pregnancy, following ultrasound investigations that showed a developmental anomaly of the corpus callosum. We confirmed 112 malformations with an incidence of 2.24%, greater in males and affecting principally the anatomy of the supratentorial encephalic structures. These cases were selected and MR was carried out based on the clinical picture present at the time of the examination or a suspected diagnosis formulated following ultrasound. The ultrasound investigations were carried out principally in the obstetrics department; only a few were carried out in our unit, together with most of the postnatal ultrasound scans. The percentage of the various malformations was higher than those reported in the literature.

[The ultrasonographic diagnosis of fetal encephalocele at 13th gestational week]

BACKGROUND

Encephalocele presents a rare anomaly of central nervous system, developed as a consequence of neural tube closing defect during early embrional development, and it is described by a baggy formation which prolaborates through the pores of the scull, filled with brain tissue, cerebrospinal liquor and entwined with meninges. According to literature search, until this day, the earliest it can be ultrasonically detected is the 13th gestation week, with the appliance of three-dimensional ultrasound.

CASE REPORT

We presented 25 years old patient, ultrasonically diagnosed with occipital fetal encephalocela at the 13th gestation week. A gestation sack was located in the right uteral corn of the two-corned uterus with one cervix. The diagnosis was confirmed also by trippled value of alpha-fetoprotein in maternal serum: 75.98 IU/mL.

CONCLUSION

Ultrasonic examination is the method of choice for prenatal detection of a fetal anomaly. It is possible to diagnose encephalocele if it prominates above the limits of the scull.

Dyslipidemia in pregnancy may contribute to increased risk of neural tube defects -a pilot study in north Indian population

Neural tube defects are congenital structural abnormalities of the brain and vertebral column resulting from improper or non-timely closure of the neural tube. Prevalence of neural tube defects is reported to be higher among women with diabetes mellitus and obesity. This study was designed to investigate the relation between the presence of dyslipidemia in antenatal patients and the risk of fetal neural tube defects. The present study was an observational, cross-sectional study involving 129 pregnant women in 16 to 18 weeks gestation period. Of these, 80 women had normal pregnancies and 49 were clinically high-risk cases for neural tube defects. Fasting blood samples were analyzed for blood sugar and lipid profile by enzymatic assay and alpha-fetoprotein levels using Enzyme Immunoassay. Alpha-fetoprotein (AFP) values were converted to Multiples of Median (MoM) appropriate for the gestational age. Based on AFP values, women were labeled as screen negative (AFP <2 MoM, n= 102) and screen positive (AFP > 2 MoM, n =27). Screen positive women were further evaluated by ultrasound and 21 women were found to carry a neural tube defects positive pregnancy. Statistical analysis was done on SPSS software. Body weight of the women showed a significant positive correlation with serum triglycerides, plasma sugar and AFP MoM values. A significant difference was observed in serum cholesterol levels (p= 0.038), triglycerides (p=0.001) and plasma sugar levels (p=0.002) between normal women and those with neural tube defects positive pregnancy. The Odds ratio for neural tube defects risk in dyslipidemic cases was 24.23 (CI 4.73 - 148.60) with a relative risk of 12.12. Dyslipidemia especially hypertriglyceridemia was found to be significantly associated with fetal neural tube defects.

Survey of prenatal screening policies in Europe for structural malformations and chromosome anomalies, and their impact on detection and termination rates for neural tube defects and Down's syndrome

Objective

To ‘map’ the current (2004) state of prenatal screening in Europe.

Design

(i) Survey of country policies and (ii) analysis of data from EUROCAT (European Surveillance of Congenital Anomalies) population-based congenital anomaly registers.

Setting

Europe.

Population

Survey of prenatal screening policies in 18 countries and 1.13 million births in 12 countries in 2002–04.

Methods

(i) Questionnaire on national screening policies and termination of pregnancy for fetal anomaly (TOPFA) laws in 2004. (ii) Analysis of data on prenatal detection and termination for Down's syndrome and neural tube defects (NTDs) using the EUROCAT database.

Main outcome measures

Existence of national prenatal screening policies, legal gestation limit for TOPFA, prenatal detection and termination rates for Down's syndrome and NTD.

