Children's Hospital Colorado

Amniotic Band Syndrome

Amniotic band syndrome (ABS) occurs when the amnion, one of two layers that form the amniotic sac, tears or is damaged. This may cause bands to form, which can attach and tighten around any part of a developing baby, including the umbilical cord. These amniotic bands can disrupt development and put the baby at risk.

Amniotic Band Medical Illustration

The Colorado Fetal Care Center is here for moms and babies experiencing difficulties related to amniotic band syndrome. We know that early diagnosis and quick treatment are the best ways to prevent complications from ABS. That's why our team of multidisciplinary fetal specialists are here to support you and your family.

Learning that your baby has amniotic band constriction can be overwhelming. But the Colorado Fetal Care Center is a national leader in diagnosing and treating this syndrome. We'll be with you every step of the way.

For patients

Amniotic band syndrome, or ABS, refers to conditions caused by damage to the amnion, the sac surrounding a fetus in utero. When this sac is partially disrupted, fibrous strings or bands can enter the amniotic fluid and wrap around parts of a baby's body, hindering growth.

In most cases, amniotic bands wrap around the arms, legs or fingers and toes. Some rare cases involve the head or waist of a baby. The disruption in the amnion can occur anytime between 6 and 18 weeks of pregnancy. The earlier the bands form, the more likely it is for these bands to result in serious complications.

What causes amniotic band syndrome?

Current studies estimate that ABS occurs in approximately 1 out of every 1,200 live births. This syndrome is caused by fibrous strands or bands entering the uterus and wrapping around parts of a baby's body. As the baby grows, the bands tighten and constrict growth and blood flow. The bands usually enter the uterus due to a partial rupture of amnion, the sac surrounding the baby.

There is no increased risk of this condition happening again in a future pregnancy.

The signs of ABS vary depending on when the damage to the amniotic sac occurs, as well as which of the baby's body parts are constricted by the amniotic bands.

What are the complications of ABS?

Amniotic bands, when wrapped around your baby's body parts, can cause limb deformities such as:

  • Clubfoot
  • Stunted growth of fingers and toes
  • Webbed toes or fingers
  • Cleft palate

In the most severe cases, amniotic bands cause organ damage or loss of pregnancy.

What is the long-term outcome for babies with amniotic band syndrome?

The outcome depends on many variables, including:

  • Timing of the amnion's rupture during pregnancy
  • Location of the band constriction
  • If and when the condition is diagnosed (usually through an ultrasound or at birth)
  • The severity of the damage caused by band constriction

All cases of amniotic band syndrome have PPOROM (Preterm Premature Rupture of Membranes) and the average gestational age delivery is 32 weeks.

But there is good news! Early diagnosis at specialist clinics like the Colorado Fetal Care Center can potentially save a baby's life or limbs.

How is ABS diagnosed in utero?

Most amniotic bands are found during routine ultrasound between 6 and 18 weeks of pregnancy. However, if a band is visualized on ultrasound, it does not automatically mean that your baby has suffered damage.

If ABS is diagnosed, the team at the Colorado Fetal Care Center gets to work creating a care plan tailored to your baby's specific case. Sometimes, prenatal surgery is recommended to prevent or decrease complications from amniotic bands. In cases of ABS that do not threaten life or limb, postnatal surgery might minimize or reverse the effects of birth defects once a baby is born.

The Colorado Fetal Care Center tailors the treatment of amniotic band syndrome to your child's specific needs. Amniotic band syndrome is often treated after birth with surgery to repair defects, but sometimes fetal surgery may be required.

Fetoscopic surgery

When an amniotic band endangers a baby's life by constricting growth of critical internal organs or threatening the umbilical cord, our specialized surgeons perform an in utero procedure to free the baby from the bands. Additionally, fetal surgery for ABS can save a limb if the baby is at risk of losing it.

Surgery after birth

When babies are born with birth defects caused by band constriction, surgeons can perform reconstructive surgeries to repair cleft palates or cleft lips, webbed feet or fingers or other body parts damaged by constrictive bands.

