What is Amniotic Band Syndrome?

Amniotic band syndrome, or ABS, happens with the lining of the amniotic sac gets damaged during pregnancy. The resulting strands of tissue can tangle up the fetus or parts of the fetus, restricting blood flow and disrupting normal growth. Here’s what you need to know about amniotic band syndrome treatment, symptoms, and more.

What is Amniotic Band Syndrome?

Amniotic band syndrome is a rare congenital disorder. It occurs when fibrous bands of the amniotic sac, which is the lining inside a uterus that contains a fetus, get tangled around the fetus while it develops. ABS syndrome occurs in babies. Many children with amniotic band syndrome have clubfoot as well. Some children affected also have other related conditions, including cleft lip and/or cleft palate.

You may also hear amniotic band syndrome referred to as:

  • ADAM sequence.
  • Amniotic banding.
  • Amniotic sequence syndrome.
  • Constriction ring syndrome.
  • Streeter bands.

Causes of Amniotic Band Syndrome

The exact cause of ABS isn’t known, but researchers do not think the condition is genetic. Amniotic band syndrome usually occurs when the lining of the amniotic sac tears during pregnancy.

Symptoms of Amniotic Band Syndrome

baby feet in a white blanket
Image via Unplash by fengo

ABS is rare overall, and just a small number of those cases involve the bands wrapping around the head of the fetus or the umbilical cord. Most often, the bands of the amniotic sac wrap around a fetus’ arm, fingers, legs, or toes. Doctors believe it happens more frequently in the fingers than the toes. When the bands wrap around the fetus, it can create serious tightening, known as constrictions, on that part of the fetus’ body.

You can imagine constrictions acting a lot like a tight rubber band would to get a sense of what constrictions are like. Sometimes, the amniotic band causes just a small dent around a finger, toe, or limb. However, deeper bands are possible. Deeper bands may lead to serious swelling, or they may cut off blood flow or prevent that body part from growing properly. If bands are tight enough, the constriction can even cause a body part to be amputated in utero.

Most babies that have ABS end up having bands on more than one part of their bodies. How early bands develop tends to determine how severe ABS complications will be for a baby. In general, the earlier bands start to develop, the more time a given body part will be constricted. Earlier constriction often leads to more serious complications, including:

  • Abdominal wall disorders.
  • Cleft lip and/or cleft palate, which is a split in the lip or the palate, respectively.
  • Club hands or club feet, which is the turning inward of the hands or feet, respectively.
  • Constriction rings in the fingers, arms, toes, or legs.
  • Encephalocele, which is a neural tube defect where part of the brain extrudes through the skull.
  • Skull or face deformities.
  • Thoracoschisis, which is a constriction of the thoracic wall.
  • Umbilical cord constriction, which is when blood supply is cut off to the umbilical cord. This complication can be fatal.

If amniotic banding develops later on in a pregnancy, complications tend to be relatively minor. For example, babies with minor ABS complications may only have subtle banding around a toe or finger. Concerns in these cases may be mostly cosmetic.

Amniotic band syndrome is a risk factor for clubfoot, a congenital foot deformity in which the front part of a baby’s foot turns inward and the heel points down. In severe clubfoot cases, the foot will turn so far that the bottom will face sideways or up instead of down.

Amniotic Band Syndrome Diagnosis

In some cases, amniotic band syndrome may be diagnosed before birth. Diagnosis before birth can happen with a routine ultrasound test. If a doctor suspects ABS during pregnancy, they can recommend additional testing in order to diagnose the issue more definitively. Follow-up tests may include:

  • Anatomy ultrasound using a high-resolution ultrasound to more clearly reveal malformations and assess blood flow.
  • Fetal MRI to assess the extent of complications.
  • Fetal echocardiogram, a specialized ultrasound to assess fetal heart function and give a doctor clues about the fetus’ blood circulation.

Most of the time, however, ABS is seen when a child is born. Your child may need to undergo X-rays to determine how serious the problem is in their case.

Amniotic Band Syndrome Treatment

Treatment for amniotic band syndrome will vary from child to child. If your child has shallow bands that don’t interfere with the function of the affected part of their body, they may not need to have surgery. However, if a deeper amniotic band occurs, you child might need to have one or more surgeries to fix the way the affected body part looks or moves. Children that need to have surgery for ABS usually have surgery when they are a year old or older. However, if constriction limits blood flow, they may need to have surgery immediately.

Amniotic band syndrome may be corrected either before birth with fetal surgery or after birth with various surgeries and/or therapies. In the vast majority of ABS cases, treatment does not start until after the baby is born.

Fetal surgery before birth may be necessary in cases when the amniotic banding constricts the umbilical cord or cuts off the supply of blood going to a fetus’ limb. When this happens, a doctor can surgically remove the bands before birth. Fetoscopic amniotic band resection involves surgeons guided by ultrasound imagery as they use a laser or other surgical instrument to cut the constrictive tissue. Because surgery comes with added risk, doctors usually reserve this procedure for the most severe amniotic band syndrome cases.

Once your baby is born, a variety of treatments are available. Amniotic banding may be corrected through plastic surgery, with surgeons releasing the constrictive tissue and repairing the surrounding skin. This is usually done after a child’s first birthday unless the constrictive banding poses serious harm due to its severity.

Some babies also need occupational therapy to get back the strength and coordination in their body part that is affected by the amniotic banding. If ABS has caused the loss of a limb, prosthetics are typically introduced.

If your child needs treatment for podiatric symptoms of amniotic band syndrome or associated clubfoot, Gurnee Podiatry & Sports Medicine can help. Contact us today to find a foot specialist.