Amnion rupture sequence in previable fetuses

Amniotic band syndrome and limb body wall complex in Europe 1980-2019

Amniotic band syndrome (ABS) and limb body wall complex (LBWC) have an overlapping phenotype of multiple congenital anomalies and their etiology is unknown. We aimed to determine the prevalence of ABS and LBWC in Europe from 1980 to 2019 and to describe the spectrum of congenital anomalies. In addition, we investigated maternal age and multiple birth as possible risk factors for the occurrence of ABS and LBWC. We used data from the European surveillance of congenital anomalies (EUROCAT) network including data from 30 registries over 1980-2019. We included all pregnancy outcomes, including live births, stillbirths, and terminations of pregnancy for fetal anomalies. ABS and LBWC cases were extracted from the central EUROCAT database using coding information responses from the registries. In total, 866 ABS cases and 451 LBWC cases were included in this study. The mean prevalence was 0.53/10,000 births for ABS and 0.34/10,000 births for LBWC during the 40 years. Prevalence of both ABS and LBWC was lower in the 1980s and higher in the United Kingdom. Limb anomalies and neural tube defects were commonly seen in ABS, whereas in LBWC abdominal and thoracic wall defects and limb anomalies were most prevalent. Twinning was confirmed as a risk factor for both ABS and LBWC. This study includes the largest cohort of ABS and LBWC cases ever reported over a large time period using standardized EUROCAT data. Prevalence, clinical characteristics, and the phenotypic spectrum are described, and twinning is confirmed as a risk factor.

Fetoscopic surgery for amniotic band syndrome: Case series

We aimed to evaluate the fetoscopic procedure indications, procedure-related complications, and neonatal outcomes in cases diagnosed with amniotic band syndrome (ABS). Stage II and III cases according to Hüsler classification were included for fetoscopic surgery. Scissors were used to release the amniotic band in six cases, and a diode laser was used in one case. A single entry was made in all cases. The majority of the children acquired a functional limb (71.4%). Fetal morbidity was mainly linked to the consequences of preterm premature rupture of the membranes (57.1%) and preterm birth (28.5%). Excluding complicated cases, fetoscopic band release is encouraging in cases of ABS in the limbs.

Fetoscopic Release of Amniotic Band Syndrome: An Update

Amniotic band syndrome is a rare condition. There have been few cases reported of fetoscopic band dissection. The aim of this case series is to report 3 cases of fetoscopic treatment for amniotic band syndrome, including indication for surgery, technical aspects, complications and outcomes. Fetoscopic treatment was performed respectively at 23 ^5/7 , 26 ^5/7 and 18 ^3/7 weeks' gestation. Two procedures were performed with a laser fiber through a single trocar whereas one surgery was performed with scissors. In conclusion, fetoscopic release of the amniotic bands in case of amniotic band syndrome is feasible with encouraging results in order to prevent amputation and dysfunction of the extremities.

Outcomes of prenatally diagnosed spontaneous chorioamniotic membrane separation in singleton pregnancies: A systematic review of case series and case reports

OBJECTIVES

To provide an overview of perinatal outcomes in prenatally diagnosed spontaneous chorioamniotic separation (sCAS).

METHODS

A systematic search of the literature was performed from inception to July 2019, including PubMed, Ovid MEDLINE, and Ovid EMBASE. All studies reporting prenatally diagnosed sCAS after 16 weeks' gestation in singleton pregnancies were eligible. Two independent reviewers used standardized forms for data abstraction.

RESULTS

Of 408 screened abstracts, 17 studies reporting 118 cases of sCAS were included. Among 113 cases with delivery outcomes, preterm birth (PTB) occurred in 60 (53.1%, 95% confidence interval [CI] 43.9-62.3%). Intrauterine fetal demise (IUFD) occurred in seven (6.2%, 95% CI 1.8-10.6%) cases, with four due to cord strangulation. Spontaneous abortion occurred in one (0.88%, 95% CI -0.84-2.6%) case. Among 104 cases with postnatal follow-up, there were six (5.8%, 95% CI 1.3-10.3%) neonatal deaths and one (0.96%, 95% CI -0.91-2.8%) infant death. Perinatal mortality (IUFD and neonatal deaths) was 11.0% (95% CI 5.4-16.7%).

CONCLUSIONS

sCAS may be associated with increased risk of PTB, however, the available data are largely case reports and series. Antepartum surveillance after viability can be considered due to risk of cord accidents. Prospective study is necessary to understand the clinical implications of sCAS.

The Anaesthesiologist and Palliative Care in a Newborn with the Adam "Sequence"

Reports focusing on biomedical principlism and the role of anaesthesiologists in palliative care are rare. We present the case of a newborn with multiple craniofacial anomalies and a diagnosis of ADAM “sequence,” in which surgical removal of placental adhesions to the dura mater and the correction of meningocele was not indicated due to the very short life expectancy. After 48 hours, the odor from the placenta indicted a necrotic process, which prevented the parents from being close to the child and increased his isolation. Urgent surgery was performed, after which the newborn was transported to the ICU and intubated under controlled mechanical ventilation. The patient died a week later. The principles of beneficence, nonmaleficence, justice, and respect for autonomy are simultaneously an inspiratory and regulatory framework for clinical practice. Although only necessary procedures are defended, which suggests a position contrary to invasive interventions at the end of life, sometimes they are the best palliative measures that can be taken in cases like the one described here.

