Fetal echogenic bowel: parameters to be considered in differential diagnosis

Fetal echogenic bowel: Is there a national consensus on identification and reporting?

Introduction

Saving Babies' Lives Care Bundle Version 2 highlights the importance of correct identification and reporting of echogenic bowel to improve maternal and newborn outcomes. Yet there is no national consensus to guide sonographers in identifying and reporting fetal echogenic bowel. This two-phase study aims to develop a national consensus to guide sonographers on the identification, classification and reporting of fetal echogenic bowel during the Fetal Anomaly Screening Programme (FASP) second trimester anomaly scan. Phase 1 results are presented capturing the national current practice of sonographers in its identification.

Methods

An online questionnaire survey was deployed to capture numerical and free text data. Data analysis was by descriptive statistics. Participants were recruited via social media and through professional networks and organisations.

Results

A total of 95 participants completed the questionnaire during an 11-week period. Common practice across England included sonographers using a subjective method for identifying fetal echogenic bowel and making comparisons to fetal bone. However, there was wide variance in the fetal bone used and the transducer frequency typically used to assess bowel echogenicity. Confirmation of echogenic bowel was made at the 20-week scan in 58% of cases, 32% following fetal medicine department review with the remaining 10% unsure when confirmation occurred.

Conclusion

While there is common practice in identifying and report echogenic fetal bowel in some areas, there remains disparity within sonographer practice in England's national screening service. This study allowed baseline data to be collated, providing the first steps towards development of guidance for sonographers in identifying and reporting this appearance.

In utero ultrasound diagnosis of bilateral cataract and hydrops in a mule pregnancy: Case report

Once diagnosed pregnant with ultrasound at an early stage of gestation, mares are usually not examined before foaling. The objective of this case report was to highlight the importance of transrectal ultrasound screening examination and to report a unique case of fetal congenital cataracts associated with other feto-placental abnormalities in a mule pregnancy, its in utero ultrasound diagnosis and outcome. A 17-year-old Thoroughbred research mare carrying a mule fetus was examined by transrectal ultrasonography at 186 days of gestation for a routine pregnancy examination. Ultrasonography allowed in utero diagnosis of fetal congenital cataracts, hyperechogenic bowels, intrauterine growth restriction (IUGR), hydramnios and placental abnormalities. The mare was monitored bi-monthly to observe the progress of the pregnancy. At 258 days of gestation, the abnormal chorioallantois detached at the cervical star and at 272 days, fetal asystole was diagnosed. Abortion was induced and the fetus was delivered uneventfully. Post-mortem gross and histologic findings confirmed the prenatal ultrasonographic diagnosis. This case highlights the diagnostic value of a complete fetal ultrasound examination to detect equine fetal abnormalities.

Hyperechogenic fetal bowel: Current evidence-based prenatal diagnosis and management

Echogenic fetal bowel (EB) is a prenatal ultrasound finding (0.2%-1.4% of all pregnancies) defined as bowel of similar or greater echogenicity than surrounding bone. In fact, the ultrasound assessment is strongly subjective with inter-observer variability. The pathophysiology depends on the underlying condition, apparently related with meconium stasis and hypercellularity. It is often an isolated finding, with possible association with other structural anomalies. About the origin, it was observed in fetuses with cystic fibrosis, congenital infections, thalassemia, intraamniotic bleeding, fetal growth restriction. Fetuses with EB are at increased risk of adverse perinatal outcome, such as intrauterine growth restriction, placental dysfunction and perinatal death, highlighting the need for a thorough antenatal management and post-natal follow-up. It seems to be associated with a plenty of conditions, such as a poor fetal outcome, fetal growth restriction and placental dysfunction. Therefore management requires a multidisciplinary approach with different specialties' involvement and the prognosis is influenced by the underlying pathophysiology. In this complex scenario, the present review aims to define the clinical pathway which should be offered to pregnant women in case of finding of fetal EB ultrasound marker, to rule out any suspected pathological cause.

Isolated fetal echogenic bowel and iron-rich mineral water supplement: a case series and review of the literature

Natural iron-rich mineral water (IRMW) is a supplement with a higher iron bioavailability than oral iron supplement tablets. Five (4%) of 116 women who consumed IRMW starting from 16 weeks of gestation were diagnosed as having isolated foetal echogenic bowel at a single community maternity clinic between 2012 and 2015. The workup of all the women was otherwise negative. Four women taking IRMW were re-checked after discontinuation of the supplement and had a normal-appearing foetal bowel. Our observations suggest that isolated echogenic bowel may be related to the consumption of IRMW, possibly due to the high absorption of iron, leading to the coating of the internal wall of the foetal bowel and subsequent appearance of an echogenic bowel. Although this finding appears free of harmful ramifications, its possible sonographic effects on the appearance of the foetal bowel should be considered in light of the increasing popularity of IRMW use.IMPACT STATEMENTWhat is already known on this subject? IRMW is a highly absorbed iron supplement. The differential diagnosis for foetal echogenic bowel is broad and requires thorough investigation. Iron is secreted through the maternal blood to the amniotic fluid, which is swallowed by the foetus, reaching its bowel.What do the results of this study add? IRMW consumption is a possible aetiology of an isolated foetal echogenic bowel in the second half of pregnancy, conveying no risk of foetal morbidity or mortality.What are the implications of these findings for clinical practice and/or further research? In light of the increasing popularity of IRMW, we believe that it is important to increase the level of awareness of the possible effects of its intake on the sonographic appearance of the foetal bowel.