Results

Ten of the 18 countries had a national country-wide policy for Down's syndrome screening and 14/18 for structural anomaly scanning. Sixty-eight percent of Down's syndrome cases (range 0–95%) were detected prenatally, of which 88% resulted in termination of pregnancy. Eighty-eight percent (range 25–94%) of cases of NTD were prenatally detected, of which 88% resulted in termination. Countries with a first-trimester screening policy had the highest proportion of prenatally diagnosed Down's syndrome cases. Countries with no official national Down's syndrome screening or structural anomaly scan policy had the lowest proportion of prenatally diagnosed Down's syndrome and NTD cases. Six of the 18 countries had a legal gestational age limit for TOPFA, and in two countries, termination of pregnancy was illegal at any gestation.

Conclusions

There are large differences in screening policies between countries in Europe. These, as well as organisational and cultural factors, are associated with wide country variation in prenatal detection rates for Down's syndrome and NTD.

Please cite this paper as: Boyd P, DeVigan C, Khoshnood B, Loane M, Garne E, Dolk H, and the EUROCAT working group. Survey of prenatal screening policies in Europe for structural malformations and chromosome anomalies, and their impact on detection and termination rates for neural tube defects and Down's syndrome. BJOG 2008;115:689–696.

Effects of residential distance to hospitals with neonatal surgery care on prenatal management and outcome of pregnancies with severe fetal malformations

OBJECTIVES

To examine the effect of maternal origin and distance between maternal residence and the nearest maternity ward with a neonatal surgical center in the same hospital, on prenatal diagnosis, elective termination of pregnancy, delivery in an adequate place and neonatal mortality for pregnancies with severe malformations requiring neonatal surgery, and to examine the effect of the place of delivery on neonatal mortality.

METHODS

This was a retrospective study, through the France Central-East malformation registry, of 706 fetuses with omphalocele (n = 123), gastroschisis (n = 99), diaphragmatic hernia (n = 222), or spina bifida (n = 262), but without chromosomal anomalies. Maternal origin was classified as Western European and non-Western European. Adequate place for delivery was defined as birth in a Level-III maternity ward with a neonatal surgical center in the same hospital.

RESULTS

The prenatal diagnosis rate was 67.7% in 1990-1995 and 80.2% in 1996-2001 (odds ratio (OR), 2.07 (95% CI, 1.24-3.45)). On multivariate analysis, the rate was significantly lower for women living 11-50 km (adjusted OR, 0.49 (95% CI, 0.25-0.94)), or > 50 km (adjusted OR, 0.39 (0.20-0.74)) from the closest adequate place of delivery, compared with those living < 11 km from it, but there was no difference for maternal origin. Non-Western European women had fewer elective terminations of pregnancy (adjusted OR, 0.34 (95% CI, 0.14-0.81)) and fewer deliveries in an adequate place (adjusted OR, 0.40 (95% CI, 0.18-0.89)). Neonatal mortality was lower in the case of delivery in an adequate place (adjusted OR, 0.22 (95% CI, 0.07-0.72)) and was not associated with maternal origin and distance from nearest maternity ward with a neonatal surgical center.

CONCLUSION

Rate of prenatal diagnosis decreases with increasing distance between parental residence and referral center. Non-Western European women are diagnosed prenatally as often as are Western Europeans, but terminate their pregnancy less often, perhaps for cultural reasons. Non-Western European women with malformed fetuses deliver in adequate centers less often, probably because of the way the perinatal care system is run.

Prenatal diagnosis of open and closed spina bifida

OBJECTIVE

To identify criteria useful for differentiating closed from open spina bifida antenatally.

PATIENTS AND METHODS

A retrospective study of cases of spina bifida diagnosed in a referral center between 1997 and 2004.

