Amniotic Band Syndrome (ABS)

What is Amniotic Band Syndrome?  

Amniotic Band Syndrome (ABS) is a rare condition that can affect the development of a baby during pregnancy. It happens when thin strands of tissue (called amniotic bands) form inside the amniotic sac — the fluid-filled space that surrounds the baby in the womb. These strands can attach to parts of the baby’s body and restrict growth or movement. This may cause a range of effects, from very mild (such as a small indentation on a finger) to more severe (such as a missing or shortened limb).  

What Causes amniotic band syndrome?

The exact cause of ABS is not always known. It is not thought to be genetic or inherited — meaning it usually happens by chance. In most cases, it occurs when the inner lining of the amniotic sac tears early in pregnancy, creating fibrous strands that can wrap around parts of the baby. 

How amniotic band syndrome diagnosed?

Amniotic Band Syndrome may be seen during a routine ultrasound scan. The sonographer might notice: 
- Bands floating in the amniotic fluid 
- Swelling or constriction of a limb 
- Differences in the baby’s limbs or body shape 
 
Sometimes, the diagnosis becomes clearer as the pregnancy progresses or after the baby is born. 

What are the possible effects of amniotic band syndrome?

The impact of ABS varies widely. It depends on: 

-       Where the band attaches 

-       How tightly it restricts the area 

-       When in pregnancy it develops 

 

Possible effects include: 

-       Small indentations or grooves on the skin 

-       Reduced blood flow to a finger, toe, or limb, causing underdevelopment or loss 

-       Fusion or webbing of fingers or toes 

-       In rare cases, effects on the face, chest, or abdomen 

 

Many babies with mild ABS can have normal movement and function after birth. 

How is amniotic band syndrome monitored and treated?

Treatment depends on how the baby is affected: 

-       Most cases are monitored closely with ultrasound to track the baby’s growth and movement. 

-       Fetoscopic Surgery (rare): In very severe cases, specialists may consider surgery during pregnancy to cut the band and free the limb. This is only offered in highly selected cases at specialized centers. 

What happens after birth?

Your baby may need scans after birth. Some babies have surgery to remove the abnormal tissue, especially if it causes symptoms or infections.

Will it happen again?

BPS is not usually inherited, so the chance of it happening again is very low.

What emotional support is available?

Hearing that your baby may have Amniotic Band Syndrome can be upsetting. You are not alone — specialist teams, including fetal medicine experts, paediatric surgeons, and genetic counsellors, can support you and answer your questions. Speaking to a counsellor or joining a support group for parents of children with limb differences may also help.  

What is the recurrence risk?

Amniotic band syndrome usually happens by chance and is very rare. It is not caused by anything you did and it is not passed down in families.

The chance of it happening again in a future pregnancy is extremely low. Most parents who have had a baby affected by amniotic band go on to have completely healthy pregnancies in the future.