Amniotic band syndrome

Amniotic band syndrome (ABS) occurs when the lining of the amniotic sac, the fluid-filled sac that holds the baby, ruptures or tears, creating string-like strands or “bands” of tissue that can wrap around parts of the fetus.

This rare congenital disorder is referred to by several names, including constriction ring syndrome, amniotic band disruption or congenital constriction band syndrome, among others. 

How does Amniotic Band Syndrome affect my baby?

When these bands wrap around parts of the developing fetus, the constriction can decrease or cut off blood supply to the affected areas, causing a wide range of birth defects.

There may be a single band wrapped around one of the baby’s fingers, causing constriction grooves in the skin, or multiple bands wrapped around the fetal arms or legs, resulting in deformed or amputated limbs. In extreme cases, the bands may constrict the umbilical cord, neck or vital organs, causing life-threatening complications.

Amniotic bands most commonly affect the arms, fingers, legs and toes. The severity of ABS depends on where the bands are located and how tightly they are wrapped around that area. Common birth defects that may be caused by ABS include fused fingers or toes, clubbed feet, cleft lip and underdeveloped limbs.

Cause and Prevalence

Amniotic band syndrome is estimated to occur in anywhere from 1 in 1,200 to 15,000 live births. The exact cause of the damage to the amniotic sac lining is not known.

The condition is believed to develop during the first 20 weeks of pregnancy. Typically the earlier the bands appear, the more severe the complications. No two cases of amniotic band syndrome are exactly alike and the effects can vary greatly from one baby to the next.

Amniotic band syndrome isn’t thought to be genetic or hereditary.

Testing and Diagnosis

The amniotic bands are very thin, making ABS difficult to detect during a routine pregnancy ultrasound. Typically the diagnosis is made at birth.

In some cases, the doctor may suspect ABS based on abnormalities seen in the fetus, such as swelling or deformity of the limbs. If your doctor suspects or diagnoses ABS during pregnancy, you may be referred to a fetal center for a comprehensive evaluation and specialized care. 

At Texas Children’s Fetal Center, we arrange for you to visit as quickly as possible to meet with a team of specialists experienced in the treatment of amniotic band syndrome, including maternal-fetal medicine physicians, fetal and pediatric surgeons, neonatologists and fetal imaging experts. Our specialists will perform a comprehensive evaluation and additional testing to gain critical information about your baby’s condition.

Testing may include:

• Anatomy ultrasound to confirm the diagnosis, evaluate the affected areas, including blood flow, and identify any other abnormalities
• Fetal MRI for more detailed information about the severity of your baby’s condition
• Fetal echocardiogram to evaluate your baby’s heart structure and function and look for any associated cardiac defects

Following this detailed assessment, our specialists will meet with you about the results, answer any questions you have, and provide recommendations based on the needs of your baby, to help you make the most informed decisions regarding care and treatment.

Pregnancy and Delivery

In most cases, treatment for ABS isn’t required during pregnancy. Surgery is performed after the baby is born to repair birth defects caused by the condition.

During pregnancy, you and your baby will be closely monitored with regular ultrasounds to assess fetal growth and development and potential risks.

For the best possible outcomes, babies with ABS should be delivered at a hospital with the expertise and resources required to treat potential complications caused by this rare congenital condition, from premature labor and delivery to the need for immediate surgery at birth. Delivery and postnatal care should be carefully planned and coordinated with a team of maternal-fetal medicine specialists, neonatologists, anesthesiologists, cardiologists and pediatric surgeons experienced in working together to address the diverse needs of babies with ABS.  

Our fetal center team works closely with Texas Children’s pediatric specialists to coordinate your baby’s care from prenatal diagnosis to birth to postnatal care, including the surgical repair of congenital birth defects.

Fetal Surgery for Severe Cases

In rare cases involving life-threatening or severe damage to the fetus, fetal surgery may be an option to remove the bands and reduce further harm to the baby.

Known as fetoscopic amniotic band resection, this surgery is reserved for cases in which the bands are:

• Constricting the umbilical cord and threatening the life of the fetus
• Cutting off the blood supply to a limb and threatening amputation
• Threatening to cause severe deformity

In this procedure, the mother is sedated and given antibiotics and medications to prevent labor. The fetus may also be sedated.

The surgeon makes a small incision in the mother’s abdomen and uterus. Guided by ultrasound imaging, the surgeon inserts a fetoscope (a tiny tube with a camera at the tip) into the uterus. Using surgical instruments or a laser, the surgeon then cuts the band or bands that are endangering the fetus, freeing the constricted body part to prevent further damage to the fetus.

Mother and fetus are monitored closely throughout the remainder of the pregnancy. Immediately after birth, the baby will be examined to determine additional treatment needs.

This minimally invasive surgery may allow preservation of life and/or limb function in cases of severe ABS. Doctors are still studying which cases of ABS benefit most from fetal intervention.

Fetoscopic amniotic band resection involves significant risks, including premature delivery, bleeding and damage to the fetus. Talk with your doctor about the risks involved to make the most informed decision for you and your family.

Treatment After Birth

Treatment for ABS after birth typically involves surgery to repair deformities caused by the constrictive bands. Physical and occupational therapy may also be needed to help children optimize functionality of affected limbs or digits. Prosthetics may be recommended for those who have lost a limb.

The timing of the surgical repairs depends on the child’s needs. Surgery may be performed immediately following delivery, or it may be postponed for several months to allow your baby time to grow.

In some cases your baby may be referred to specialized clinics such as Texas Children’s Hand Program or the Texas Children’s Cleft Lip and Palate Clinic.

Long-Term Outcomes

The long-term outcome for babies with amniotic band syndrome depends on the areas impacted and the severity of the birth defects.

Most cases involving the limbs and extremities typically have excellent long-term outcomes, even in cases of limb amputation. In very rare cases, a baby may have severe deformities or malformations that cannot be repaired and could be fatal.

Why Texas Children’s Fetal Center?

• A single location for expert maternal, fetal and pediatric care. At Texas Children’s Hospital, you and your baby can get the specialized care required for the diagnosis and treatment of amniotic band syndrome all in one location, for highly coordinated care and treatment planning. Our patients are treated in state-of-the-art facilities at Texas Children’s Pavilion for Women and Texas Children’s Hospital, featuring the largest and highest-ranked NICU in the South.
• A skilled, experienced team with proven outcomes. We have a dedicated team of maternal-fetal medicine specialists, fetal and pediatric surgeons, neonatologists, fetal imaging specialists, cardiologists and others who work in concert to care for you and your baby every step of the way. With their combined expertise and unified approach, these physicians offer the best possible care for babies with amniotic band syndrome.
• We care for your child’s needs at every stage of life. Our comprehensive approach starts with your first prenatal visit for ABS and continues through your child’s delivery, postnatal care and childhood, thanks to one of the nation’s leading teams of fetal and pediatric specialists for the treatment of rare birth defects.

Patient Stories

Overcoming odds: how Kai survived amniotic band syndrome

Meet Kai Christensen, a 4-year-old fighter who overcame bleak chances of survival long before he was born. Kai means unbreakable and this little boy, although only 4 years old, is already living up to his name.  

Learn More

Research and Clinical Trials

Perinatal outcome after fetoscopic release of amniotic bands: a single-center experience and review of the literature

Volumes and Outcomes

View data on our experience and outcomes treating amniotic band syndrome

In the News

• Texas Children’s Hospital first in state designated as level IV neonatal intensive care unit