The prevalence of amnion rupture sequence, limb body wall defects and body wall defects in Alberta 1980-2012 with a review of risk factors and familial cases

Prevalence rates of amnion rupture sequence, limb body wall defect, and body wall defects vary widely. Comparisons are difficult due to small case numbers and the lack of agreement of definition, classification, and pathogenesis. This study reports the prevalence of cases classified in five distinct categories. The Alberta Congenital Anomalies Surveillance System data on live births, stillbirths, and terminations of pregnancy (<20 weeks gestation) occurring between 1980 through 2012 with the ICD-10 Royal College of Paediatrics and Child Health Adaptation codes used for congenital constriction bands (Q79.80) and body wall complex (Q89.7) were reviewed. During the 33-year-study period, there were 153 eligible cases ascertained from 1,411,652 live births and stillbirths, giving a prevalence of 1.08/10,000 total births. There were more males (52%) than females (45%) and 3% were of unknown sex. The average maternal age, birth weight, and gestation was 27 years, 2,701 g, and 35 weeks, respectively. Limb deficiencies occurred in 78% of cases. Amniotic bands with limb deficiency was the most common phenotype (48%). Digital limb deficiency was the most frequent type (56%); however, cases with body wall defects had more severe types of limb deficiencies. The upper limbs only were affected more times (44%), and there was no side preference. Most cases are sporadic but a number of familial occurrences have been reported although some have insufficient documentation and others misdiagnosed. A review of putative risk factors gives conflicting results. © 2016 Wiley Periodicals, Inc.

Novel techniques for the surgical management of abdominopelvic constriction rings in amniotic band syndrome

Constriction rings are associated with amniotic band syndrome and most often present in the extremities. Constriction bands of the trunk are rare, and a standard of surgical care remains elusive. Traditional methods of constriction ring excision rely on soft-tissue rearrangement with multiple Z-plasties, but renewed interest in linear closure and limited Z-plasty has emerged. The authors review contemporary literature and report two cases of abdominopelvic constriction ring reconstruction with long-term follow-up. Novel techniques including anterior sheath Y-V plasty, pteruges release of the Scarpa fascia, and limited Z-plasty closure may minimize the need for serrated scar patterns.

ADAM "sequence" part II: hypothesis and speculation

Noted for centuries in humans, a relatively hairless mammal [e.g., Hallero, 1766; Hohl, 1828 in Klunker, 2003], the so-called amniotic deformities, adhesions, mutilations (ADAM) sequence remains causally and pathogenetically incognito. In 1930 Streeter stated " apodictically" that no evidence has been found that intra-uterine amputation is due to amniotic bands or adhesions …" and that his 16 cases provided (histological) evidence for a "germinal origin." He concluded that an amniotic cord was "not an adhesion or inflammatory product but … an anomalous developmental structure and present from the outset." In survivors the "traces" of damaged limb-buds "reveal the scars of poor germ-plasm." In 1958, Willis, in dismissing the amniotic origin of the ADAM defects (or "Streeter" or "Simonart" bands) quoted Keith [1940] to the effect that "(a)mniotic adhesions … are always produced by … the fetus – as a result of dysplasia in foetal tissues. They are the result, not the cause, of foetal malformations." Streeter [1930] mentions a potential familial case (56-year-old man and his mother), not controlled by photographs or other records and concluded "that the (ADAM) deformity is not easily transmissible," but "due to the constitution of the germ-plasm." Torpin [1968] concluded, as apodictically as Streeter and Willis, that "… proof of amnion rupture without damage to the chorionic sac is no longer "in question." Considering Torpin's decades-long study of the ADAM phenomenon and review of 494 references (missing many) it is surprising that he does not discuss the relationship between the apparent ADAM defects and other, internal anomalies that maybe present in an affected fetus or infant not evidently caused by the amniotic disruptions, adhesions or mutilations, unless his mind was made up. Our review of these internal and other presumed primary malformations in ADAM is ongoing. However, on a preliminary basis, it seems likely to us that: (1) there is an increased prevalence of such primary anomalies in the ADAM condition confirming the view and experience of others, for example Czeizel et al. [1993]; (2) these malformations (e.g., heterotaxy) may arise as early as gastrulation; (3) that, given the ADAM phenomenon is exclusively ascertained as the ADAM phenotype in fetuses and infants, that is, that its cause and ascertainment are completely congruent, then the apparent amniotic defect must also be regarded as a malformation; (4) that in such a case the ADAM phenomenon with associated primary malformation(s) is a form of syndromal pleiotropy due to one cause yet to be elucidated. To that end we recommend archiving DNA from all affected fetuses coming to autopsy and their parents and placentas and surgical tissues of all viable affected infants for ultimate exome or genome sequencing perhaps with special attention to the syncytin genes.