Why choose the Colorado Fetal Care Center to treat your baby's ABS?

The Colorado Fetal Care Center is one of the nation's top care centers for the treatment of amniotic band syndrome. We have successfully performed surgeries on babies ranging from 16 to 27 weeks' gestation and have a committed fetal surgery team with many years' experience providing care for expectant families.

For healthcare professionals

Amniotic band syndrome is associated with numerous antenatal sonographic features, as there are numerous forms of the syndrome and these features may occur as isolated problems or in combination. The earliest that amniotic bands have been seen is at 12 weeks of gestation by an endovaginal probe. The bands can be extremely difficult to detect sonographically and amniotic band syndrome is more often diagnosed by the effect that they have on fetal anatomy. The effect of amniotic bands on the extremities may be manifested by absent digits or portions of limbs or a swollen distal arm or leg resulting from constrictive amniotic bands (Paladini et al., 2004). ABS may affect the face with cleft lip or palate, asymmetric microphthalmia or severe nasal deformity. Encephalocele may be a manifestation of ABS especially when eccentrically placed.

Abdominal wall defects can be the result of ABS, typically with large defects with free-floating intestine herniated outside the abdomen. The characteristic appearance of an aberrant sheet or band of amnion attached to the fetus with resultant deformity and restriction of motion allows a diagnosis of ABS to be made. However, prenatal diagnosis is the exception rather than the rule.

Sonographic image of a 20 week fetus with a constricting amniotic band of the upper extremity.

Sonographic image of a 20-week fetus with a constricting amniotic band of the upper extremity.

The findings in ABS may be limited to isolated defects, including isolated facial cleft, digital amputation or mild elephantiasis of an extremity beyond a constrictive band (Sentilhes et al., 2004; Dyson et al., 2000). These isolated features may be difficult to diagnose sonographically because the detailed fetal visualization required is beyond the scope of routine obstetrical ultrasound examinations. At the worst end of the spectrum, the fetus may be so severely deformed by the amniotic bands that the spine is contracted and organs are formed in perplexing and bizarre proportions. The head may be completely misshapen or absent. The bands responsible for these deformities are rarely seen and a presumptive diagnosis of ABS is made based on the commonly associated deformities.

A 3-D image of a fetus showing a constricting amniotic band of the upper extremity.

A 3-D image of the same fetus showing a constricting amniotic band of the upper extremity.

The spinal deformities in ABS can be severe, manifesting as kyphotic lordosis or scoliosis as well as severe rotational abnormalities and even spinal amputation (Chen, 2001). While spinal deformity can be seen in other syndromes, severe spinal deformity should suggest ABS.

Spinal deformity associated with an abdominal-wall defect is particularly suggestive of ABS. While the typical appearance of an omphalocele is possible, the more common defect is a large slash-like defect of both the thoracic and abdominal cavities with evisceration. These defects are associated with exteriorized bowel, liver and sometimes heart without an enveloping membrane. When associated with limb abnormalities, this is characteristic of the limb-body-wall complex form of ABS.

Sonographic image demonstrating an amniotic band floating in amniotic fluid.

Sonographic image demonstrating an amniotic band floating in amniotic fluid.

Deformation of the calvarium is another group of anomalies characteristic of ABS. If complete, the fetus may appear to be anencephalic or to have acrania (Chen et al., 2004). If partial, the fetus may appear to have an encephalocele. The distinguishing features that characterize these defects as ABS are their asymmetric nature and associated spinal deformity or abdominal wall defects. In classic anencephaly, the calvarial bones are symmetrically absent. In anencephaly caused by ABS, there is some portion of calvarium present, usually near the base of the skull or near one other orbit. Similarly, classic encephaloceles occur near the midline while ABS causes encephaloceles off the midline.