RESULTS

Of 66 cases of fetal spina bifida diagnosed at a median gestational age of 21 (range, 16-34) weeks, detailed follow-up was available for 57. Of these, open defects were found in 53 (93.0%) and closed defects in four (7.0%). Closed spina bifida was associated in two cases with a posterior cystic mass with thick walls and a complex appearance, while in two cases the spinal lesion could not be clearly differentiated from an open defect, particularly at mid-gestation. Open spina bifida was always associated with typical alterations of cranial anatomy, including the so-called 'banana' and 'lemon' signs, while in closed spina bifida the cranium was unremarkable. When the data were available, levels of amniotic fluid alpha-fetoprotein were always abnormally elevated with open spina bifida and within normal limits with closed forms.

CONCLUSION

In this study 7% of cases of spina bifida diagnosed in utero were closed. The differentiation between open and closed forms is best shown by the sonographic demonstration of abnormal or normal cranial anatomy.

The prenatal ultrasonographic detection of myelomeningocele in patients referred to Children's Hospital Medical Center: a cross sectional study

BACKGROUND

To find out about the prenatal diagnosis rate of myelomeningocele (MMC) by ultrasound scan in patients referred to the Children's Hospital Medical Center in Tehran, Iran from July 2004 to July 2005.

METHODS

We included 140 children born with MMC and who were referred for management, surgery and treatment of complications associated with it. The ultrasound reports were examined. Data on sex, age, location of MMC, time of prenatal ultrasound and the trimester in which the diagnosis was made along with the results of the diagnosis (MMC, hydrocephalus, or both), were collected.

RESULTS

Among the studied patients, 136 (97.1%) cases had prenatal ultrasound, amongst those, 58 (42.6%) sonographic evaluations were diagnostic for hydrocephalus and/or MMC. The prenatal ultrasound was positive for MMC in 16 (11.8%), hydrocephalus in 25 (18.4%) and both MMC and hydrocephalus in 17 (12.5%) cases. Among all cases with prenatal diagnosis of MMC, 3.4% were detected in the first, 31% in the second and 65.5% in the third trimester. Thoracic/thoracolumbar lesions were found prenatally in 40% of cases, which is significantly higher than the detection rate of other locations including cervical/cervicothoracic and lumbar/lumbosacral/sacral regions diagnosed only in 0% and 21% of cases respectively.

CONCLUSION

There is a large difference between the detection rate of our population (24.3%) compared to others (68%). Pregnant women should have an ultrasound at 20-22 week for detection of congenital anomalies including MMC.

Antenatal ultrasound and magnetic resonance imaging in localizing the level of lesion in spina bifida and correlation with postnatal outcome

OBJECTIVE

To compare prenatal ultrasonography and magnetic resonance imaging (MRI) in the diagnosis of spina bifida with postnatal MRI/surgical findings and to study the postnatal outcome in relation to the level of lesion and head signs on antenatal imaging.

METHODS

A retrospective study of babies referred to a tertiary neurosurgical unit with a diagnosis of spina bifida in the years 2000-2002 was performed. The levels of lesions and head signs diagnosed using antenatal ultrasonography and MRI were compared with postnatal MRI and operative findings. The levels of lesions and head signs diagnosed pre- and postnatally were used to study the correlation with neurological outcome at a mean follow-up period of 12 months.

RESULTS

Twelve antenatally diagnosed and five postnatally diagnosed cases of spina bifida were seen. The level of lesion as identified by antenatal ultrasound correlated with that observed postnatally in 8/12 cases and the antenatal ultrasound diagnosis of ventriculomegaly was confirmed postnatally in all cases. The level of lesion as identified by antenatal MRI correlated with that observed postnatally in 4/8 cases (50%) and the antenatal MRI diagnosis of ventriculomegaly was confirmed postnatally in 5/8 (63%) cases. 12/17 babies were found to have residuals in the immediate postnatal urodynamic studies, of which 83% (n = 10) required intermittent catheterization of the bladder at 12 months of age. Low spinal lesions were associated with increased bladder morbidity when compared to high spinal lesions (8/10 vs. 4/7, P < 0.05) (odds ratio (OR) = 10.0; 95% CI, 1.05-95.01). The level of spinal lesion and the presence of ventriculomegaly did not have any statistically significant correlation with motor functions, morbidity and developmental milestones.

