Amniotic Band Syndrome occurs when the unborn baby (fetus) becomes entangled in fibrous string-like amniotic bands in the womb, restricting blood flow and affecting the baby’s development.
Amniotic Band Syndrome can cause a number of different birth defects depending on which body part(s) is affected. If a band wraps tightly around a limb, the limb can actually be completely amputated. The baby may be born missing fingers, toes, part of an arm or leg. If the band is across the baby’s face it can cause cleft lip and palate. In a large number of cases the baby is also born with clubfeet. ABS is also the cause of numerous miscarriages, such as when a band becomes wrapped around the umbilical cord.
ABS occurs randomly. It’s not genetic, nor is it caused by anything a pregnant Mom did or didn’t do during pregnancy. To date, no prenatal factors have been associated with ABS. It is extremely unlikely that ABS will affect a future pregnancy.
While babies are in the womb, a sac of fluid (amniotic sac) surrounds and protects them. In amniotic band syndrome, thin strands of tissue form inside this sac. The strands tangle around the baby, like strings or rubber bands, trapping parts of their body. Pressure from the strands can affect the way your baby forms.
As your baby grows, the strands make creases, or indentations, in their tissue. These creases are called amniotic bands. (They are also known as constriction bands or constriction rings.) Most bands affect only the outer layers of soft tissue, like the baby’s skin and the tissue just under their skin (subcutaneous tissue). Tighter bands may go as deep as the bone.
Bands happen most often around a baby’s arms or legs. Often, the bands go all the way around the limb. Some go only partway around (incomplete bands). Bands can also form around the head, face, chest or belly (abdomen). The exact effects depend on where the bands are and how early they began.
Amniotic Band Syndrome in Children
Amniotic band syndrome is rare, and the cause is not known.
No two cases of this syndrome are exactly alike. In the mildest cases, amniotic band syndrome causes a single, shallow crease on one limb. The crease can be seen, but it doesn’t cause problems with the way the limb works. Some children have multiple, deeper bands.
Bands that compress blood vessels may reduce blood flow to parts of your baby’s body. This may limit growth or injure tissue as the baby develops. Bands can be so tight that the tissue past them cannot survive because it doesn’t get enough blood. These bands may cut off fingers, toes or other parts of the arms or legs before a baby is born (congenital amputation or intrauterine amputation). If bands injure but do not amputate your baby’s fingers or toes, the digits may heal together in the womb and cause a type of syndactyly (acrosyndactyly). Sometimes the digits are fused only at the tips.
If bands compress nerves, they may cause other problems. A band around a nerve that controls the lower leg and foot (peroneal nerve) is one cause of clubfoot.
If bands cross your baby’s head, face, chest or abdomen, they may cause more serious problems with your baby’s development. Bands around the head or face may cause encephalocele or cleft lip and palate. Bands around the abdomen may cause problems with internal organs, like kidney problems or gastroschisis. Bands that cross the chest may cause heart defects.
This condition is known by many other names, including amniotic constriction bands, constriction band syndrome, congenital constriction rings, Streeter anomaly, Streeter bands and Streeter dysplasia.
Amniotic Band Syndrome at Seattle Children’s
Each baby with amniotic band syndrome needs a treatment plan tailored to them.
At Seattle Children’s we bring together experts from Orthopedics, Occupational Therapy, Orthotics and Prosthetics, Plastic Surgery, Neurosurgery, Craniofacial and other areas of healthcare as needed to care for your child. We work as a team to evaluate your baby and make a treatment plan that meets their needs.
Our surgeons are experienced at performing surgeries to release bands and correct the effects of bands on the way your baby formed.
The doctors at Seattle Children’s also provide prenatal consultations if an ultrasound before birth shows that your baby may have amniotic band syndrome.
The effects of amniotic band syndrome can vary widely. They depend on where the bands are and how early the bands formed during your baby’s development.
Your baby may have one or more of these:
- Creases, or indentations, around their finger, hand, arm, toe, foot or leg
- All or part of a limb missing
- Swelling (edema) because bands restrict the flow of blood or lymph
- A difference in the length of their arms or legs
- A gap (cleft) or other defect in their head, face, belly or chest
Doctors can diagnose amniotic band syndrome by doing a physical exam when your baby is born.
Your child may need an X-ray to see how a band affects deeper tissues under their skin. If a band is deep, your child may have an MRI (magnetic resonance imaging) scan or other imaging scan to see how the band affects their blood vessels and nerves.
Sometimes, but not usually, doctors can diagnose amniotic band syndrome based on what they see during an ultrasoundbefore a baby is born. If this happens, talk with your healthcare team about what they can tell from the ultrasound and what it may mean for you and your baby. Our team at Seattle Children’s is happy to provide prenatal consultations to talk with you about your baby’s condition.
