What are congenital limb defects?

Congenital limb defects occur when a portion or the entire upper or lower limb fails to form normally or does not form when the baby is developing in the uterus.

What causes congenital limb defects?

The cause of congenital limb defects is unknown. However, risk factors that may increase the likelihood of a congenital limb defect include the following:

• Conditions, such as genetic abnormalities, growth restriction, mechanical forces, that affect the baby in the uterus during development
• Exposures by the mother to chemicals or viruses while pregnant
• Specific medications
• Possible exposure to tobacco smoke (more research is needed)

How are congenital limb defects diagnosed?

The diagnosis of congenital limb defects is made at birth. The most common congenital limb defects can be classified as follows:

• Complete absence of the limb
• Failure of the portion of the limb to separate (commonly seen in fingers or toes)
• Duplication (commonly seen as extra fingers or toes)
• Overgrowth, the limb is much larger than the normal limb
• Undergrowth, the limb is much smaller than the normal limb
• Congenital constriction band syndrome. Early rupture of the amnion (inner membranes that cover the fetus in utero and contains the amnionic fluid) resulting in bands that may become entangled in the extremities of the fetus, causing immobilization, constrictions of the limbs, amputations, and other deformities.

Congenital limb defects may also be associated with other bone conditions or syndromes. Always consult your child's doctor for a diagnosis.

Learn more about the treatment of congenital limb defects at Children's Hospital of Philadelphia's Limb Preservation and Reconstruction Program.