Amniotic Band Syndrome / ABS
An Overview of Amniotic Band Syndrome
Amniotic Band Syndrome Definition | Cause(s) | Incidence of Amniotic Band Syndrome | Diagnosis | Management of Pregnancy | Fetal Intervention | Contact Us / Request an Appointment
What is Amniotic Band Syndrome / ABS?
Amniotic Band Syndrome / ABS is a group of congenital abnormalities caused by bands of amnion (inner lining of the "bag of waters") that attach to the fetus. Abnormalities result from attachment or constriction that lead to:
- Webbing of fingers and / or toes
- Amputation of limbs
- Severe defects of the head and face, spine, umbilical cord and / or body wall
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What Causes Amniotic Band Syndrome / ABS?
There are several theories as to the cause of Amniotic Band Syndrome / ABS. The most widely accepted is a rupture of the amnion occuring early in gestation. The fibrous bands of amnion that occur from the amniotic rupture encircle the limbs, resulting in tourniquet-like defects and intrauterine amputations.The timing of the rupture is believed to occur between 28 days after conception to 18 weeks of gestation. However, late bands can occur and present at birth with multiple abnormalities of the limbs, even after a normal sonogram was performed earlier in gestation.
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What is the Incidence of Amniotic Band Syndrome / ABS?
Amniotic band syndrome is difficult to diagnose. Estimates of amniotic band syndrome / ABS incidence vary widely, from one in 1,200 to one in 15,000 live births.
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How is Amniotic Band Syndrome Diagnosed?
The earliest amniotic bands have been detected was at 12 weeks gestation, by vaginal ultrasound. Bands may be difficult to detect by ultrasound, and are more often diagnosed by the effect they have on fetal anatomy, as in the case of missing or misshapen limbs.
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How is Pregnancy Managed When Amniotic Band Syndrome is Suspected?
If amniotic band syndrome is suspected, a detailed ultrasound should be conducted to assess any and all abnormalities. A fetal echocardiogram will identify associated cardiac defects. A fetus with amniotic band syndrome should pose no increased risk for the mother during pregnancy.The diagnosis of amniotic band syndrome, however, identifies a pregnancy as being at increased risk for fetal anomalies and premature labor and delivery.
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What is the Fetal Intervention for Amniotic Band Syndrome?
The vast majority of cases of amniotic band syndrome / ABS are best managed after the baby is born. In rare instances, fetal intervention may be possible to cut amniotic bands which may threaten to amputate a limb or constrict the umbilical cord.
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Revised 1/05