Society for Maternal-Fetal Medicine Consult Series #57: Evaluation and management of isolated soft ultrasound markers for aneuploidy in the second trimester: (Replaces Consults #10, Single umbilical artery, October 2010; #16, Isolated echogenic bowel diagnosed on second-trimester ultrasound, August 2011; #17, Evaluation and management of isolated renal pelviectasis on second-trimester ultrasound, December 2011; #25, Isolated fetal choroid plexus cysts, April 2013; #27, Isolated echogenic intracardiac focus, August 2013)

Soft markers were originally introduced to prenatal ultrasonography to improve the detection of trisomy 21 over that achievable with age-based and serum screening strategies. As prenatal genetic screening strategies have greatly evolved in the last 2 decades, the relative importance of soft markers has shifted. The purpose of this document is to discuss the recommended evaluation and management of isolated soft markers in the context of current maternal serum screening and cell-free DNA screening options. In this document, "isolated" is used to describe a soft marker that has been identified in the absence of any fetal structural anomaly, growth restriction, or additional soft marker following a detailed obstetrical ultrasound examination. In this document, "serum screening methods" refers to all maternal screening strategies, including first-trimester screen, integrated screen, sequential screen, contingent screen, or quad screen. The Society for Maternal-Fetal Medicine recommends the following approach to the evaluation and management of isolated soft markers: (1) we do not recommend diagnostic testing for aneuploidy solely for the evaluation of an isolated soft marker following a negative serum or cell-free DNA screening result (GRADE 1B); (2) for pregnant people with no previous aneuploidy screening and isolated echogenic intracardiac focus, echogenic bowel, urinary tract dilation, or shortened humerus, femur, or both, we recommend counseling to estimate the probability of trisomy 21 and a discussion of options for noninvasive aneuploidy screening with cell-free DNA or quad screen if cell-free DNA is unavailable or cost-prohibitive (GRADE 1B); (3) for pregnant people with no previous aneuploidy screening and isolated thickened nuchal fold or isolated absent or hypoplastic nasal bone, we recommend counseling to estimate the probability of trisomy 21 and a discussion of options for noninvasive aneuploidy screening through cell-free DNA or quad screen if cell-free DNA is unavailable or cost-prohibitive or diagnostic testing via amniocentesis, depending on clinical circumstances and patient preference (GRADE 1B); (4) for pregnant people with no previous aneuploidy screening and isolated choroid plexus cysts, we recommend counseling to estimate the probability of trisomy 18 and a discussion of options for noninvasive aneuploidy screening with cell-free DNA or quad screen if cell-free DNA is unavailable or cost-prohibitive (GRADE 1C); (5) for pregnant people with negative serum or cell-free DNA screening results and an isolated echogenic intracardiac focus, we recommend no further evaluation as this finding is a normal variant of no clinical importance with no indication for fetal echocardiography, follow-up ultrasound imaging, or postnatal evaluation (GRADE 1B); (6) for pregnant people with negative serum or cell-free DNA screening results and isolated fetal echogenic bowel, urinary tract dilation, or shortened humerus, femur, or both, we recommend no further aneuploidy evaluation (GRADE 1B); (7) for pregnant people with negative serum screening results and isolated thickened nuchal fold or absent or hypoplastic nasal bone, we recommend counseling to estimate the probability of trisomy 21 and discussion of options for no further aneuploidy evaluation, noninvasive aneuploidy screening through cell-free DNA, or diagnostic testing via amniocentesis, depending on clinical circumstances and patient preference (GRADE 1B); (8) for pregnant people with negative cell-free DNA screening results and isolated thickened nuchal fold or absent or hypoplastic nasal bone, we recommend no further aneuploidy evaluation (GRADE 1B); (9) for pregnant people with negative serum or cell-free DNA screening results and isolated choroid plexus cysts, we recommend no further aneuploidy evaluation, as this finding is a normal variant of no clinical importance with no indication for follow-up ultrasound imaging or postnatal evaluation (GRADE 1C); (10) for fetuses with isolated echogenic bowel, we recommend an evaluation for cystic fibrosis and fetal cytomegalovirus infection and a third-trimester ultrasound examination for reassessment and evaluation of growth (GRADE 1C); (11) for fetuses with an isolated single umbilical artery, we recommend no additional evaluation for aneuploidy, regardless of whether results of previous aneuploidy screening were low risk or testing was declined. We recommend a third-trimester ultrasound examination to evaluate growth and consideration of weekly antenatal fetal surveillance beginning at 36 0/7 weeks of gestation (GRADE 1C); (12) for fetuses with isolated urinary tract dilation A1, we recommend an ultrasound examination at ≥32 weeks of gestation to determine if postnatal pediatric urology or nephrology follow-up is needed. For fetuses with urinary tract dilation A2-3, we recommend an individualized follow-up ultrasound assessment with planned postnatal follow-up (GRADE 1C); (13) for fetuses with isolated shortened humerus, femur, or both, we recommend a third-trimester ultrasound examination for reassessment and evaluation of growth (GRADE 1C).

Performance of Chromosomal Microarray Analysis for Detection of Copy Number Variations in Fetal Echogenic Bowel

BACKGROUND

Fetal echogenic bowel (FEB) is associated with an increased risk of poor pregnant outcomes; however, karyotyping fails to detect copy number variations (CNVs) in FEB. This study aimed to evaluate the performance of chromosomal microarray analysis (CMA) for detection of FEB.