Pathology of the stillborn infant for the general pathologist: part 1

As the information obtained from previable fetal and stillbirth autopsies is used not only to explain the loss to the parents, but for future pregnancy planning, general pathologists need to be comfortable in dealing with these autopsies. The importance of an adequate fetal examination has been emphasized in a recent policy on the subject by the American Board of Pathology http://www.abpath.org/FetalAutopsyPolicy.pdf. This review paper covers the approach to the fetal and stillbirth autopsy. This first article covers the approach to the nonanomalous and anomalous autopsy. Hydrops fetalis will be covered in the second part of this series to be published subsequently.

[Complex of amniotic deformities, adhesions, mutilations: Endless debate]

Amniotic deformities, adhesions, mutilations (ADAM) complex is a broad heterogeneous spectrum of congenital anomalies. ADAM complex is characterized by constriction rings, amputation of fingers or limbs and the presence of the amniotic band. However, it may also involve craniofacial disruptions, body wall defects and internal organ abnormalities. The aim of this review is to present the results found in regard to ADAM complex from its historical background, clinical manifestations, epidemiology, etc. In particular, our attention was focused on demonstrating the varying etiopathogenesis theories of ADAM complex and their contradictions. The study was conducted using the databases of PubMed, EBSCO host, Ovid, SpringerLink, Scopus, nature.com, JAMA and ScienceDirect with the following keywords for the search: "amniotic band syndrome", "amniotic band sequence", "Streeter dysplasia", "ADAM complex". In this study we used 22 full-text articles. Patients with ADAM complex require a complete pre- and postnatal evaluation to integrate the diagnosis and to decide on timely treatment. It is important for clinicians and surgeons to possess knowledge of this entity. Further research is necessary to establish a nosological basis.

Prenatal MRI evaluation of limb-body wall complex

BACKGROUND

The sonographic (US) features of limb-body wall complex have been well documented; however the literature regarding the findings on MRI in limb-body wall complex is scant.

OBJECTIVE

To characterize the prenatal MRI features of limb-body wall complex.

MATERIALS AND METHODS

We performed a retrospective review of all MRI scans of fetuses diagnosed with limb-body wall complex at our institution from 2001 to 2011. Fetuses without correlating US scans or follow-up information were excluded. Three pediatric radiologists blinded to the specific US findings reviewed the prenatal MRIs. Images were evaluated for the organ location and attachment, the body part affected, characterization of the body wall defect, and spinal, limb and umbilical cord abnormalities.

RESULTS

Ten subjects met inclusion criteria. MRI was able to detect and characterize the body part affected and associated abnormalities. All fetuses had ventral wall defects, a small thorax and herniated liver and bowel. The kidneys were extracorporeal in three cases. The extruded organs were attached to the placenta or the uterine wall in all cases. Abnormal spinal curvatures of various degrees of severity were present in all cases. Eight cases had a short, uncoiled cord. Limb anomalies were present in 6 of the 10 cases.

CONCLUSION

We illustrate the common fetal MRI findings of limb-body wall complex. The prenatal diagnosis of limb-body wall complex and the differentiation of this defect from treatable abdominal wall defects are crucial to providing appropriate guidance for patient counseling and management.

Limb-body wall defect: experience of a reference service of fetal medicine from Southern Brazil

BACKGROUND

Limb-body wall defect is a rare condition characterized by a combination of large and complex defects of the ventral thorax and abdominal wall with craniofacial and limb anomalies.

METHODS

The aim of this study was to describe the experience of our fetal medicine service, a reference from Southern Brazil, with prenatally diagnosed patients with a limb-body wall defect in a 3 years period. Only patients who fulfilled the criteria suggested by Hunter et al. (2011) were included in the study. Clinical data and results of radiological and cytogenetic evaluation were collected from their medical records.

RESULTS

Our sample was composed of 8 patients. Many of their mothers were younger than 25 years (50%) and in their first pregnancy (62.5%). It is noteworthy that one patient was referred due to suspected anencephaly and another due to a twin pregnancy with an embryonic sac. Craniofacial defects were verified in three patients (37.5%), thoracic/abdominal abnormalities in 6 (75%) and limb defects in eight (100%). Congenital heart defects were observed in five patients (62.5%). One of them presented a previously undescribed complex heart defect.

CONCLUSION

The results disclosed that complementary exams, such as MRI and echocardiography, are important to better define the observed defects. Some of them, such as congenital heart defects, may be more common than previously reported. This definition is essential for the proper management of the pregnancy and genetic counseling of the family. The birth of these children must be planned with caution and for the prognosis a long survival possibility, despite unlikely and rare, must be considered.