The presence of bands is unnecessary for the diagnosis of ABS in the presence of characteristic fetal anomalies. The sonographic detection of bands is helpful in confirming the diagnosis of ABS as the cause of fetal deformity. However, observation of these bands without fetal abnormality is not ABS. It is important for the sonographer to distinguish amniotic bands from other membranes and separations within the amnion. Separation of amnion and chorion is normal in early pregnancy until fusion occurs at approximately 16 weeks of gestation (Burrows et al., 1982; Patten et al., 1986; Sauerbrei et al., 1980).

Chorioamniotic separation may occur as a result of amniocentesis or fetal surgery and extra chorionic hemorrhage may separate the chorioamniotic membrane from the uterine wall (Burrows et al., 1982; Graf et al., 1997; Spirit et al., 1979). In both of these instances, a membrane may be observed sonographically. Other causes of membranes in the developing fetus include the septate uterus, blighted twin and circumvallate placenta (Filly et al., 1991).

Adhesions that form in the uterus as a result of curettage, cesarean section or myomectomy may cause sheets of amnion that protrude into the lumen of the amniotic cavity (Asherman, 1948; Comninos et al., 1969; Filly et al., 1991; Mahony et al., 1985; Randal et al., 1988). Randal et al. (1988) found that 76% of patients with amniotic sheets had undergone prior instrumentation. This results in an adhesion that becomes covered by chorion and amnion and has a thickness similar to the intertwin membrane of dichorionic diamniotic twins. These amniotic sheets do not adhere to the fetus because the amnion is intact (Tan et al., 2005). The uterine adhesion may rupture with the growth of the fetus. Filly et al. (1991) have described the sonographic appearance of these synechiae as having a thickened base and a fine edge that undulates. There may be a bulbous edge, presumably due to the synechiae. There are no associated fetal abnormalities and there is free fetal movement around the sheet. The synechiae may not be seen in the third trimester, whether due to rupture or compression by the growing fetus.

In the limb-body-wall complex, there is a constellation of abnormalities including myelomeningoceles or caudal regression, thoraco-abdominoschisis or abdominoschisis and limb defects. At least two of the three abnormalities listed above are necessary to make a diagnosis of LBWC. The umbilical cord is usually short or absent with the placenta attached to the fetus. If present, there may be only a two-vessel cord. The limbs may be missing or the feet clubbed. The spine is often short and curved and sacral regression is common. There may be Arnold-Chiari malformation and hydrocephalus associated with the meningomyelocele. There may be ectopia cordis as part of the thoraco-abdominoschisis. Facial clefts may also be seen in LBWC.

ABS involving the umbilical cord can be recognized by abnormal clustering of loops of the umbilical cord which may be adherent to a bend fixed to a limb. These findings may be subtle and should be sought in any case of ABS as umbilical cord involvement may result in fetal demise.

There is great controversy about the pathogenesis of the various forms of amniotic band syndrome. Part of this controversy involves the timing in gestation of the development of amniotic bands. However, in constrictive amniotic bands of the extremities, the progression of constriction combined with fetal growth has resulted in extremity amputation (Hill et al., 1988). ABS can be associated with either polyhydramnios or oligohydramnios. Despite the severity of some forms of ABS, there are no adverse maternal consequences for this diagnosis. The incidence of intrauterine fetal death from ABS involving the umbilical cord is not known but numerous cases have been reported (Graf et al., 1997; Kanayama et al., 1995; Torpin, 1965). However, the poorly characterized pathogenesis of this syndrome and limited sonographic surveillance limit our understanding of its prenatal natural history.

ABS is a relatively common, if underappreciated, cause of fetal and neonatal morbidity and mortality. The fetal-lamb model of ABS will be useful to better define the pathophysiology of ABS and to provide a tool to understand the unique fetal response to tissue injury, repair and regeneration. Sonographic identification of ABS affecting the umbilical cord may be an indication for fetoscopic surgical intervention. In the future, intervention for nonlethal limb deformation may also be considered if maternal risk is sufficiently lowered. ABS is another in a growing list of conditions for which fetal surgery may be considered in the future.