METHODS

The medical records of 147 pregnant women with FEB recruited during December 2015 to December 2018 were retrospectively reviewed, and prenatal samples were collected for karyotyping and CMA. The detection of chromosomal abnormality was compared between karyotyping and CMA.

RESULTS

Karyotyping identified eight cases with abnormal karyotypes (5.44% prevalence), including four fetuses with pathogenic aneuploidy, three with chromosome polymorphism and one with balanced chromosome translocation. CMA identified 13 abnormal CNVs (8.84% prevalence), including 4 fetuses with pathogenic aneuploidy as detected by karyotyping and 9 additional CNVs with normal karyotypes; however, CMA failed to detect chromosome polymorphism and balanced chromosome translocation. In fetuses with isolated FEB, no cases presented pathogenic findings and CMA detected two cases with variants of uncertain significance (VOUS). In cases presenting FEB along with other ultrasound abnormalities, CMA detected three cases with pathogenic CNVs and four cases with VOUS in addition to four cases with aneuploidy. There was no significant difference in the detection of abnormal CNVs between the fetuses with echogenic bowel alone and along with other ultrasound abnormalities (10% vs 8.67%, P > 0.05). Except 9 fetuses lost to the follow-up, the other 138 fetuses with echogenic bowel were successfully followed up. Pregnancy was terminated in 5 fetuses with chromosomal abnormality, 2 with pathogenic CNVs and 1 with VOUS, and other 16 with normal karyotypes and CMA findings but showing ultrasound abnormalities or multiple malformations.

CONCLUSION

Isolated FEB is associated with a good prognosis, and a satisfactory pregnant outcome is expected for fetuses with echogenic bowel that are negative for chromosomal anomalies and other severe structure abnormalities. CMA shows an important value in the genetic diagnosis of FEB. As a supplement to karyotyping, CMA may improve the accuracy of prenatal diagnosis of fetal intestinal malformations in pregnant women with FEB.

Outcome of fetal echogenic bowel: A systematic review and meta-analysis

The main aim of this systematic review was to explore the outcome of fetuses with isolated echogenic bowel (EB) on antenatal ultrasound. Inclusion criteria were singleton pregnancies with isolated EB no associated major structural anomalies at the time of diagnosis. The outcomes observed were: chromosomal anomalies, cystic fibrosis (CF), associated structural anomalies detected only at follow-up scans and at birth, regression during pregnancy, congenital infections, intra-uterine (IUD), neonatal (NND) and perinatal (PND) death. Twenty-five studies (12 971 fetuses) were included. Chromosomal anomalies occurred in 3.3% of the fetuses, mainly Trisomy 21 and aneuploidies involving the sex chromosomes. Cystic fibrosis occurred in 2.2%. Congenital infections affected 2.2%, mainly congenital Cytomegalovirus (CMV) infection. The majority of fetuses with EB experienced regression or disappearance of the EB at follow-up scans. Associated anomalies were detected at a follow-up scan in 1.8%. Associated anomalies were detected at birth and missed at ultrasound in 2.1% of cases. IUD occurred in 3.2% of cases while the corresponding figures for NND and PND were 0.4% and 3.1%. Fetuses with EB are at increased risk of adverse perinatal outcome, highlighting the need for a thorough antenatal management and postnatal follow-up. Assessment during pregnancy and after birth should be performed in order to look for signs of fetal aneuploidy, congenital infections and associated structural anomalies.

Ultrasound features of fetal toxoplasmosis: A contemporary multicenter survey in 88 fetuses

OBJECTIVE

To describe the lesions detected by prenatal ultrasound examination in congenital toxoplasmosis (CT).

METHODS

We retrospectively analyzed all cases of fetal infection with Toxoplasma gondii with ultrasound anomalies described by fetal medicine experts in 2009 to 2019 in 30 French centers.

RESULTS

Eighty-eight cases of CT were included. Forty-five (51.1%) had one or more cerebral signs only, 35 (39.8%) had cerebral plus extracerebral signs and 8 (9.1%) had extracerebral signs only. The main cerebral signs were intracranial hyperechogenic nodular foci (n = 60) of which 20 were isolated, ventriculomegalies (n = 44) which generally increased during follow-up, and periventricular abscesses (n = 12). The main extracerebral signs were hepatomegaly and/or splenomegaly (n = 14), small for gestational age (n = 14), ascites (n = 14, including 2 with hydrops), and hyperechogenic bowel (n = 11). Maternal infection occurred mostly in the first or second trimester (81 cases), periconceptionally in one and in the third trimester in six cases. The first ultrasound signs were detected after a median of 7 weeks (range: 1.4; 24.0) following maternal toxoplasmosis seroconversion.

CONCLUSION

While no sign was specific of CT, there were typical associations of cerebral signs with or without extracerebral signs. Detailed ultrasound examination could improve prognostic evaluation, as well as diagnosis of CT in settings lacking serological screening.