CONCLUSIONS

Antenatal ultrasonography is a good tool in the diagnosis of spina bifida. We could not demonstrate any advantage of antenatal MRI over ultrasonography. There is better correlation of ultrasonography than MRI with postnatal MRI/operative findings in terms of level of lesion and head signs. Low spinal lesions appear to be associated with increased bladder morbidity.

Experiences of prenatal diagnosis of spina bifida or hydrocephalus in parents who decide to continue with their pregnancy

The current study aimed to gain an understanding of the perspectives of those parents provided with a prenatal diagnosis of spina bifida or hydrocephalus and who decided to continue with their pregnancy. Qualitative interviews were conducted with 15 parents who learned of their unborn child's spina bifida and/or hydrocephalus in the prenatal period. The interviewer asked parents about their experiences of receiving a prenatal diagnosis and their experience of coping throughout the remainder of the antenatal period. Parents' reactions and experiences fell into five domains: response to diagnosis, experience of medical systems, information gathering, decision-making regarding continuation of the pregnancy following diagnosis and responses of significant others. Each of these domains is explicated. The findings derived from the current study have implications for professionals who provide support to parents during the prenatal period. Future research needs to further explore the common and unique issues for parents living in both urban and rural areas.

Economic modelling of antenatal screening and ultrasound scanning programmes for identification of fetal abnormalities

OBJECTIVE

Within the framework of a health technology assessment and using an economic model, to determine the most clinically and cost effective policy of scanning and screening for fetal abnormalities in early pregnancy.

DESIGN

A discrete event simulation model of 50,000 singleton pregnancies.

SETTING

Maternity services in Scotland.

POPULATION

Women during the first 24 weeks of their pregnancy.

METHODS

The mathematical model was populated with data on uptake of screening, prevalence, detection and false positive rates for eight fetal abnormalities and with costs for ultrasound scanning and serum screening. Inclusion of abnormalities was based on the relative prevalence and clinical importance of conditions and the availability of data. Six strategies for the identification of abnormalities prenatally including combinations of first and second trimester ultrasound scanning and first and second trimester screening for chromosomal abnormalities were compared.

MAIN OUTCOME MEASURES

The number of abnormalities detected and missed, the number of iatrogenic losses resulting from invasive tests, the total cost of strategies and the cost per abnormality detected were compared between strategies.

RESULTS

First trimester screening for chromosomal abnormalities costs more than second trimester screening but results in fewer iatrogenic losses. Strategies which include a second trimester ultrasound scan result in more abnormalities being detected and have lower costs per anomaly detected.

CONCLUSIONS

The preferred strategy includes both first and second trimester ultrasound scans and a first trimester screening test for chromosomal abnormalities. It has been recommended that this policy is offered to all women in Scotland.

Prenatal diagnosis of severe structural congenital malformations in Europe

OBJECTIVES

To assess at a population-based level the frequency with which severe structural congenital malformations are detected prenatally in Europe and the gestational age at detection, and to describe regional variation in these indicators.

METHODS

In the period 1995-1999, data were obtained from 17 European population-based registries of congenital malformations (EUROCAT). Included were all live births, fetal deaths and terminations of pregnancy diagnosed with one or more of the following malformations: anencephalus, encephalocele, spina bifida, hydrocephalus, transposition of great arteries, hypoplastic left heart, limb reduction defect, bilateral renal agenesis, diaphragmatic hernia, omphalocele and gastroschisis.

RESULTS

The 17 registries reported 4366 cases diagnosed with the 11 severe structural malformations and of these 2300 were live births (53%), 181 were fetal deaths (4%) and 1863 were terminations of pregnancy (43%); in 22 cases pregnancy outcome was unknown. The overall prenatal detection rate was 64% (range, 25-88% across regions). The proportion of terminations of pregnancy varied between regions from 15% to 59% of all cases. Gestational age at discovery for prenatally diagnosed cases was less than 24 weeks for 68% (range, 36-88%) of cases. There was a significant relationship between high prenatal detection rate and early diagnosis (P < 0.0001). For individual malformations, the prenatal detection rate was highest for anencephalus (469/498, 94%) and lowest for transposition of the great arteries (89/324, 27%). Termination of pregnancy was performed in more than half of the prenatally diagnosed cases, except for those with transposition of the great arteries, diaphragmatic hernia and gastroschisis, in which 30-40% of the pregnancies with a prenatal diagnosis were terminated.