Constrictive bands most commonly affect the extremities but can also involve the umbilical cord with resulting fetal death. Kanayama et al. (1995) described the reversal of diastolic flow observed in a fetus with umbilical-cord constriction due to amniotic bands. Graf et al. (1997) similarly reported a case of amniotic bands involving the umbilical cord following the development of chorioamniotic separation. Despite initially normal umbilical artery Doppler waveforms, this fetus died within 2 weeks from a constrictive amniotic band of the umbilical cord. Reports have described constrictive amniotic bands as a cause of fetal death (Moerman et al., 1992; Torpin, 1965). However, until the reports by Kanayama and Graf and their colleagues, this was a diagnosis made pathologically after the fact. It is in cases like these that fetoscopic lysis of amniotic bands could be lifesaving (see Fetal Intervention).

Cases of ABS, by definition, have ruptured membranes and typically deliver prematurely with an average gestational age of 32 weeks’ gestation.

Several theories have been advanced to explain the occurrence of these anomalies but two are most commonly held. In 1930, Streeter proposed that a disruption in embryogenesis at the time of formation of the germ disk and the amniotic cavity initiated a chain of events leading to the multiple defects. He suggested that amniotic bands were the result, not the cause, of the pathologic process. In 1992, Bamforth reviewed this theory in a series of 54 cases of ABS and concluded that it may be caused by a localized disturbance in establishment of basic embryonic organization. The most widely accepted theory was proposed by Torpin in 1965. He examined the placenta and fetal membranes in a number of affected individuals and concluded that the disorder was caused by primary rupture of the amnion early in gestation (Herva et al., 1984; Higginbottom et al., 1979; Keller et al., 1978; Seeds et al., 1982).

More recently, Moerman et al. (1992) proposed that the ABS is a collection of three distinct entities that can reconcile the adherents of Streeter’s and Torpin’s hypotheses. They suggested that ABS consists of three distinct lesions: (1) constrictive tissue bands; (2) amniotic adhesions; and (3) the more complex pattern of anomalies designated the limb-body-wall complex (LBWC). In this report of the fetopathologic evaluation of 18 cases of ABS, 4 had clearly constrictive bands which formed as a result of the amnion rupture sequence. The bands that resulted from amnion rupture encircled the limbs, resulting in annular constrictions, secondary syndactyly and intrauterine amputations. In addition, constriction of the umbilical cord is a recognized cause of fetal death (Hong et al., 1963; Torpin, 1965). These authors distinguish cases caused by constrictive bands from those caused by broad amniotic adhesions. Moerman et al. suggested that adhesive amniotic bands were morphologically and pathogenetically different from constrictive bands. Adhesive amniotic bands are usually associated with severe defects such as encephalocele and facial clefts. This group demonstrated pathologically that cranioplacental adhesions are broad adhesions with the fetal skin fused to the amnion at the margins of the cranial defect. They speculated that the amnion covering the placenta or membranes seals the cranial defect separating the protruding brain from the chorion. Van Allen et al. (1987) proposed that the amnion becomes adherent to the embryo in areas of ischemic necrosis following vascular disruption. In short, the amniotic adhesions are secondary to fetal defects.

Moerman et al. (1992) considered the LBWC to be due to both band-related and non-band-related defects. The band-related defects include limb defects such as club foot. Non-band-related defects occur as a result of vascular disruptions or from compression (Miller et al., 1981). The thoraco-abdominoschisis of LBWC is characterized by an anterolateral body-wall defect with evisceration of abdominal and/or thoracic organs. The eviscerated organs are in an extraamniotic sac bounded by the chorionic plate, a persistent extraembryonic coelom. The amnion is continuous with the skin. The umbilical cord is extremely short with umbilical vessels running in the amniotic sac, often with an absent umbilical artery. The severe scoliosis is a postural deformity caused by abnormal fixation of the fetus to the placenta. They also cite the high incidence of internal structural defects such as cardiac anomalies, unilateral absence of a kidney or intestinal atresia which do not fit with simple amnion rupture.