The MRI spectrum of congenital cytomegalovirus infection

Human cytomegalovirus (CMV) is an ubiquitous pathogen, with a high worldwide seroprevalence. When acquired in the prenatal period, congenital CMV (cCMV) is a major cause of neurodevelopmental sequelae and hearing loss. cCMV remains an underdiagnosed condition, with no systematic screening implemented in pregnancy or in the postnatal period. Therefore, imaging takes a prominent role in prenatal diagnosis of cCMV. With the prospect of new viable therapies, accurate and timely diagnosis becomes paramount, as well as identification of fetuses at risk for neurodevelopmental sequelae. Fetal magnetic resonance imaging (MRI) provides a complementary method to ultrasound (US) in fetal brain and body imaging. Anterior temporal lobe lesions are the most specific finding, and MRI is superior to US in their detection. Other findings such as ventriculomegaly, cortical malformations and calcifications, as well as hepatosplenomegaly, liver signal changes and abnormal effusions are unspecific. However, when seen in combination these should raise the suspicion of fetal infection, highlighting the need for a full fetal assessment. Still, some fetuses deemed normal on prenatal imaging are symptomatic at birth or develop delayed cCMV-associated symptoms, leaving room for improvement of diagnostic tools. Advanced MR sequences may help in this field and in determining prognosis, but further studies are needed.

Isolated fetal echogenic bowel in a retrospective cohort: The role of infection screening

OBJECTIVE

Fetal echogenic bowel (FEB) is an ultrasonographic marker of fetal infection. We aimed to determine the utility of infection screening when FEB is isolated.

STUDY DESIGN

Retrospective observational study of isolated FEB cases between 2006-2014. Infection screening included toxoplasmosis, rubella, syphilis, cytomegalovirus (CMV), herpes simplex virus and parvovirus B19. Fetal karyotyping, screening for cystic fibrosis (CF) and follow-up scans were also offered, according to international standards. Incidence of infection and 95% confidence interval (CI) were calculated.

RESULTS

148 patients with 154 fetuses were included. 4.7% of mothers developed acute infection: four patients developed CMV infection (2.7%, 95% CI 1.1-6.9%), in two fetuses infection was confirmed with amniocentesis and pregnancies were terminated; Parvovirus B19 infection was detected in 2 patients (1.4%, 95% CI 0.4-5.0) and confirmed in one fetus, which developed anemia; there was one toxoplasmosis maternal infection (0.7%, 95% CI 0.1-3.8%) treated with spyramicin, whose fetus was not infected. Percentage of chromosomal/genetic abnormalities was 3.2%, CF 1.3%, intra-amniotic bleeding 1.3%, FGR 34% and other ultrasonographic abnormalities at follow-up scans 18%.

CONCLUSIONS

The association between isolated FEB and fetal infection is uncommon (1.9% in our population). CMV maternal infection screening is supported by our findings, whereas screening for other infections needs to be further investigated.

Gut microbiota, the immune system, and diet influence the neonatal gut-brain axis

The conceptual framework for a gut-brain axis has existed for decades. The Human Microbiome Project is responsible for establishing intestinal dysbiosis as a mediator of inflammatory bowel disease, obesity, and neurodevelopmental disorders in adults. Recent advances in metagenomics implicate gut microbiota and diet as key modulators of the bidirectional signaling pathways between the gut and brain that underlie neurodevelopmental and psychiatric disorders in adults. Evidence linking intestinal dysbiosis to neurodevelopmental disease outcomes in preterm infants is emerging. Recent clinical studies show that intestinal dysbiosis precedes late-onset neonatal sepsis and necrotizing enterocolitis in intensive care nurseries. Moreover, strong epidemiologic evidence links late-onset neonatal sepsis and necrotizing enterocolitis in long-term psychomotor disabilities of very-low-birth-weight infants. The notion of the gut-brain axis thereby supports that intestinal microbiota can indirectly harm the brain of preterm infants. In this review, we highlight the anatomy and physiology of the gut-brain axis and describe transmission of stress signals caused by immune-microbial dysfunction in the gut. These messengers initiate neurologic disease in preterm infants. Understanding neural and humoral signaling through the gut-brain axis will offer insight into therapeutic and dietary approaches that may improve the outcomes of very-low-birth-weight infants.

The effect of associated structural malformations in the prediction of chromosomal abnormality risk of fetuses with echogenic bowel

OBJECTIVE

Our aim is to determine the frequency of chromosomal abnormalities and also to identify the role of structural malformations on the chromosomal abnormality risk among fetuses with echogenic bowel.

METHODS

Over a 6-year period fetuses with echogenic bowel (FEB) were retrospectively evaluated. The pregnancies with intra-amniotic bleeding history, congenital infection, cystic fibrosis and intrauterine growth retardation were excluded from the study. Types and frequency of sonographically detected fetal malformations were identified. Chromosomal abnormality incidences according to association with soft markers and major fetal abnormalities were compared.

RESULTS

Of the 281 fetuses with echogenic bowel, 105 (37.37%) were isolated, 78 (27.76%) were associated with soft markers and 98 (34.87%) were associated with major abnormalities. There were 30 (10.7%) fetuses with abnormal karyotypes. The chromosomal abnormality rate of the groups of isolated FEB, FEB + soft markers and FEB + major abnormalities were 6.7%, 7.7% and 17.4%, respectively.

CONCLUSIONS

Chromosomal abnormality risk in fetuses with echogenic bowel should be evaluated according to additional sonographic findings. Association of structural malformations increases the chromosomal abnormality risk, although this risk is not significant with the presence of soft markers alone.