Preventing misdiagnosis in amniotic band sequence: a case report

Amniotic band sequence (ABS) is an uncommon and heterogeneous congenital disorder caused by entrapment of fetal parts by fibrous amniotic bands, causing distinctive structural abnormalities involving limbs, trunk, and craniofacial regions. The incidence ranges between 1/1200 and 1/15,000 live births, but is higher in stillbirths and previable fetuses. The intrinsic theory attributes the constriction band syndrome as an inherent development defect of embryogenesis while the extrinsic theory proposes that an early amnion rupture is responsible for the adherent bands. It is also suggested that amputations and constriction rings might be due to vascular disturbances. Anomalies resulting from amniotic bands are quite variable and sometimes may simulate chromosomal abnormalities. The authors report a case of a 36-week-gestation male neonate who lived for 29 hours after a vaginal delivery with an Apgar score of 8/9/9. The mother was primipara, and the prenatal was uneventful except for two episodes of urinary tract infections. The newborn examination depicted multiple anomalies characterized by exencephaly, bilateral labial cleft with distorted nostrils and palate cleft. There was also facial skin tag band, exophthalmos with hypoplasia of the eyelids. The limbs showed distal amputation of the fingers in both hands and feet, oligodactyly associated with syndactyly in the left foot, ring constriction in the right leg, the presence of right hyperextension, and clubfoot. The upper limbs showed length discrepancies. Karyotype analysis was normal at 46 XY. The authors conclude that the recognition of the malformations secondary to ABS is important in genetic counseling to prevent misdiagnosis between chromosomal and secondary disruption disorders.

Development of a fetal rabbit model to study amniotic band syndrome

Amniotic band syndrome (ABS) is a group of fetal malformations caused by fibrous adherences. Species such as sheep, rats, and mice have been used to study this syndrome. We developed a fetal rabbit model using 24 fetuses from punctured uteri. We found one case of syndactyly, one case of amniotic banding, two cases of extremity deformities, one case of a tail deformity, one case of head compression, and one case of open eyelids. Other malformations have been described in an amnion rupture sequence model (exencephaly and cleft palate). The rabbit fetus is an adequate model in which to develop this syndrome.

Limb-body wall defect. Is there a defensible hypothesis and can it explain all the associated anomalies?

Aside from gastroschisis and omphalocele, major defects of the ventral body (thoracoabdominal) wall are relatively uncommon and almost universally lethal. They are most often associated with other anomalies including those of the limbs that may range from amelia to mild positional deformations, unusual craniofacial malformations, and a variety of visceral abnormalities that include the heart, lungs, genitourinary system, and gut. This complex of ventral wall anomalies has been discussed under a broad and changing nomenclature that has included amniotic band disruption complex, amnion rupture sequence, limb-body wall defect (or complex), and simply body wall complex. Three major theories have been suggested to explain this complex: early amnion rupture (operating through uterine pressure and/or disruption by amniotic bands), vascular compromise (primarily hypoperfusion), and an early intrinsic defect of the developing embryo. We present four patients that illustrate the spectrum of ventral body wall defects, and from there critique the current hypotheses of pathogenesis. We conclude that this association of malformations originates as early as the embryonic disc stage, and that some of the observed associated anomalies are secondary complications of the primary disturbance in embryogenesis. We propose a new explanation for the atypical facial clefts and cranial malformations that are often observed.

Revisiting acrania: same phenotype, different aetiologies

OBJECTIVE

To evaluate the contribution of prenatal and postmortem examinations in establishing the aetiology of acrania.

METHODS

Retrospective evaluation of 14 cases of acrania managed through elective termination of pregnancy.

RESULTS

The median maternal age was 30 years (range 18-40) and median gestational age at diagnosis was 13 weeks (range 12-15). One mother had epilepsy and was taking anticonvulsants and another had uncontrolled type II diabetes mellitus. Only 3 women were using folic acid at conception. Chromosomal abnormalities were detected in 3 of 8 cases analyzed. Unilateral anopthalmia, cervical rachischisis, midline facial and limb defects coexisted with acrania in 4 cases. Acrania with craniofacial dysmorphism and asymmetrical finger amputation were observed in a case of amniotic band syndrome. A previous history of anencephaly was documented in 1 case.

CONCLUSION

Acrania is a characteristic phenotypic expression of a variety of different aetiologies. Investigation with cytogenetic studies and postmortem are essential to provide a definitive answer. This will provide a better understanding of the underlying aetiology and help establish the recurrence risk for future pregnancies.

Amniotic band syndrome and/or limb body wall complex: split or lump

Six cases of amniotic band syndrome/limb body wall complex were studied in respect to clinicopathologic characteristics. The diagnosis was based on two out of three of the following manifestations: cranio facial clefts; limb body wall defects and amniotic band attachment. Four cases were stillborn and associated with internal defects, including central nervous system. Two cases had facial and limb defects and were live born (3-5 years old at examination). Phenotypic features of the stillborn cases were craniofacial clefting, thoracoabdominoschisis, amputation, ring constriction, amniotic band adhesion, placental adhesions, and internal malformations. Histology of bands revealed fibroconnective tissue as well as flattened epithelial cells together with neuroectodermal elements. Umbilical cord section revealed an abnormal number of vessels. When analyzing the observed data in relation to their etiology, it was found that amniotic disruption, vascular disruption or genetic disruption could explain the amniotic band syndrome/limb body wall complexes, alone or in combinations. A brief review of literature in search of pathogenesis is offered along with an etiopathogenetic model.

Transverse limb reduction and intrauterine device: Case report and review of the literature

BACKGROUND

Pregnancies with an intrauterine device (IUD) in situ are associated with increased maternal and foetal morbidity and mortality. No proven teratogenetic effects have been attributed to IUDs.