What Causes Amniotic Band Syndrome?
Amniotic Band Syndrome is not genetic (i.e. not inherited). It is extremely unlikely that ABS will affect a future pregnancy. To date, no prenatal factors have been associated with ABS.
The commonly accepted view is that ABS occurs when the inner membrane (amnion) ruptures without injury to the outer membrane (chorion), this exposes the baby to fibrous sticky tissue (bands) from the ruptured amnion which can float in the waters of the uterus, these fibrous tissues can entangle the baby reducing blood supply and causing congenital abnormalities. In some cases a complete “natural” amputation of a digit(s) or limb may occur before birth or the digit(s) or limbs may be necrotic (dead) and require surgical amputation following birth.
A strong relationship between ABS and clubfoot exists. A 31.5% of associated clubfoot deformity and ABS can be correlated with 20% occurring bilaterally. Other abnormalities found with ABS include: clubhands, cleft lip, and/or cleft palate, and hemangioma.
Effects of Amniotic Band Syndrome
With Amniotic Banding no two cases are exactly alike. There are several features that are relatively consistent:
- syndactyly (webbed digits),
- distal ring constrictions,
- deformity of the nails,
- stunted growth of the small bones in the digits,
- limb length discrepancy,
- distal lymphedema (swelling), and
- congenital band indentations.
If a band wraps tightly around a limb, the limb can actually be completely amputated.
If the band is across the baby’s face it can cause cleft palate.
In a large number of cases the baby is also born with clubfeet.
ABS is also the cause of numerous miscarriages, such as when a band becomes wrapped around the umbilical cord.
In this photo of Evan’s hand you can see the banding line from his wrist to his pinky finger, he also has a banding line around the wrist. This photo is after two operations that separated his webbed fingers (syndactyly). His three fingers are small, with abnormal finger nails, and missing some joints, there is also some lymphedema (swelling at the joint) of the index finger middle joint. There is poor circulation in the ring finger as there were no major arteries in it at the time of surgery. Even on a hot July day, if you hold Evan’s hand you can feel how much colder this finger is then the rest of his hand.
Amniotic Band Syndrome – Alternative Names
Some of these are different names for ABS and some are other syndromes that are often confused with ABS. Misdiagnosis is apparently common.
- Amniotic Deformity, Adhesions and Mutilations
- Amniotic band disruption complex or sequence
- Amniotic bands and sheets
- Annular constriction bands
- Congenital ring constriction
- Constriction Band Syndrome and Amniotic Constriction Band Syndrome
- Intrauterine amputation
- Streeter’s dysplasia
- TEARS (The Early Amnion Rupture Spectrum)
- Congenital Transverse Defects or Deficiency
- Limb-body Wall Complex
Treatment depends on which body part the band was wrapped around and the severity of the abnormality it caused.
In Utero Surgery – has been performed to free limbs from amniotic bands that threaten to amputate limbs. Results of the first surgeries of this type were published in the “Journal of Ultrasound in Obstetrics & Gynecology.” It is the first minimally invasive treatment to correct a non-lethal fetal condition. Check out these links:
- Read Thomas’s Story
- Read Kai’s Story
- The Center for Fetal Diagnosis and Treatment
- Fetal Care Institute
Treating Syndactyly – Evan had two plastic surgeries to separate his webbed fingers. A great description of syndactyly and what surgery does can be found at HandWorld
Treatment of Congenital Amputation – The War Amps has a great program called Matching Mothers to connect families with similar amputations.
3D Printing of Prosthetics
Growing Hands -Distraction Augmentation Manoplasty – The technique pioneered by Dr. Cowen “grows” up to one inch of bone per month to create palms and lengthen fingers. A strange looking contraption of steel rods, pins, and screws is inserted through the existing bone. Screws are turned at an even rate several times a day to achieve growth of up to one millimeter a day. Turning the screws takes up slack and the body responds to this stress by growing bone.
Treating Cleft Lip and Palate
(U.S.) National Cleft & Craniofacial Awareness,
(Canadian Charity working in developing countries) Transforming Faces – Cleft Lip & Palate Surgery
- amnion rupture sequence
- amniotic bands
- amniotic band sequence
- amniotic deformity, adhesions, mutilations (ADAM) complex
- congenital constriction rings
- constriction band syndrome
- limb body wall complex
- Streeter anomaly
- Streeter bands
- Streeter dysplasia
- Disorder Subdivisions
Amniotic band syndrome is a well-known condition potentially associated with a variety of different birth defects. It is important to note that no two cases of amniotic band syndrome are exactly alike and that the associated symptoms are highly variable.