The fetal malformations that can occur as a result of ABS can be categorized into neural-tube–like defects, craniofacial anomalies, limb anomalies and constrictive bands (Ho and Liu, 1987; Lubinsky et al., 1983; Seeds et al., 1982; Seidman et al., 1989). The neural-tube-like defects include cases of anencephaly and encephalocele which may be asymmetric or multiple. The craniofacial anomalies include facial clefts, nasal deformity, asymmetric microphthalmia and abnormal cranial calcification. Limb anomalies may be multiple and asymmetric, including limb or digital amputation, pseudosyndactyly, abnormal dermatoglyphics and some cases of clubbed feet. Abdominal wall and thoracic wall defects can occur and some cases are mistaken for gastroschisis or omphalocele with rupture.

The most puzzling component of ABS is its association with visceral anomalies, including bladder exstrophy, vertebral hypoplasia and other renal, gonadal, cardiac and pulmonary defects (Bamforth, 1992). Constrictive bands involving the extremities are the most common defect associated with ABS (Huang et al., 1995).

The variation in manifestations of ABS are thought to be due to differences in timing of amniotic rupture and the degree to which the fetus becomes entangled by strands of amnion (Higginbottom et al., 1979; Seeds et al., 1982). The effects the amniotic bands have on the developing fetus have been classified into malformation, disruption and deformation (Higginbottom et al., 1979). Amniotic bands that interrupt the normal sequence of embryologic development lead to malformations such as cleft lip and palate and abdominal-wall defects. In contrast, bands may tear normally developed structures, leading to disruption such as central nervous system or calvarial defects, acrosyndactyly, amputations and nonanatomical facial clefts (Lockwood et al., 1989). The effects of fetal compression and tethering may lead to deformations such as clubbing of the feet and angulation of the spine.

The timing of amnion rupture has been suggested to occur between 28 days after conception to 18 weeks of gestation. If amnion rupture occurs prior to 45 days of gestation, the results are likely to be devastating, including severe skull defects and major visceral defects (Huang et al., 1995). Rupture occurring after 45 days of gestation is likely to result in more limited defects.

The cause of amnion rupture and band formation is not well understood, but it has been observed following amniocentesis (Rehder, 1978). Late gestation bands, even in the absence of an amniocentesis, can also occur. Lage et al. (1988) reported ABS presenting at birth with multiple abnormalities of the extremities despite a normal sonographic appearance at 21 weeks of gestation. There have also been cases of ABS associated with underlying disease. Young et al. (1985) reported two cases in fetuses with Ehlers–Danlos syndrome type IV and one with osteogenesis imperfecta. They speculated that the premature amnion rupture may have been due to reduced or abnormal collagen in the amnion. There have been rare familial cases of ABS and some teratogens, such as lysergic acid diethylamide and methadone, have been reported in association with the syndrome (Chemke et al., 1973; Daly et al., 1996; Lubinsky et al., 1983).

Chorioamniotic separation occurring spontaneously or as a consequence of invasive procedures is a potential cause of amniotic band syndrome. The incidence of chorioamniotic separation diagnosed by ultrasound is reported to range from 1 in 187 to 1 in 4,333 births (Borlum, 1989; Kaufman et al., 1985). The natural history of chorioamniotic separation occurring in normal pregnancies was initially thought to be benign. However, Graf et al. (1997) reported a case of chorioamniotic separation that resulted in the formation of amniotic bands involving the umbilical cord, resulting in fetal death. The incidence of chorioamniotic separation may be even higher in cases of fetal surgery. In the same report Graf and colleagues described 5 cases of chorioamniotic separation occurring in a series of 40 patients undergoing open fetal surgery. Three of the 5 fetuses had amniotic bands involving the umbilical cord, leading to fetal death in 1. This report speculated that because the amnion is adherent and fixed to the umbilical cord, once formed amniotic bands may retract to the cord, causing strangulation. Heifetz (1984), in a review of amniotic band syndrome, reported that as many as 10% of cases had umbilical-cord strangulation.

