Amniotic Band Syndrome

Amniotic band syndrome (ABS) occurs when loose bands of tissue in the uterus entangle a developing fetus. The bands prevent blood from getting to the fetus’s body parts. ABS can lead to serious birth disorders or even death. Treatment usually includes surgery, prosthetics (artificial body parts) and rehabilitation.


What is amniotic band syndrome?

Amniotic band syndrome (ABS) occurs when loose bands of tissue in your uterus get wrapped around the fetus. The bands may tighten and prevent blood from reaching body parts, such as the legs and arms.

ABS can prevent body parts from developing normally, leading to birth defects (congenital disorders). Sometimes it causes body parts to amputate, or separate from the fetus. Amniotic bands can also cause a fetus to die in the uterus if blood can’t get to vital organs.

Another name for amniotic band syndrome is amniotic band sequence.


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What are the risk factors for amniotic band syndrome?

You may be more likely to have ABS if you:

How common is amniotic band syndrome?

ABS is rare. It occurs in about 1 out of every 1,200 to 15,000 live births.

Symptoms and Causes

What causes amniotic band syndrome?

There are two main theories about the cause of ABS. The amnion membrane (inner layer of the amniotic sac that holds the fetus in your uterus) becomes damaged. This causes bands of tissue from the amnion to come loose in your uterus. The bands may wrap around the body parts of a fetus. These bands can tighten and keep blood from getting to the fetus’s body parts, usually the arms or legs.

Causes of amniotic sac damage may include:

  • Drugs such as misoprostol, which providers use to end a pregnancy early.
  • Prenatal tests such as chorionic villus sampling (CVS) or amniocentesis. These tests puncture the amniotic sac with a needle to get a sample of fluid or tissue from the fetus. This complication has occurred but is exceptionally rare.
  • Open fetal surgery, which is reserved for serious, life-threatening fetal conditions only.

But in some cases of ABS, the amniotic sac remains intact and undamaged. So other experts believe ABS is the result of circulation (blood flow) problems in the fetus. It’s possible that some fetuses have an abnormal gene that makes them more likely to have circulation problems.


What are the signs of amniotic band syndrome?

Sometimes ABS is mild and only restricts blood flow to the surface of the skin. Most cases (about 80%) involve the hands or feet. However, the location of the band determines which area is affected. Deep blood flow constriction may lead to:

  • Constriction rings in the skin.
  • Missing fingers, toes or limbs.
  • Syndactyly (webbing or fusion between fingers or toes).
  • Shortened or underdeveloped limbs.
  • Bone deformities, including scoliosis.
  • Choanal atresia (underdeveloped nasal passage).
  • Clubfoot.
  • Microphthalmia (small or underdeveloped eyeballs).

The following complications of ABS can be life-threatening:

  • Encephalocele (openings in the skull).
  • Head and face deformities, such as cleft lip and palate.
  • Openings or defects in the abdomen or chest.
  • Underdeveloped lungs.
  • ABS often causes a premature birth which can have its own risks.

Diagnosis and Tests

How is amniotic band syndrome diagnosed?

A healthcare provider usually diagnoses ABS soon after birth. Sometimes a provider diagnoses ABS prenatally, when the fetus is still in your uterus. An ultrasound may reveal lines from the tightened bands of tissue. More often, the ultrasound shows missing limbs or body parts that aren’t developing correctly. Signs of ABS are usually visible as early as 12 weeks into a pregnancy.


Management and Treatment

How is amniotic band syndrome treated?

The affected body parts and functions determine the treatment for ABS. Mild cases of ABS may only need careful monitoring by a healthcare provider. But severe ABS that affects organ function needs immediate treatment.

Sometimes surgery can correct issues such as club foot, cleft lip and palate or webbing. Infants or children with missing or shortened limbs may benefit from prosthetics (artificial body parts). Physical therapy and occupational therapy can help them use the prosthetic and improve their overall function.

In rare cases, a healthcare provider may remove amniotic banding with surgery when the fetus is still in your uterus. This procedure carries serious health risks for the birthing parent and fetus. It’s usually only for constriction bands that threaten the fetus.

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How can I prevent amniotic band syndrome?

There’s no way to prevent amniotic band syndrome. But you can reduce your risk by staying as healthy as possible during your pregnancy.

Outlook / Prognosis

What is the outlook for amniotic band syndrome?

The outlook for babies with mild ABS is good. Children with congenital (present at birth) limb conditions typically adapt well to prosthetics and rehabilitation. Babies with severe brain, lung or other organ dysfunction usually don’t survive.

Living With

What should I do if my child has amniotic band syndrome?

Children with ABS will need a strong support system. Parents, family members and healthcare providers can help them as they adapt to the cosmetic and functional challenges of ABS. Families and older children may benefit from support groups for specific health issues.

A note from Cleveland Clinic

Amniotic band syndrome (ABS) is a condition where bands of tissue in your uterus wrap around a developing fetus and restrict blood flow. ABS can cause a variety of congenital disorders, ranging from missing limbs to underdeveloped organs. Treatment usually includes surgery, prosthetics and rehabilitation.

Medically Reviewed

Last reviewed on 10/21/2022.

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