Bone, Joint and Muscle Conditions

Amniotic Band Syndrome

What Is Amniotic Band Syndrome?

Amniotic Band Syndrome 1

If bands injure a baby's fingers, the fingers may join as they heal (acrosyndactyly).

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 2

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.