ABS is often misdiagnosed, especially in cases of early amniotic band rupture. Infants affected by early amniotic rupture present with anencephaly, encephalocele, abdominal or thoracic wall defects and severe limb abnormalities. The severity of the anomalies obscures the cause, especially if the amniotic bands are not evident at birth. It has been estimated that a correct neonatal diagnosis of ABS is made in only 24 to 50% of patients without specialized genetic consultation (Seeds et al., 1982).

Regarding fetal treatment for amniotic band syndrome, the indications for fetal surgery are, with few exceptions, only for life-threatening conditions such as congenital pulmonary airway malformation (CPAM) with hydrops, congenital diaphragmatic hernia (CDH) with a low lung: heart ratio, bladder-outlet obstruction with oligohydramnios or sacrococcygeal teratoma with placentomegaly. However, as experience with the techniques of fetal surgery has grown and the natural histories of certain non-life-threatening conditions have been better defined, the indications for fetal surgery have been extended. Two examples of this are in utero repair of meningomyelocele to prevent the devastating neurologic injury to the spinal cord (Adzick et al., 1998) and fetoscopic cord ligation in monochorionic twins with the imminent death of one twin to prevent neurologic injury in the surviving twin (Crombleholme et al., 1996). The indications for fetal surgery in the amniotic band syndrome may be either for a life-threatening condition if it involves constriction of the umbilical cord, or more commonly, threatened limb amputation due to amniotic band constriction (Keswani et al., 2003; Crombleholme, 2001; Ashkenazy et al., 1982; Kanayama et al., 1995; Tadmor et al., 1997; Torpin, 1965).

Torpin (1965) reported 36 cases of fetal death due to cord constriction from amniotic bands. In each case, the diagnosis was made retrospectively, however. Recognition of amniotic bands constricting the umbilical cord has been reported by Kanayama et al. (1995), who were able to document fetal compromise by reversal of diastolic flow in the umbilical artery by color Doppler. It is in cases like the one reported by Kanayama et al. that fetoscopic lysis of amniotic bands could be lifesaving.

Based on their experience with fetoscopy for cord ligation in TRAP sequence and the experimental work by Crombleholme et al. demonstrating the potential for functional recovery of banded extremities once released, Quintero et al. performed the first fetoscopic lysis of amniotic bands in human fetuses (Crombleholme et al., 1995; Quintero et al., 1997). Their first case was a fetus at 21 weeks of gestation with bilateral cleft lip and bands attached to the face and left upper extremity with distal limb edema. In order to avert limb amputation, fetoscopic lysis of bands was attempted at 22 weeks of gestation using a two-port technique. However, due to bleeding encountered on insertion of the second operating port, it was removed. The endoscissors were passed through the port used for the fetoscope and the lysis was performed under ultrasound guidance. There was resolution of the distal edema within 6 days of the procedure. At 32 weeks, microphthalmia and anophthalmia of the right orbit were first noted at the site of the previously attached amniotic band. The infant was delivered at 39 weeks and was found to have a type IV Tessier craniofacial cleft and right microphthalmia. The extremity showed minimal residual scarring where the band had been attached and lysed. The infant’s hand had radial paresis and mild hypoplasia.

The second case was a fetus at 23 weeks of gestation with a thick amniotic band constricting the left ankle of the fetus. There was marked edema distal to the band and minimal blood flow to the foot was observed by color and pulsed Doppler. Fetoscopy was performed using a 2.7mm 5-degree endoscope and confirmed the sonographic findings. Again, bleeding was encountered on insertion of the operating port, necessitating its removal. Attempts at ultrasound-guided lysis using endoscissors were unsuccessful. A 2.4mm 0-degree operating scope with a 400-µm contact YAG laser fiber was used to lyse approximately 85% of the band. Complete lysis of the band was not achieved for fear of injury to “important elements in the ankle.” Postoperatively, the edema markedly improved, as did distal arterial blood flow, and there was return of flexion and extension on follow-up sonographic examination. The mother was hospitalized 8 weeks postoperatively at 31 weeks of gestation with premature rupture of membranes and delivered at 34.5 weeks of gestation. The infant underwent Z-plasties for residual effects of the amniotic band and full functional recovery was anticipated.