CASE

A 29-year-old-woman conceived with an IUD in place. The device was removed at 7 weeks' gestation. Her level 2 sonogram at 25 weeks' gestation revealed transverse limb reduction of the foetal right forearm. She gave birth at term to a female infant with reduction of the right forearm. The rest of the physical examination, imaging and laboratory tests, including serology and karyotype were normal.

CONCLUSION

We present a rare case of transverse limb reduction defect associated with the presence of an IUD at the time of conception. The device had been removed in the first trimester of the pregnancy. Data from the literature are reviewed.

Comparison of the amniotic band disruption complex with acardiac twins does not support its vascular origin

The amniotic band disruption complex (ABDC) has been attributed to vascular disruption by some authors, not by others. Acardiac twins (ATs), however, have been generally accepted as a prime example of vascular disruption. In this study a comparison was made of these two entities to determine if they were similar or not, and thus we attempted to resolve the controversy of the mechanisms in the ABDC. A female tendency (2:1) was found in the ABDC in contrast to the "normal" sex distribution (0.88:1) in the ATs (p < 0.001). Most types of malformations (66%) were mutually exclusive, notably those of the cranium/brain, abdominal wall, and most internal organs; 83% were more significantly related to one or other of the entities. The ABDC malformations tended to occur unilaterally, but in the ATs they occurred bilaterally (p < 0.0001); the former tended to involve external organs and the latter internal organs (p < 0.0001). With so many differences, the two entities are unlikely due to the same mechanism: the ABDC is more likely to be due to external disruption.

Amniotic Band Syndrome with Limb Amputation after Exposure to Mifepristone in Early Pregnancy

To date, the number of cases reported after exposure to mifepristone alone in early pregnancy is limited. In 24 cases, only 1 observation of fetal malformation associated with mifepristone has previously been reported. We report a case of amniotic band syndrome with limb amputation after exposure to mifepristone in early pregnancy. This association raises the question of a possible causal relationship.

Chromosome abnormalities identified in 347 spontaneous abortions collected in Japan

OBJECTIVE

We determined the incidence of specific chromosome abnormalities in this Japanese population so that comparisons could be made to the incidence of chromosome abnormalities reported for other populations.

METHODS

A total of 423 cases of products of conception aborted spontaneously were collected for cytogenetics analysis from various medical sites located in Japan. The cytogenetic results, along with clinical information including gestational age at the time of the miscarriage and maternal age, were compiled in a database. The incidence of specific chromosome aberrations was determined. The abnormalities were separated by gestational age at the time of the miscarriage and by maternal age.

RESULTS

The total number of specimens available for cytogenetic analysis was 407. Cytogenetic results were obtained for 347 cases (85.3%), of which 196 (56.5%) showed chromosome abnormalities. Autosomal trisomy was detected in 120 cases (61.2% of the abnormal cases). Trisomy for each autosome, with the exception of chromosomes 1, 5, 6, 11, 12, and 19, was identified. The most common autosomal trisomy was that of chromosome 16 (30 cases), followed by trisomy 21 (13 cases), and trisomy 22 (13 cases). Eight cases showed double trisomies, and one case showed trisomy for three different chromosomes. Two cases showed monosomy 21, and 24 cases showed 45,X. Triploidy was identified in 27 cases and tetraploidy was detected in five cases. Unbalanced structural rearrangements were found in 11 cases, and balanced translocations were identified in two cases. Six cases showed mosaicism: three cases showed a normal cell line; and three cases had multiple abnormal cell lines. Separating the trisomies by the gestational age at which time the miscarriage occurred revealed that trisomies 7, 8, 14, 15, 16 and 22 occurred exclusively during the first trimester and fetuses with trisomies 4, 13, 18 and 21 survived late into the second trimester.

CONCLUSION

Overall patterns of chromosome abnormalities detected in spontaneous abortions in Japan were similar to those reported in the literature.

Strangulation of the umbilical cord due to combined amniotic band and true knot

A case of fetal death due to an amniotic band and an umbilical cord true knot is presented. To the best of our knowledge the simultaneous occurrence of true knot of cord and amniotic band has never been previously reported and may shed light on the possible time of true knot formation in this case.

Amnion rupture sequence in a first trimester missed abortion

We report the diagnosis of amnion rupture sequence made by sonography and fetoscopy during the first trimester of gestation in a case of missed abortion. The investigation revealed a demised fetus with the characteristics of 9 weeks of development. The early fetus had an amnion adhesion at the tip of the nose and strands of amnion wrapped around the terminal phalanges of both feet. No defects in addition to the face and limb involvement were identified. The karyotype was normal: 46,XX. In the reported case, fetoscopy allowed confirmation of the sonographic diagnosis of an amnion rupture sequence in the first trimester of gestation and consequently helped to clarify the cause of abortion in this case of early fetal demise.