CONCLUSION

European countries currently vary widely in the provision and uptake of prenatal screening and its quality, as well as the "culture" in terms of decision to continue the pregnancy. This inevitably contributes to variation between countries in perinatal and infant mortality and in childhood prevalence and cost to health services of congenital anomalies.

Contribution of ultrasonographic examination to the prenatal detection of trisomy 21: experience from 19 European registers

The objective of this study was to evaluate the contribution of ultrasound scanning to the prenatal detection of trisomy 21 in a large unselected European population. Data from 19 congenital malformation registers in 11 European countries were included. The prenatal ultrasound screening programs in the countries ranged from no routine screening to three ultrasound investigations per patient. Routine serum screening was offered in four of the 11 countries and routine screening on the basis of maternal age amniocentesis in all. The results show that overall 53% of cases of trisomy 21 were detected prenatally with a range from 3% in Lithuania to 88% in Paris. Ninety-eight percent of women whose babies were diagnosed before 24 weeks gestation chose to terminate the pregnancy. Centres/countries that offer serum screening do not have a significantly higher detection rate of trisomy 21 when compared to those that offer maternal age amniocentesis and anomaly scanning only. Fifty percent of trisomy 21 cases were born to women aged 35 years or more. In conclusions, second trimester ultrasound plays an important role in the prenatal diagnosis of trisomy 21. Of those cases prenatally diagnosed, 64% of cases in women <35 years and 36% of those in women >or=35 years were detected because of an ultrasound finding. Ultrasound soft markers accounted for 84% of the scan diagnoses. There is evidence of increasing maternal age across Europe with 50% of cases of trisomy 21 born to women aged 35 years or more.

Uso da ultra-sonografia na triagem de disrafismos espinhais ocultos

O uso da ultra-sonografia para diagnóstico de lesões da coluna vertebral é difundido desde a década de oitenta. Suas aplicações envolvem: diagnóstico de lesões medulares traumáticas; uso intra-operatório em cirurgias do trauma e tumores medulares; uso pré-operatório e evolutivo em pacientes com disrafismos espinhais; diagnóstico pré-natal dos disrafismos; diagnóstico dos disrafismos espinhais ocultos ao nascimento. Pacientes com suspeita de disrafismo espinhal oculto (estigmas cutâneos em linha média ou história familiar de disrafismos) representaram a principal indicação do exame que foi realizado em 292 pacientes do Hospital das Clínicas da Universidade Federal de Minas Gerais. Alterações como lipomas do cone medular, medula baixa, filo terminal espesso, cistos da ponta do cone medular e seios dérmicos foram identificados com fidelidade à ultra-sonografia. A interpretação do exame não apresentou dificuldades técnicas. Sua realização é rápida, não é necessária sedação, apresenta baixo custo e idealmente deve ser realizado pelo próprio neurocirurgião devido ao grande número de informações possíveis durante o exame. O exame entretanto não substitui a ressonância magnética mas pode ser um bom método de triagem para os pacientes.

Genetic analysis of lethal congenital malformations causing perinatal mortality at Nizwa Hospital, Oman

An analysis of lethal congenital malformations (LCM) - which contributed to perinatal mortality at Nizwa Hospital, Oman - is presented for a 10-year period from January 1993 through December 2002. Single gene, chromosomal or multifactorial inheritance accounted for 86.1% of the cases. LCM-related perinatal deaths were higher in Omani, compared to those in non-Omani births (p < 0.001). This could possibly be attributed to high consanguinity, low female literacy and high fertility rates in the Omani population. Forty per cent of LCM-related perinatal deaths in the study had potential options for prevention. Integration of a community-based genetic service into the existing health-care delivery system is suggested.