The rationale for performing fetoscopic lysis of constricting extremity amniotic bands is based on the hypothesis that progressive compromise of fetal growth leads to amputation. However, this assumes that the procedure can be accomplished with no maternal morbidity and minimal fetal morbidity. This procedure would be hard to justify in the face of a serious maternal complication or a fetal death due to severely premature delivery at 21 or 23 weeks of gestation, even in the face of certain fetal limb amputation.

The experience reported by Keswani et al. (2003) similarly supports the use of fetoscopic release of amniotic bands for limb salvage. However, the sequelae of the ABS may not completely remove or may result in secondary lymphedema. It is worth noting that the cases reported all had additional amniotic bands encircling limbs not appreciated by ultrasound which were also lysed. Crombleholme has experience with fetoscopic release of amniotic bands involving the umbilical cords in 3 fetuses (Crombleholme, unpublished observation, 2008). All were successfully lysed with all 3 surviving.

While extremity ABS may have devastating morphologic and functional effects on a limb, possibly resulting in amputation, it is not lethal. Extremity ABS is not an indication for fetoscopic surgery unless maternal risks and incidence of preterm labor are fully appreciated by the mother. However, there are forms of ABS that are lethal or have devastating neurologic sequelae that may justify the current risks of intervention. Torpin (1965) has reported 36 cases of constrictive amniotic bands of the umbilical cord which were uniformly fatal. Although rarer than other forms of ABS, umbilical-cord constriction, once diagnosed sonographically, may be amenable to fetoscopic release to avert fetal death as shown by Crombleholme (unpublished observation, 2008).

In managing a pregnancy with suspected amniotic band syndrome, it is essential to have a detailed sonographic fetal survey to accurately assess any anomalies present. Fetal echocardiography is indicated in cases of abdominal wall or abdominothoracic wall defects because of the increased incidence of associated cardiac defects. Amniocentesis is not necessary in clear-cut cases of ABS as these are sporadic deformations with no association with chromosomal abnormalities. However, in instances in which the diagnosis is uncertain, genetic amniocentesis should be considered. For example, in cases of abdominal wall defects in which a ruptured covered omphalocele cannot be excluded, genetic amniocentesis is indicated.

A fetus with ABS should pose no increased risk for the mother in the management of the pregnancy. There is no indication for cesarean section, except for obstetrical indications. In severe cases of ABS, such as LBWC, in which survival is not anticipated, conventional labor and vaginal delivery without intervention for fetal distress should be considered.

Amniotic band syndrome surgery usually begins after birth unless it's been deemed life threatening. A fetus known to have amniotic band syndrome should be delivered in a tertiary-care center with neonatologists, pediatric surgeons and pediatric plastic and orthopedic surgeons available. Treatment depends on the nature of the amniotic band syndrome and the severity of the deformation. In cases of umbilical-cord involvement, early or even emergency delivery may be indicated if there are signs of fetal compromise (Kanayama et al., 1995).

After delivery, a careful physical examination should assess the severity of the amniotic band syndrome. Often there will be no evidence of the amniotic band at the time of delivery. In the case of extremity amniotic bands, treatment is dictated by the severity of the deformation. The severity of deformity can range from a mildly constrictive band requiring a release to near amputation requiring debridement. More often there is a band-like deformation that requires Z-plasties to surgically correct (Findik et al., 2006; Dyer and Chamlin, 2005).

In cases of amniotic bands involving the face and head, there may be severe facial clefts, anophthalmia and encephalocele. These deformities may require many extensive reconstructive procedures to achieve an acceptable cosmetic result. Cases of the LBWC form of amniotic band syndrome are always fatal and no reconstructive procedures are indicated.

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