Limb-body wall complex: 4 new cases illustrating the importance of examining placenta and umbilical cord

Limb-body wall complex (LBWC) is a rare, sporadic, congenital defect defined as a combination of at least two of three characteristics: 1. limb defects, 2. anterior body wall defects, and 3. exencephaly or encephalocoele with/without facial clefts. Three pathogenic mechanisms have been proposed: early amnion rupture, vascular disruption and embryonic dysgenesis. In this study we carried out the pathological evaluation of four fetuses with LBWC and their placentas. None of the cases had craniofacial defects. Three fetuses showed an abdominal wall defect with eventration of abdominal organs, cloacal exstrophy, absent external genitalia, abnormal internal genitalia, scoliosis and lower limb defects. One fetus showed failure of closure of both thoracic and abdominal walls with ectopia cordis, evisceration of left lung and abdominal organs, severe reduction defect of left arm, but normal colon, anus, bladder, genitalia and lower limbs. All cases had a short, malformed umbilical cord, incompletely covered by amnion. The umbilical vessels were embedded in an amniotic sheet which connected the skin margin of the anterior body wall defect to the placenta. These anomalies suggest an abnormal body stalk development as a pathogenic mechanism for LBWC. Prenatally, the abnormal fetoplacental attachment can be detected ultrasonographically by the end of the first gestational trimester. Postnatally, the examination of placenta, umbilical cord and membranes is crucial in confirming the diagnosis of LBWC.

Fetal amniotic adhesions. Their topographic concordance with regionally clustered malformations

BACKGROUND

The amniotic band disruption complex (ABDC) has been segregated recently into various phenotypes. In view of the pathogenic mechanisms that have been proposed, this study was designed to assess if it is one variable process or is composed of several distinct complexes.

METHODS

The 48 cases of fetuses with bands or placenta attached to fetal parts cited in this paper included nine new cases and 39 from the literature. They were organized first according to the embryonal topography of the malformations, then according to the position of the adhesions, and finally by the assessment of distances between the cases and between the malformations using the squared Euclidean distances for binary variables and cluster analysis.

RESULTS

In all three analyses, three groups were identified: 1) fetuses with cephalo-thoracic anomalies; 2) fetuses with caudal anomalies, and 3) fetuses with mixed anomalies. Nonetheless, overlap among the three groups was apparent. Thus, while fetuses with amniotic bands form three clusters, it appears that these are part of a spectrum and should be considered as variable manifestations of a single entity resulting from a single pathogenetic mechanism. An association was established between the localization of the adhesions and the malformations in various axes. Abdominoschisis, however, was not particularly related to adhesions at one or the other end of the fetus; a short umbilical cord was an almost universal finding. Single umbilical artery (SUA) was especially related to caudal adhesions and malformations (p = 0.004 and 0.001), as well as abdominoschisis (p = 0.002) and agenesis of the abdominal organs (p = 0.008).

CONCLUSIONS

The association between amniotic adhesions to the fetus and multiple malformations occurring predominantly in the same area suggest that the former are the cause of the latter. The association of abdominoschisis, as well as a short umbilical cord, with malformations and adhesions in all areas, suggests that these are secondary phenomena to generalized embryonal and fetal tension. SUA, however, with a specifically regional association, is more likely to be due to disruption from exposure in cases with abdominoschisis, often accompanying the loss of abdominal organs.

Body stalk defects, body wall defects, amniotic bands with and without body wall defects, and gastroschisis: comparative epidemiology

The presence of body wall defects with "evisceration" of thoracic and/or abdominal organs associated with other congenital anomalies, with or without limb deficiencies, is considered to be the body wall complex (BWC). The BWC is different from gastroschisis, which is usually a small body wall defect lateral to the umbilical cord that is not covered by any membrane and, in most of the cases, is an isolated defect. For the present analysis we separated the BWC group into three subgroups. One group was that of body stalk anomalies characterized by severe defects of the abdominal wall with absence of, or very small, umbilical cord, or this is continuing with the placenta. The second group was made up of those infants with body wall defects without amniotic bands, and the third group was of those children with body wall defects produced by amniotic bands. We considered two additional groups in the analysis, one was of infants with gastroschisis and the other those infants with amniotic bands without body wall affectation. We also included the control group (nonmalformed infants) for comparisons. From the results of our epidemiological study, we can conclude that amniotic bands with body wall affectation and amniotic bands without body wall defects are two different entities. The results also suggest that the characteristics of infants with amniotic bands with body wall defects are more similar to the group of infants with body stalk anomalies. This may indicate that the former group is produced during the very early gestation.

Clinical and epidemiological characteristics of infants with body wall complex with and without limb deficiency

The spectrum of defects in cases with limb body wall complex (LBWC) is quite variable since other anomalies are also observed in infants with LBWC, and some cases do not have limb deficiencies. Van Allen et al. [Am J Med Genet 1987;28:529-548] proposed that the diagnosis of LBWC (presence of body wall defects with evisceration of thoracic and/or abdominal organs, limb deficiency, and myelocystocele) should be based on the presence of two of three of the following anomalies: exencephaly or encephalocele with facial clefts, thoraco and/or abdominoschisis, and limb defects. This approach implies that an infant with encephalocele with facial clefts and limb defects may be considered as having LBWC, which I do not think is correct. I present the results of a clinical and epidemiological analysis aimed at identifying if, from an epidemiological perspective, it is possible to identify an entity which is characterized by the presence of abdominal wall defects along with other malformations including or not limb deficiencies. The result of this analysis allows us to consider that this entity should be characterized by the presence of abdominal wall defects with a variable spectrum of anomalies (with or without limb deficiencies) and, consequently, be called body wall complex (BWC). BWC includes cases regardless of their clinical pattern and the possible etiology or pathogenetic mechanism. Thus, the BWC entity does not include amniotic band sequence without body wall defects, but does include amniotic band sequence with body wall defects.