[Neonatal outcome of fetal hyperechogenic bowel]

OBJECTIVE

Echogenic bowel (EB) represents 1 % of pregnancy and is a risk factor of fetal pathology (infection, cystic fibrosis, aneuploidy). The aim of our study was to determine the fetuses' outcomes with isolated EB.

PATIENTS AND METHODS

This is a retrospective study of all patients who presented singleton gestations with a fetal isolated echogenic bowel between 2004 and 2011 in two prenatal diagnosis centers. Search of aneuploidy, infection and cystic fibrosis was systematically proposed as well as an ultrasound monitoring.

RESULTS

On 109 fetus addressed for isolate echogenic bowel five had other signs associated and 74 had a real isolated echogenic bowel (without dilatation, calcification, intrauterine growth restriction). In 30 cases, the EB was not found. Eighty-five percent of the patients had in the first trimester a screening for trisomy 21. None fetus with isolated EB had trisomy, infection or cystic fibrosis. One fetus died in utero and one newborn died of a metabolic disease without digestive repercussions.

DISCUSSION AND CONCLUSION

The risk of trisomy 21 and the risk to have a serious disease appear low for the fetus with EB. It does not seem necessary to propose a systematic amniocentesis in case of isolated echogenic bowel.

Perinatal outcomes of fetal echogenic bowel

OBJECTIVE

To investigate perinatal outcomes of fetal echogenic bowel (FEB).

METHOD

This is a retrospective observational study of FEB cases from Jan 2005-Dec 2010. Data from ultrasound and fetal medicine investigations, uterine artery Doppler (UAD), intra-partum care and neonatal outcome were obtained from Fetal Medicine, Obstetric and Neonatal Databases.

RESULTS

There were 139 cases presenting at 21(+5) (15(+1) -35(+5) ) weeks gestation. Overall, 106/139 (76.2%) were live born (LB), 8/139 (5.8%) were complicated by intra-uterine deaths (IUD), 11/139 (7.9%) had termination of pregnancy (TOP) and 14/139 (10.1%) were lost to follow-up after 28 weeks gestation. Six had chromosomal/genetic abnormalities, two had congenital cytomegalovirus, none had cystic fibrosis.Uterine artery Doppler was normal in 106/130 (81.5%) cases. In this group, there were no cases of fetal growth restriction (FGR), 95/106 (89.6%) were LB, 1/106 (0.94%) had an IUD. In the abnormal UAD group, 17/24 (70.1%) developed FGR, 11/24 (45.8%) were LB, 4/24 (16.7%) had TOP, 7/24 (29.2%) had IUD.In total, 20/106 (18.9%) live births were admitted for specialist neonatal care, 12/20 (60%) for prematurity. Only one had primary bowel pathology.

CONCLUSION

Pregnancies with FEB and screen positive UAD are at risk of adverse perinatal outcome. Primary bowel pathology is rare following the finding of FEB.

Echogenic bowel on second-trimester ultrasonography: evaluating the risk of adverse pregnancy outcome

OBJECTIVE

To estimate if echogenic bowel diagnosed on second-trimester ultrasonography has an independent risk association with intrauterine growth restriction (IUGR) and intrauterine fetal demise.

METHODS

This is a retrospective cohort study of all patients with singleton gestations who presented to our institution for second-trimester ultrasonography between 1990 and 2008. Study groups were defined by the presence or absence of echogenic bowel. Primary outcomes were IUGR, defined as birth weight less than the 10th percentile for gestational age and intrauterine fetal demise at 20 weeks or more of gestation. Univariable and multivariable logistic regression analyses were used to estimate the risk of intrauterine fetal demise and IUGR in fetuses with echogenic bowel. Analyses were repeated after excluding cases of aneuploidy, cytomegalovirus (CMV) infection, other major congenital anomalies, and abnormal second-trimester serum screening results.

RESULTS

Of 64,048 patients, the incidence of echogenic bowel was 0.4%. Of these, echogenic bowel was an isolated finding in 188 (72.3%) cases. There were 579 (0.9%) cases of intrauterine fetal demise and 8,173 (12.8%) cases of IUGR in the entire cohort. After excluding cases of aneuploidy and CMV infection, the incidence of intrauterine fetal demise was 7.3% in the echogenic bowel group compared with 0.9% in the nonechogenic bowel group, translating to an absolute risk increase of 6.4%. The incidence of IUGR in the echogenic bowel group was 19.5% compared with 12.9% in the nonechogenic bowel group (absolute risk increase, 6.6%). After controlling for potential confounders, echogenic bowel was significantly associated with both intrauterine fetal demise (adjusted odds ratio [OR] 9.6, 95% confidence interval [CI] 5.8-15.9) and IUGR (adjusted OR 2.1, 95% CI 1.5-2.9). This risk association remained significant even when evaluating echogenic bowel as an isolated sonographic finding.

CONCLUSION

The presence of echogenic bowel on ultrasonography is independently associated with an increased risk for both IUGR and intrauterine fetal demise. Serial growth assessment and antenatal testing may be warranted in these patients.

Focus on cystic fibrosis and other disorders evidenced in fetuses with sonographic finding of echogenic bowel: 16-year report from Brittany, France

OBJECTIVE

Pregnancies medical follow-up and ultrasonography development have enabled detection of fetal echogenic bowel, a sign associated with various pathologies, including cystic fibrosis. Based on the long experience of a region where cystic fibrosis is frequent (Brittany, France), we describe disorders diagnosed in fetal echogenic bowel fetuses and assess ultrasonography ability in detecting cystic fibrosis in utero.

