What is Amniotic Band Constriction?

What is Amniotic Band Constriction?

Last update: 04 May, 2018

Amniotic band constriction is related to a series of birth defects. Also known as amniotic band syndrome, it occurs when certain parts of the fetus’s body become tangled in a fiber that restricts its growth. 

This syndrome usually affects the arms, legs, fingers or toes.

Amniotic band constriction causes diverse defects, depending on what part of the body is involved. 

In extreme cases, when the fiber constricts a more delicate area, it may result in fetal death. For example, it can cause miscarriage if blood flow is restricted in the umbilical cord.

There is no way to predict amniotic band constriction, as it occurs completely at random. There is no genetic predisposition or any other specific risk factor.

Furthermore, its occurrence has absolutely nothing to do with previous or future pregnancies. In other words, if this occurs during one pregnancy, there is no reason to believe it will happen again.

At the same time, if it didn’t occur in a prior pregnancy, that doesn’t mean it can’t happen in a future pregnancy.

The development of amniotic band syndrome

What is Amniotic Band Constriction?

Specialists state that this disorder starts to develop during the first 28 days after conception

However, it can present itself up to 18 weeks later. If the syndrome appears around 45 days, the consequences can be catastrophic.

The smaller the fetus is, the greater the chances of the amniotic band affecting vital organs. In other words, the constriction can produce defects in the cranium and in very important organs.

If the fetus is more mature, then the effects are likely to be less serious because the baby is more resistant.

Some studies seemed to indicate that the appearance of this syndrome was related to the realization of amniocentesis. However, scientists later discovered that this type of lesion can occur even in the absence of this procedure.

In some cases, medical specialists were unable to detect the presence of amniotic band syndrome earlier than 21 weeks, via ultrasound. But doctors assert that it’s is very difficult to discover this defect before the baby is born.


On certain occasions, it’s easy to detect this disruption through a simple ultrasound. As we’ve said, it can appear during different stages of gestation. This means that specialists can make a diagnosis during routine examinations. 

It’s important to keep in mind that most children that develop amniotic band constriction are born without complications.

In the majority of pregnancies involving this defect, the baby has a normal birth close to his or her due date.

Even when doctors manage to detect the syndrome beforehand, there may not be additional effects.

The main problem with amniotic band syndrome is that it can be difficult to recognize during an ultrasound.

Amniotic bands are very thin, which means they’re hard to make out during the first 12 weeks of gestation. 

After this point, a doctor may begin to suspect constriction when further exams reveal the resulting damage.

As stated, an ultrasound doesn’t always suffice in the detection of amniotic band constriction. If a specialist suspects damage, then he or she may recommend an MRI.

A Doppler study can also confirm the presence of constriction. However, the syndrome can easily go undetected until the baby is already born.

What is Amniotic Band Constriction?

The effects of amniotic band constriction

The effects of amniotic band constriction vary greatly depending on what part of the baby’s body is affected. The most common areas that this syndrome affects are the arms, legs, hands, fingers and toes.

In these cases, the constriction of the amniotic fiber may cause a deformation in the affected area, or even total amputation.

Amniotic band syndrome can cause cleft lip or cleft palate when the fiber crosses the baby’s face. Furthermore, it’s the main cause of clubfoot.

The constriction that this condition inflicts can also bring about birth defects that are related to incapacitating malformations or disfigurations.

Specialists affirm that every case is unique, because the location of the constriction is completely up to chance.

Furthermore, the severity of the damage depends on related factors such as the time of gestation and the placement of the amniotic fiber.

Some of the most common cases of amniotic band constriction include:

  • Mild damage due to the appearance of simple folds that don’t impede the function of the organ
  • Deep creases that require surgery because they cut off circulation
  • Constriction of extremities at varying spots. The constriction of fingers tends to inflict more severe damage, preventing their development altogether
  • Congenital amputation, as the result of insufficient blood flow in the amputated limb. When the child is born, he or she will have already lost a body part during formation
  • Fusion of damaged body parts, especially as the result of defects like syndactyly – the fusing together of 2 or more digits
  • Distrophy of the finger or toenails
  • Underdevelopment of a member, resulting in a discrepancy in its length
  • Joint contraction as a result of the pressure on the nerve from band constriction
  • Encephalocele
  • Acrania, which is the lack of the development of the bones of the cranium
  • Anencephaly, which occurs when the brain doesn’t develop
  • Hip dislocation
  • The formation of false joints, also known as pseudoartrosis

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.