Epidemiological characteristics of amniotic band sequence (ABS) and body wall complex (BWC): are they two different entities?

In 1965, Torpin [1965; Am J Obstet Gynecol 91:65-75] concluded that fetal constrictions and amputations were related to amniotic membrane rupture. Since then, this view was accepted widely, although different terms were used due to the variation in the types of associated anomalies. I consider that for those cases without body wall defects, the most appropriate term is amniotic band sequence (ABS), since amnion rupture could initiate a cascade of abnormalities (consequences) leading to the final structural defects. Here I present a clinical and epidemiological analysis of a series of consecutive infants with ABS, comparing their characteristics with those of infants with body wall complex (BWC). The results of this analysis suggest that ABS, from an epidemiological standpoint, is an entity different from BWC, and that amniotic bands in cases of BWC may be considered different from amniotic bands in cases without body wall defects. The former are probably produced earlier in the development than the latter.

Umbilical cord agenesis in limb body wall defect

The term "Limb Body Wall Defect" (LBWD) refers to a variable group of congenital defects having in common abdomino- or thoraco-schisis and limb deficiency. Three general pathogenic mechanisms have been proposed for this disorder: amnion rupture, vascular disruption, and embryonic malformation. We hypothesize that there are subsets of "Limb Body Wall Defect," which have similar structural abnormalities and a common pathogenesis. We report on five cases of LBWD that were selected by using more restrictive criteria. An infant or fetus was included if it had abdominoschisis with a broad attachment of skin to amnion at the site of the abdominal wall defect, limb defects, and umbilical cord agenesis. Autopsy detected additional common structural defects. All had evisceration of the gastrointestinal structures into the extra-embryonic coelomic space with structural abnormalities of the intestines. All had scoliosis, thoracic deformities, pulmonary hypoplasia, and structural abnormalities of the cloaca and urogenital ridge. Four of five had meningomyelocele. Three had exstrophy of the cloaca. The four females all had ovarian agenesis and incomplete Mullerian fusion. None had normal development of the external genitalia. We propose that the pathogenesis was a primary malformation of body wall closure, with abnormal fusion of the amnion, which had occurred in the first month of development.

Limb body wall complex: a critical review and a nosological proposal

The analysis of the literature on limb body wall complex reveals a varied and rather confused spectrum of cases. However, we noticed the presence of at least 2 clearly distinguishable phenotypes. The first phenotype shows craniofacial defects and amniotic bands and/or adhesion; the second--without craniofacial defects--presents urogenital anomalies, anal atresia, and abdominal placental attachment, together with a persistence of the extra-embryonic coelom. We think these 2 phenotypes are the consequence of different pathogenetic mechanisms. The pathogenesis of the first type can be related to an early vascular disruption, while the pathogenesis of the second one is attributable to an intrinsic embryonal maldevelopment. Eight cases of the second phenotype were identified and the pathological findings proving this maldevelopmental origin are described.

Amniotic band syndrome: a population-based study in two Australian states

A search for cases of amniotic band syndrome was made in two population-based Australian birth defects registries, using defined selection criteria. Over a period of 4 years in Western Australia and 5 years in South Australia, 25 cases of amniotic band syndrome had been identified as such by the two registries, and an additional 15 new cases were identified by the study selection process, giving an annual prevalence of amniotic band syndrome over the study period of 2.03 per 10,000 births. Similar proportions of male and female infants were affected, although the syndrome was more common in mothers younger than 25 years of age, and in first births. Limb defects only (upper and/or lower) were found in 24 cases, limb-body-wall defects in four cases, and complex craniofacial and other malformations in 12 cases. A heightened awareness of the syndrome should enhance the identification of amniotic band syndrome, which has implications for genetic counselling, and our understanding of the aetiology and pathogenesis of this condition.

Amniotic band sequence and limb defects: data from a population-based study

Cases with amniotic bands were analysed separately as part of an ongoing study of limb defects occurring among 1,213,913 liveborn infants in British Columbia during the years 1952 to 1984. A total of 24 cases with this specific condition was identified among 659 cases with limb defects. The calculated incidence for amniotic band sequence with significant limb involvement was 0.19 in 10,000 livebirths. This is a minimal incidence, as cases without defects of the limbs, but with constriction rings were not identified with this approach. Familial cases and cases with additional anomalies were found.