The severity of amniotic band syndrome can range from a single, isolated finding to multiple, disfiguring complications. The arms and legs are most often affected. The head and face and, in some cases, various internal organs can also be affected. The exact cause of amniotic band syndrome is unknown and controversial.
Two main theories have been proposed to explain the development of the disorder. One theory attributes the disorder to causes that arise internally within the fetus (intrinsic theory); the other theory attributes the disorder to causes acting upon the fetus externally (extrinsic theory). It is likely that both internal and external factors can cause amniotic band syndrome, and that the cause of the disorder in one infant may be different from the cause in another infant.
What is the outcome for a fetus with amniotic band syndrome?
The complications from the amniotic band syndrome can range from mild to severe. In mild cases, a band may become wrapped around digits (fingers or toes) of the fetus. This can result in amputations of the fingers or toes, or syndactyly of the fingers or toes. Syndactyly is a condition where the fingers or toes become fused together, or webbed, which can be treated surgically after birth. Amniotic bands attached to the face or neck can sometimes cause deformities such as cleft lip and palate.
In other instances, a band can be wrapped around a limb (arm or leg) resulting in restriction of movement leading to deformities such as clubbed foot. In more severe cases, an amniotic band can become tightly wound around a limb leading to decreased blood supply and resulting in possible amputation of the limb.
The most severe, and life-threatening complication of amniotic band syndrome is if a band becomes wrapped around vital areas such as the head or umbilical cord. Constriction to the umbilical cord or other vital areas can result in fetal death.
How serious is my fetus’s amniotic band syndrome?
Each case is unique, multiple strands may be entangled around the fetus, and the severity can range from mild to life-threatening depending on where the bands are constricting and how tightly they are wound.
If there is evidence of amniotic bands, a detailed ultrasound test should be done to assess the severity and avoid a misdiagnosis. Amniotic bands can be difficult to detect by ultrasound because of their small size, so it is important to have your case reviewed by someone knowledgeable in amniotic band syndrome. The individual strands are often hard to see on an ultrasound, and typically the condition is detected indirectly by the constrictions and swelling they cause to limbs and other parts of the fetal body.
What are my choices during this pregnancy?
Amniotic band syndrome causes no increased risk for the mother during pregnancy. Most complications of amniotic bands are handled after birth. For more severe cases, a detailed assessment of your situation is necessary before fetal surgery can be considered as an option.
In cases where the situation is mild, fetal surgery is not recommended and any complications will be treated after birth by reconstructive surgery. All cases of amniotic band syndrome should be monitored by ultrasound during pregnancy for potential increasing severity.
More severe cases may be considered for fetal surgery provided the maternal and fetal risks of surgery are small. A full evaluation is required before going ahead with fetal surgery as each case of amniotic band syndrome is unique and additional complications may be present. Fetal surgery may be a treatment option in select cases. This can be offered when the band is around a limb and causing swelling and obstructing blood flow to the limb. The fetal surgeons can enter the uterus with a small instrument and attempt to cut the band around the limb. This can be accomplished by either disrupting the band with a laser or cutting the band with a sharp instrument.
What will happen after birth?
A fetus with amniotic bands syndrome may require treatment after birth. Occasionally reconstructive surgery might be needed to correct deep constriction grooves, fused fingers or toes, cleft lip, or clubbed feet. Your child’s surgical needs will range from minor to complicated depending on the extent of the deformities caused by the amniotic bands.
In most situations, you will be able to discuss your options with a plastic surgeon shortly after birth. If you plan on delivering your child at UCSF Benioff Children’s Hospital, we have a very accomplished team of pediatric plastic surgeons who may be able to help.
Support Groups & Other Resources
Amniotic Band Syndrome Email Support Group — Email support group created for people that have been affected by Amniotic Band Syndrome both before and after birth, or for people born with ABS.
Amniotic Band Syndrome — Collection of stories written by families dealing with the complications of amniotic band syndrome.
March of Dimes — Researchers, volunteers, educators, outreach workers and advocates working together to give all babies a fighting chance
Birth Defect Research for Children — a parent networking service that connects families who have children with the same birth defects
Kids Health — doctor-approved health information about children from before birth through adolescence
CDC – Birth Defects — Dept. of Health & Human Services, Centers for Disease Control and Prevention
NIH – Office of Rare Diseases — National Inst. of Health – Office of Rare Diseases
North American Fetal Therapy Network — NAFTNet (the North American Fetal Therapy Network) is a voluntary association of medical centers in the United States and Canada with established expertise in fetal surgery and other forms of multidisciplinary care for complex disorders of the fetus.
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