A congenital limb defect is when an arm or leg doesn’t form normally as a baby grows in the uterus. The baby is born with the defect.


The exact cause of this type of defect is not known.

Risk Factors

Certain things may increase the chances of this health problem. These include:

  • Conditions that affect the baby in the uterus as it grows. These include genetic abnormalities, growth restriction, and mechanical forces.
  • Exposure by the mother to chemicals or viruses while pregnant
  • Certain medicines
  • Exposure to tobacco smoke


A child with a congenital limb defect has an arm or leg that hasn’t formed normally. The most common of these defects are:

  • No limb at all
  • Part of the limb doesn’t separate, often seen in fingers or toes
  • Duplication, often seen as extra fingers or toes
  • The limb is much larger than the normal limb (overgrowth)
  • The limb is much smaller than the normal limb (undergrowth)


The diagnosis of a congenital limb defect is made at birth. It may be linked to other bone conditions or syndromes. Always talk with your child’s healthcare provider for a diagnosis.


Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

The overall goal for treatment is to give your child a limb that works and looks right. Treatment goals can vary for each child. They may include:

  • Helping your child grow and develop
  • Helping your child feel a sense of independence
  • Encouraging self-care
  • Improving how the limb looks

There is no standard treatment for a congenital limb defect. Treatment choices may include:

  • Artificial limbs (prosthetics)
  • Splints or braces (orthotics)
  • Surgery
  • Rehabilitation, such as physical or occupational therapy

Key Points

  • A congenital limb defect is when an arm or leg doesn’t form normally as a baby grows in the uterus.
  • The exact cause of a congenital limb defect is not known.
  • Certain things may increase the chances of a child being born with such a defect. These include gene problems or exposure to some viruses or chemicals.
  • Treatment depends on the type of congenital limb defect. It may include an artificial limb, surgery, or rehab.

Next Steps

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
  • Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
  • Ask if your child’s condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if your child does not take the medicine or have the test or procedure.
  • If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.