STUDY DESIGN

We reviewed the cases of fetal echogenic bowel diagnosed in pregnant women living in Brittany and referred for CFTR gene analysis over the 1992-2007 period (n = 289).

RESULTS

A disorder was diagnosed in 32.2% of the fetuses, cystic fibrosis being the most commonly identified (7.6%). We also found digestive malformations (7.0%), chromosomal abnormalities (3.7%), and maternofetal infections (3.7%). Combining these data with our ongoing newborn screening program since 1989 showed that ultrasonography enabled diagnosis of 10.7% of the cystic fibrosis cases.

CONCLUSION

This study highlights the importance of pregnancy ultrasound examinations and their efficiency in detecting cystic fibrosis.

Foetal magnetic resonance imaging and echogenic bowel

OBJECTIVES

To evaluate how foetal magnetic resonance imaging (MRI) may change the diagnosis in cases of ultrasound (U/S) findings of echogenic bowel (EB).

METHODS

Seventeen foetuses with EB underwent serial U/S examinations, foetal MRI, cystic fibrosis screening and maternal viral serologic tests. MRI protocol included T2-weighted half-Fourier acquired single-shot turbo spin-echo (HASTE) sequence and gradient echo (GE) T1-weighted images. Foetal abdominal MRI analyzed patterns were size and signal of small bowel, colon and rectum, ascites and abdominal mass. All neonates had complete clinical examination, abdominal sonography, and a 6 months clinical follow-up.

RESULTS

Eleven foetuses with isolated EB had normal MRI and normal outcome. In comparison, all the 6 foetuses whose U/S patterns showed associated signs had abnormal MRI (p < 0.001). Five had proven pathology (83.3%: 5/6) and only 1 (16.7%: 1/6) had no proven pathology and normal postnatal outcome (p = 0.001). For those five, foetal MRI showed bowel abnormalities with one case of bowel duplication and four cases of bowel obstruction. Two out of the four cases of bowel obstruction were genetically diagnosed as cystic fibrosis. The two remaining cases were diagnosed as ileal atresia.

CONCLUSION

MRI could provide additive information in cases of EB associated with bowel dilatation.

Intraabdominal fetal echogenic masses: a practical guide to diagnosis and management

Intraabdominal calcifications and other echogenic masses are relatively common findings during fetal sonography. Many are associated with no additional risk for the fetus or neonate. They may arise from the liver, gallbladder, spleen, kidneys, adrenal glands, gastrointestinal tract, or peritoneal cavity. Detection of such lesions should prompt a detailed survey for additional findings and a review of the maternal history. In some cases, fetal karyotyping may be indicated. In most cases, the diagnosis, management, and outcome are determined according to a combination of specific ultrasound appearances and at least one additional maternal or fetal factor. In utero diagnosis can often be achieved with careful evaluation of the lesion echotexture, associated calcifications, additional findings, and evolution over time. In most cases, expectant management is sufficient, but some patients require transfer to a facility where early postnatal intervention is available. A systematic approach to the findings aids in differential diagnosis and management.

Isolated Fetal Hyperechogenic Bowel Associated with Intra-Uterine Parvovirus B19 Infection

We report a case of fetal hyperechogenic bowel diagnosed at midgestation that was associated with fetal parvovirus B19 infection. Isolated hyperechogenic bowel was detected at 25 weeks. Cystic fibrosis, chromosomal abnormalities and cytomegalovirus infection were excluded, whereas polymerase chain reaction DNA for parvovirus B 19 was found positive on amniotic fluid. The hyperechogenic bowel decreased with complete resolution by 32 weeks of gestation. No other signs of fetal B19 infection were detected prenatally and the baby had normal postnatal outcome. This case provides additional arguments in favor of a possible intestinal tropism of parvovirus B19 during fetal life. Fetal B19 infection should be systematically incorporated in the prenatal evaluation of isolated fetal hyperechogenic bowel.

Controversial ultrasound findings

This article has reviewed a few of the more controversial findings in the field of obstetric ultrasound. For each one evidence-based strategies for the management of affected pregnancies have been suggested, derived from what the authors believe is the best information available. In some cases, this information is very limited, which can make counseling these patients extremely difficult. Some physicians find using specific likelihood ratios helpful in these complex discussions. An example of the relative likelihood ratios for several markers of trisomy 21 is illustrated in Table 10. Although the management of each of the findings discussed in this article is different, a few generalizations can be made. To begin with, the detection of any abnormal finding on ultrasound should prompt an immediate detailed ultrasound evaluation of the fetus by someone experienced in the diagnosis of fetal anomalies. If there is more than one abnormal finding on ultrasound, if the patient is over the age of 35, or if the multiple marker screen is abnormal, an amniocentesis to rule out aneuploidy should be recommended. Of the six ultrasound findings reviewed here, the authors believe that only echogenic bowel as an isolated finding confers a high enough risk of aneuploidy to recommend an amniocentesis in a low-risk patient. The other findings in isolation in a low-risk patient seem to confer only a modest increased risk of aneuploidy, if any, and this risk is certainly less than the risk of unintended loss from amniocentesis. Wherever possible, modifiers of this risk, such as maternal age, history, and first and second multiple marker screening, should be used to define more clearly the true risk of aneuploidy. As obstetric ultrasound moves forward, particularly into the uncharted waters of clinical use of three- and four-dimensional ultrasound, one can expect a whole new crop of ultrasound findings with uncertain clinical significance. Clinicians are well advised to await well-designed studies to determine the clinical significance of these findings before altering clinical care.