Anencephaly and limb deficiencies

Limb deficiencies (LDs) are rarely reported in anencephalic infants. A review of 662 patients in the literature on non-neural defects in anencephaly only showed five patients with LDs. We report on eight patients with various LDs from the records of 141 necropsies of the anencephalic infants found among 495,830 births. Compared with another group of anencephalic infants reported in the literature, the patients in this group of anencephalic infants with LDs were predominantly male, their mean gestational age was younger by approximately 5 weeks, their mean birth-weight was approximately 1,400 g less, and they presented with a higher incidence of polyhydramnios during gestational development. The association of this pair of anomalies, which was 100 times more frequent than expected, seems not due to chance. Since all eight patients had other multiple congenital anomalies (MCA), in addition to anencephaly and LDs, the postmortem study should be mandatory in anencephalic infants with LDs. The most common associated anomalies were cardiovascular and renal defects. Oral clefts, diaphragmatic hernia, esophageal atresia, and imperforate anus were also observed in these infants. The recognition of LDs in anencephalic infants indicates severe and extensive disturbance of the early embryogenesis (blastogenesis), which affects the midline of the embryo.

Structural anomalies resulting from vascular disruption

A diverse yet distinctive group of disorders and structural anomalies result from vascular disruption of embryonic and fetal blood vessels. The extent of damage, timing in gestation, and the mechanism of vascular disruption all determine the nature of the resultant structural anomalies. The developing human remains susceptible throughout pregnancy to teratogenic agents and events that alter uterine, placental, and embryonic or fetal circulation.

Constrictive amniotic bands, amniotic adhesions, and limb-body wall complex: discrete disruption sequences with pathogenetic overlap

In a fetopathologic evaluation of 18 cases with amniotic bands, we discerned 3 types of lesions: (1) constrictive tissue bands, (2) amniotic adhesions, and (3) more complex anomaly patterns, designated as limb-body wall complex (LBWC). Constrictive bands are caused by primary amnion rupture with subsequent entanglement of fetal parts (mostly limbs) by shriveled amniotic strands. Adhesive bands are the result of a broad fusion between disrupted fetal parts (mostly cephalic) and an intact amniotic membrane. Most of the craniofacial defects (encephaloceles and/or facial clefts) occurring in these fetuses are not caused by constrictive amniotic bands, but are the result of a vascular disruption sequence with or without cephalo-amniotic adhesion. Our observations confirm the fact that amnion rupture is not a conditio sine qua non for the development of LBWC. However, LBWC is often complicated by rupture of the unsupported amnion with ensuing formation of constrictive bands. We think that the concept that considers the 3 lesions in question as a single pathogenetic entity is erroneous and will inevitably lead to a never-ending debate between followers of the 2 prevailing theories. In our view, the theories of Streeter and Torpin are not mutually exclusive but rather apply to different types of lesions. The recognition of constrictive amniotic bands, amniotic adhesions, and LBWC as discrete but often combined disruption sequences with important pathogenetic overlap may resolve many dilemmas in interpretation when a fetus exhibits classical constrictive bands beside more severe defects.

ADAM sequence and innocent amniotic band: manifestations of early amnion rupture

Thirteen placentas with early amnion rupture (EAR) are described. These placentas were characterized by the absence of amniotic epithelium on the fetal surface, presence of a slightly fibrotic small amniotic band (remnant) attaching to the umbilical cord at the placental end, and the presence of degenerated vernix squamous cells in the fibrous stroma of chorion and amnion. Eight fetuses had ADAM sequence. Six of these fetuses were miscarried between 16 and 28 weeks of gestation. Two affected infants were born alive at gestational ages of 29 and 39 weeks. Five infants were spared by ADAM sequence; two had the umbilical cord strangulated by an amniotic band and were delivered at 27 and 37 weeks. In the 3 infants unassociated with ADAM sequence or strangulation of the umbilical cord, their placentas were interpreted as having innocent amniotic band (IAB) and they were delivered between 32 and 40 weeks. The findings in this study support Torpin's hypothesis that ADAM sequence is a complication of EAR. This ADAM sequence due to simple EAR must be separated from the limb body wall malformation complex because visceral anomalies are uncommon in the former condition but are frequently seen in the latter. In this study the placental pathology of EAR was helpful in confirming the ADAM sequence in the fetus.

Fetal disruptions: assessment of frequency, heterogeneity, and embryologic mechanisms in a population referred to a community-based stillbirth assessment program

The Wisconsin Stillbirth Service Project (WiSSP) is a community-based program for the investigation of the cause of fetal death. From its inception in 1983 through July 1988, 629 referrals were made to WiSSP. All referrals were assessed for the presence of disruptional characteristics, and 23 were found to have major or primary disruptive effects. Most of these were either early amnion disruption/limb-body wall disruption (treated as a single group, since analysis suggests a continuum of clinical characteristics) and twin-twin disruptions. Therefore, disruptions accounted for 3.6% of all referrals (including liveborn and miscarriage referrals) to WiSSP. When only stillborn fetuses are considered, approximately 2.4% appear to have died because of disruptions. This makes disruptions one of the most frequent, identifiable causes of late intrauterine death. We estimate that 0.6-1.4% of all stillborn fetuses die because of early amnion disruption/limb-body wall disruption which, when taken with previous estimates of the frequency of such problems in early miscarriages and liveborn infants, suggests that these disruptions result in a 95% prenatal mortality rate. We suggest a unified model of likely pathogenetic mechanisms which may help explain the continuum of multisystem involvement seen in those with early amnion disruption/limb body wall disruption. In addition, 3 patients with atypical disruptions are reviewed who exemplify the difficulty and importance of differentiating disruptional and malformational processes.