Prenatal diagnosis of dysmorphic syndromes by routine fetal ultrasound examination across Europe

OBJECTIVES

Ultrasound scan in the mid-trimester of pregnancy is now a routine part of prenatal care in most European countries. The objective of this study was to evaluate the prenatal diagnosis of dysmorphic syndromes by fetal ultrasound examination.

METHODS

Data from 20 registries of congenital malformations in 12 European countries were included in the study.

RESULTS

There were 2454 cases with congenital heart diseases, 479 of which were recognized syndromes, including 375 chromosomal anomalies and 104 syndromes without chromosomal anomalies. Fifty-one of the 104 were detected prenatally (49.0%). One hundred and ninety-two of 1130 cases with renal anomalies were recognized syndromes, including 128 chromosomal anomalies and 64 syndromes without chromosomal anomalies; 162 of them (84.4%) were diagnosed prenatally, including 109 chromosomal anomalies and 53 non-chromosomal syndromes. Fifty-four of the 250 cases with limb defects were recognized syndromes, including 16 chromosomal syndromes and 38 syndromes without chromosomal anomalies; 21 of these 54 syndromes were diagnosed prenatally (38.9%), including 9 chromosomal syndromes. There were 243 cases of abdominal wall defects including 57 recognizable syndromes, 48 with omphalocele and 9 with gastroschisis; 48 were diagnosed prenatally (84.2%). Twenty-six of the 187 cases with diaphragmatic hernia had recognized syndromes, including 20 chromosomal aberrations and 6 syndromes without chromosomal anomalies. Twenty-two of them (84.6%) were detected prenatally. Sixty-four of 349 cases with intestinal anomalies were recognized syndromes; 24 were diagnosed prenatally (37.5%). There were 553 cases of cleft lip and palate (CL(P)) and 198 of cleft palate (CP) including 74 chromosomal anomalies and 73 recognized non-chromosomal syndromes. Prenatal diagnosis was made in 51 cases of CL(P) (53.7%) and 7 of CP (13.7%). Twenty-two of 188 anencephalic cases were syndromic and all were diagnosed prenatally. Of 290 cases with spina bifida, 18 were recognized syndromes, and of them 17 were diagnosed prenatally. All 11 syndromic encephaloceles were diagnosed prenatally.

CONCLUSIONS

Around 50% of the recognized syndromes which are associated with major congenital anomalies (cardiac, renal, intestinal, limb defects, abdominal wall defects and oral clefts) can be detected prenatally by the anomaly scan. However the detection rate varies with the type of syndrome and with the different countries' policies of prenatal screening.

Survival of infants diagnosed with encephalocele in Atlanta, 1979-98

This study aimed to evaluate the survival of a cohort of liveborn infants diagnosed with encephalocele during a 20-year period and the variation of such survival by selected demographic and clinical characteristics. We reviewed data from the Metropolitan Atlanta Congenital Defects Program (MACDP) to ascertain all live births diagnosed with encephalocele (n = 83) from 1979 to 1998. Of these, 66 (79%) had isolated defects. Among 70 liveborn infants with site of the defect specified, 50 were classified as having posterior and 20 with anterior defects. To identify their vital status, we used data from MACDP hospital records and vital records from the State of Georgia supplemented by linking registry data with the National Death Index from 1979 to 1999. Among children with encephalocele, 76.0% of the deaths (19/25) occurred during the first day of life. The survival probability to 1 year of age was 70.8%[95% confidence intervals (CI) 60.9, 80.7] and to 20 years of age was 67.3%[95% CI 55.7, 78.8]. In multivariable analysis, factors associated with increased mortality were low birthweight (<2500 g) [relative risk (RR) 5.18; 95% CI 2.13, 12.63], presence of multiple defects (RR 2.82; 95% CI 1.19, 6.69) and black race (RR 2.36; 95% CI 0.95, 5.85). Overall survival for infants with multiple defects (41.2%) was significantly poorer than survival among those with isolated defects (74.3%). A 70% decrease in risk of mortality was observed among infants born with encephalocele during 1989-98 compared with those born during 1979-88, but this decrease was evident only among cases with low birthweight (RR 0.29; 95% CI 0.01, 0.90). This study highlights the prognostic importance of multiple defects and low birthweight for infants with encephalocele and identifies a statistically significant difference in survival by race. This information is useful for clinicians and families who must plan for the long-term care of affected children.