Quantitative assessment of fetal bowel echogenicity: comparison of harmonic, compound, and fundamental sonographic images

PURPOSE

The aims of this study were to assess normal fetal bowel echogenicity quantitatively and to compare the levels of bowel echogenicity observed with the use of 3 different sonographic image-processing techniques-harmonic plus compound imaging, harmonic imaging alone, and fundamental imaging-and 2 different broadband transducers.

METHODS

Women with normal singleton second-trimester fetuses underwent sonographic scanning with both a 2-5-MHz and a 4-7-MHz transducer. The use of the 3 imaging techniques and the 2 transducers resulted in 6 types of images: 2-5-HC (harmonic plus compound images), 2-5-H (harmonic images), and 2-5-F (fundamental images), and 4-7-HC, 4-7-H, and 4-7-F images. The relative echogenicities (brightness) of the fetal bowel and iliac bone were measured, and bowel echogenicity ratios (bowel echogenicity/iliac bone echogenicity x 100) were calculated using graphics software. The resulting data were analyzed to evaluate differences in echogenicity ratios between the 6 types of images.

RESULTS

We examined 37 fetuses during the study period. The bowel echogenicity ratios were highest on the images obtained with harmonic and compound-imaging techniques (2-5-HC, 84.7 +/- 23.4%; 4-7-HC, 98.5 +/- 36.4%). The bowel echogenicity ratio for the 2-5-HC images was significantly higher than those for the 2-5-H and the 2-5-F images (p < 0.01 and p < 0.001, respectively), and those for the 4-7-HC and 4-7-H images were higher than that for the 4-7-F images (p < 0.01 for both comparisons).

CONCLUSIONS

A sonographic finding of echogenic fetal bowel should be interpreted cautiously because the use of special image-processing techniques can artificially enhance the apparent level of echogenicity of the bowel. We recommend rescanning without the use of those techniques if the fetal bowel appears to have an increased level of echogenicity.

Cystic fibrosis in Greece: molecular diagnosis, haplotypes, prenatal diagnosis and carrier identification amongst high-risk individuals

Cystic fibrosis (CF) mutation analysis on 437 CF patients, characterized 80 different mutations (20 so far specific to our population) accounting for 91% of CF genes and generating 103 different genotypes. Eight mutations were common [F508del (53.4%), 621+1G>T (5.7%), G542X (3.9%), N1303K (2.6%), 2789+5G>A (1.7%), 2183AA>G (1.4%), E822X (1.4%), R1158X (1%)], 12 showed frequencies between 0.5% and 1%, while the remaining (60) were very rare (1 to 3 alleles). Denaturing gradient gel electrophoresis (DGGE) screening of 12 exons (3, 4, 7, 10, 11, 13, 14b, 16, 17b 20 and 21) detected 85.5% of CF alleles. Haplotypes for eight diallelic and three microsatellite markers have been characterized for the common, a few rare and novel Greek mutations. Results of 165 prenatal diagnoses (including 49 due to bowel hyperechogenicity), testing a total of 41 different parental genotypes, are reported. One hundred and sixteen prenatal tests resulted in 22 affected, 59 heterozygous, 34 normal fetuses and one incomplete diagnosis. Of the 49 echogenic bowel fetuses, 3 were heterozygotes. Carrier screening was initiated, with emphasis on individuals and couples in high-risk groups - with a family history of CF, one partner with CF, and couples with male infertility seeking in vitro fertilization (IVF). Mutation analysis on 672 individuals (120 couples, 91 unaffected CF siblings, 283 CF family relatives and 58 general population subjects), identified a total of 176 heterozygotes and 7 couples where both partners were CF heterozygotes. Prenatal diagnosis was performed in 4 cases and 3 were counseled on the availability of a prenatal test.

Use of genetic sonography for adjusting the risk for fetal Down syndrome

Systematic evaluation of ultrasound findings known to be associated with trisomy 21, at an appropriate gestational age, has been referred to as a genetic sonogram. A number of high-risk centers performing genetic sonography have reported detection of ultrasound abnormalities in the majority of fetuses with fetal Down syndrome. However, nonspecific markers are more commonly observed than structural abnormalities, which are detected in less than 20% of cases in a nonselected population. Also, the actual sensitivity of a genetic sonogram will depend on various factors including the markers sought, gestational age, reasons for referral, and of course the quality of the ultrasound. Appropriate use of a genetic sonogram can help to modify the risk of fetal Down syndrome by decreasing the risk when the ultrasound is normal, or increasing the risk when specific ultrasound markers are detected. The postultrasound risk can be estimated by applying specific likelihood ratios, reflecting the strength of individual markers, with the a priori risk based on maternal age alone, or combined with biochemical markers when known. We review this approach of age-adjusted ultrasound risk assessment for fetal Down syndrome and illustrate how the risk can be estimated. Individual sonographic markers are also discussed.

