Birth Defects of Face Fingers and Toes – Surgical Treatments of Amniotic Band Syndrome
The amniotic sac is a thin protective covering that hovers around the baby while it is still developing in the womb. In simple words, it can be considered as a safe house that prevents external shocks and disturbances from entering the womb. However, in rare cases, this protective covering can prove dangerous to the developing baby. Find out how and why this happens in below paragraphs.
Amniotic band syndrome
While the amniotic sac is considered relatively safe, sometimes this protective covering of the fetus can be severely damaging. Amniotic band syndrome (ABS) is a group of birth defects that occur when the fibrous bands or strands present in the sac get entangled around the fetus.
The birth defects may cover the face, arms, fingers, legs or toes. The condition is also known with other names including:
- Intrauterine amputation
- Streeter’s amputation
- Annular band constriction
- Amniotic Deformity, adhesions, and mutilations
- Aberrant tissue bands
- Limb-body wall complex
How many people have amniotic band syndrome?
It’s a rare condition and occurs once in about 1200-15000 live births. This seems to be a fairly uncommon condition; however, amniotic band syndrome occurrence is about 178 in 10,000 miscarriages. The impact of this disorder can be varied, widespread and drastic, ranging from mild to severe.
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What causes amniotic band syndrome?
While there is no definitive cause as to why this condition occurs, there are several theories out of which, two are considered important. But it is believed that damage to the amnion, a part of the placenta can cause amniotic band syndrome.
This is the most popular theory among the medical experts. The amniotic sac is made up of inner and outer layer. Sometimes, the inner wall linings (amnion) of the amniotic sac tear without any damage to the outer layering and start floating in the amniotic fluid. This can expose the fetus to the bands of the membrane and there are increased chances of entangling or entrapment of fetus body parts.
This theory suggests that hindrance of normal blood flow to the baby can cause deformities.
It is thought that amniotic bands can occur in early pregnancy and the impact is deeper as compared to late pregnancy.
Signs and symptoms – How amniotic band syndrome affect my baby?
The condition shows a range of presentation and patterns with no two cases being similar. These include:
- Malformation of hands and limbs or unequal size of the limbs
- A gap on the head or torso
- Crease marks on body parts including fingers, hands and legs due to entanglement
- Swelling on various parts of the body
- Webbed fingers or toes
- Fingers or toes fused together
- Deformation of nails
- Abnormal gap in the face or cleft lip and palate
- Clubbed feet due to band entangling around the legs, restricting its mobility
- Defect of the abdomen and the chest wall
- Part of the brain and skull missing (Anencephaly)
- Part of the brain extruding through the skull (Encephalocele)
- Constriction of the umbilical cord which in turn, cuts off the blood supply to the baby
Are there any risk factors of amniotic band syndrome?
While experts are still trying to figure out the exact cause of amniotic band syndrome, some studies indicate certain risk factors of this condition. These include:
- Prior uterine surgeries
- Sample taken during prenatal genetic testing (chorionic villus sampling (CVS). The puncturing of the amniotic sac to retrieve the sample can cause the banding.
- Exposure to the drug misoprostol which is commonly given to induce abortion
- Smoking and drug use during pregnancy
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Diagnosis – How would I know of amniotic band syndrome?
The condition is usually diagnosed at birth. Ultrasound test at around the third month of pregnancy can also detect amniotic band syndrome, however, it’s very difficult for the doctors. Misdiagnosis is very common in this case. Some doctors may use 3D ultrasound and MRI for more accuracy.
Other tests include:
Doppler Blood Flow Study
It measures the blood flow in the vessels by creating high-frequency ultrasound.
It examines the structure and function of the heart of the unborn child. It is typically done in the second trimester or between 18-24 weeks.
Is amniotic band syndrome treatable? Surgeries and management during pregnancy
The treatment of amniotic band constriction will depend on a variety of factors. These include the affected region, the severity of the damage and the general health condition of the child. In majority of the cases, the condition is not treatable until the child is born. The doctors may perform one or more of the below surgical procedures:
Fetal surgery or foetoscopy
This procedure is conducted during the pregnancy. A pencil-tip sized instrument with a tiny camera is inserted into the uterus to break apart or remove the band away from the body parts of the baby. The results sometimes can be dramatic, as in one such case when surgeon removed a band from the leg of the baby, it turned pink as the blood flow restored in the area.
On the contrary, fetal surgery is surrounded by several controversies including the risk of infection, premature delivery and damage to the umbilical cord. However, as a small number of studies have shown a promising success rate of 50 percent, this is truly a hope for many people.
This procedure is conducted on the 3-6 months old infant with cleft lift and palate. Various other factors including the extent of damage and feeding capabilities of the infant has to be taken into consideration.
Newborn with missing limbs or who lose a large portion of their hands and legs are generally treated with prosthetics. A very popular example is of 3D printed models.
Due to potential risks associated with amniotic band syndrome, precautions must be taken during delivery. In most cases, a c-section is the recommended method in order to prevent further entanglement. It might be a little frightening to your senses if you come to know that your unborn baby has amniotic band syndrome.
So, it is better to get through multiple sessions with your gynecologist well in advance to know the risks involved with your child as well as management techniques.
1. Amniotic band syndrome(2018). NIH read more
2. Amniotic Band Syndrome(2015). NORD read more
3. Barros M. et al.(2014).Revisiting amniotic band sequence: a wide spectrum of manifestations read more
4. Amniotic band syndrome(2015). MedlinePlus read more