Diagnosis and prevention of neural tube defects

PURPOSE OF REVIEW

Neural tube defects, including anencephaly, meningomyelocele and encephalocele, are among the most common birth defects that result in severe mortality and morbidity. Neural tube defects occur with an incidence of 1-5 per 1000 births, showing marked geographic, ethnic and temporal variations. Although clear evidence exists on preventability of a large proportion of neural tube defects by periconceptional folic acid intake, only a low percentage of women are following the recommendations.

RECENT FINDINGS

In the past few decades diagnostic modalities have undergone a change from blood screening tests, such as alpha-fetoprotein, to imaging methods. Ultrasound has become the standard tool for early diagnosis, whereas fetal magnetic resonance imaging has gained importance in evaluating distinct coexisting anomalies of the central nervous system. Since the United States authorized the addition of folic acid to grain products in 1996, many other countries are considering folic acid fortification of their grain products, or have started fortification. Hitherto there is no consensus either to the duration of supplementation or to the best dose.

SUMMARY

Ultrasound and magnetic resonance imaging offer the possibility of early and accurate diagnosis of neural tube defects, and have therefore improved medical counseling and parents' decision making. Food fortification is the most practical way of ensuring sufficient folate supplementation and is warranted during the periconceptional period.

Impact of prenatal diagnosis on livebirth prevalence of children with congenital anomalies

The objectives of this study were to describe the impact of prenatal diagnosis on the birth prevalence of congenital anomalies over 21 years (1979-1999) in a well defined population in northeastern France (13,500 births per year). The material for this study came from the analysis of data from multiple sources on births and terminations of pregnancy after prenatal diagnosis of congenital anomalies in 279,642 consecutive pregnancies of known outcome. The study period was divided into three subgroups 1979-1988, 1989-1993 and 1994-1999. Between 1979-1988, 1989-1993 and 1994-1999, prenatal detection of congenital anomalies increased, respectively, from 12.0% to 25.5% and to 31.7%. Termination of pregnancy (TOP) increased in the same proportions during the three time periods. However, the increase of TOP was much higher for chromosomal anomalies than for nonchromosomal congenital anomalies. The birth prevalence of Down's syndrome fell by 80% from 1979-1988 to 1994-1999. Sensitivity of prenatal detection of congenital anomalies and TOPs were lower for isolated cases (only one malformation present in the fetus) than for multiple malformations in the same fetus. Sensitivity varied with the type of malformations: it was high for neural tube defect (79.7%) and urinary anomalies (50.7%) and low for congenital heart defects (16.4%). In conclusion, the introduction of routine prenatal diagnosis has resulted in a significant fall in the birth prevalence of children with congenital anomalies. However, this fall varied with the types of congenital anomalies.

Congenital diaphragmatic hernia: evaluation of prenatal diagnosis in 20 European regions

OBJECTIVE

To evaluate prenatal diagnosis of congenital diaphragmatic hernia by ultrasound in well-defined European populations.

DESIGN

Data from 20 registries of congenital malformations in 12 European countries were included. The prenatal ultrasound screening programs in the countries ranged from no routine screening to three ultrasound investigations per patient being routinely performed.

RESULTS

There were 187 cases with congenital diaphragmatic hernia, with an overall prenatal detection rate of 59% (110/187). There was considerable variation in prenatal detection rate between regions. There was a significant difference in the detection rate of isolated congenital diaphragmatic hernia (59/116, 51%) compared with congenital diaphragmatic hernia associated with multiple malformations, karyotype anomalies or syndromes (51/71, 72%) (P = 0.01). Termination of pregnancy was performed in 39 cases (21%) of which 14 cases were isolated congenital diaphragmatic hernia. Mean gestational age at discovery was 24.2 weeks (range, 11-38 weeks).

CONCLUSIONS

The overall prenatal detection rate of congenital diaphragmatic hernia is high (59%) but varies significantly between European regions. The gestational age at discovery was greater than 24 weeks in half of the prenatally diagnosed cases.