Prenatal diagnosis for paediatricians

In Ontario, approximately 140,000 women deliver newborn infants each year. Of these women, 60,000 to 70,000 have multiple marker screening, 10,000 undergo amniocentesis or chorion villus sampling and virtually all have at least one prenatal ultrasound. Multiple marker screening is not used in every province and territory; however, amniocentesis and prenatal ultrasound are used throughout Canada. Most paediatric patients will have been exposed to some form of prenatal diagnosis. If an abnormality is found prenatally, parents may have concerns to discuss with the paediatrician after the child is born. Likewise, if a child with a problem is born following a normal pregnancy, the parents will want to know why the problem was missed prenatally. Paediatricians should be aware of prenatal tests that have been performed to understand better their patients and their families.

Hyperechogenic fetal bowel and Down syndrome. Results of a French collaborative study based on 680 prospective cases

Hyperechogenic fetal bowel is prenatally detected by ultrasound during the second trimester of pregnancy in 0.1% to 1.8% of foetuses. It has been described as a normal variant and has often been associated with severe diseases, notably Down syndrome. The aim of the present study was to determine the risk of trisomy 21 in a prospective study of 680 fetuses with hyperechogenic foetal bowel. Karyotyping was performed on amniotic cells in 632 cases, and outcome was known in 655 cases. A 2.5% risk of Down syndrome and a 1% risk of other severe chromosomal anomalies were observed. Hyperechogenicity was isolated in 11/17 Down syndrome cases, and associated with other ultrasound anomalies in all seven cases of severe chromosomal anomalies. In conclusion, fetal bowel hyperechogenicity indicates a risk of chromosomal anomalies ten-fold higher than that expected on the basis of maternal age, therefore justifying invasive procedures.

Factors associated with fetal demise in fetal echogenic bowel

OBJECTIVE

The purpose of this study was to determine risk factors associated with intrauterine fetal demise in fetuses with unexplained echogenic bowel that is diagnosed in the second trimester.

STUDY DESIGN

A retrospective case-control study compared fetuses with echogenic bowel and fetal demise with fetuses with echogenic bowel who were live born. Fetuses affected with cystic fibrosis, aneuploidy, or congenital infection and fetuses diagnosed with major anomalies were excluded. Variables examined in the determination of risk factors for intrauterine fetal demise included intrauterine growth restriction, oligohydramnios, elevated maternal serum alpha-fetoprotein levels, and elevated maternal serum beta-hCG levels. Statistical analysis was performed with the Fisher exact test, Student t test, and logistic regression analysis.

RESULTS

One hundred fifty-six fetuses met the inclusion criteria. There were 9 cases of intrauterine fetal demise and 147 live born control fetuses. The median gestational age of intrauterine fetal demise was 22.0 weeks (range, 17-39 weeks). Intrauterine growth restriction occurred more frequently in cases of intrauterine fetal demise than in live born infants (22.2% vs 0.7%; P =.009), as did oligohydramnios (44.4% vs 2.0%; P <.001) and elevated maternal serum alpha-fetoprotein levels (80.0% vs 7.7%; P: =.001). With the use of logistic regression analysis, elevated maternal serum alpha-fetoprotein was the strongest independent risk factor that was associated with intrauterine fetal demise (odds ratio, 39.48; 95% CI, 11.04%-141.25%).

CONCLUSION

In our series, there was a 5.8% incidence of intrauterine fetal demise in fetuses with unexplained echogenic bowel. Elevated maternal serum alpha-fetoprotein is the strongest predictor of fetal demise in fetal echogenic bowel.

Trisomy 21. Second-trimester ultrasound

Not every aspect of sonographic examination reveals karyotypic abnormalities. Ultrasound examination of a fetus with trisomy 21 generally reveals normal amniotic fluid, normal placentation, and normal fetal growth. In addition, other chromosomal abnormalities have many of the same sonographic findings as Down syndrome, and many findings have a large overlap with phenotypically normal fetuses. The importance of second-trimester ultrasound screening for Down syndrome has remained great because of its ease of use and relative effectiveness. Trained sonographers can adjust the relative risk for trisomy 21 and alter the need for genetic amniocentesis. It is important that parents understand the limitations of a screening test and the risks and benefits of possible subsequent confirmatory testing. If a major structural abnormality is identified on ultrasound, karyotype determination should be considered. Nuchal thickness in the first or second trimester remains the most clinically useful marker for trisomy 21. The predictive value of all the markers depends on the population studied and can be modified by a host of biochemical markers and historical factors. If fetal karyotype analysis could be performed without sampling through the uterus, prenatal diagnosis could be offered to all pregnant women, and screening would be unnecessary. Despite its limitations, ultrasound will have an important role in prenatal diagnosis at least until isolating and testing fetal cells from maternal blood or other sources becomes practical and widely available. Whether used alone or in conjunction with additional biochemical or molecular serum markers, ultrasound is an important and powerful tool in prenatal genetic evaluation.

The value of minor ultrasound markers for fetal aneuploidy

As a result of improvements in ultrasound image quality and scanning technique, an increasing number of subtle morphological changes in fetal anatomy have been identified in the second trimester. Most of these ultrasound features were originally described as normal variants of development with no clinical significance. However, subsequent studies in high-risk populations showed that some of these variants were more prevalent in fetuses with chromosomal defects and therefore proposed as prenatal markers for the detection of aneuploidy. The implications for pregnancy management when one of these so-called minor ultrasound markers is detected have been a matter of continuous controversy in the field of prenatal diagnosis and yet the definitive answer on their clinical significance in the low-risk population is still debated.