top of page

Spina bifida

Spina bifida is a birth defect that affects the lower back and, sometimes, the spinal cord. It is one of the most common birth defects in the United States, affecting about 1,500 babies each year (1).Spina bifida is the most common of a group of birth defects called neural tube defects (NTDs). The neural tube is the embryonic structure that develops into the brain and spinal cord. The neural tube normally folds inward and closes by the 28th day after conception. When it fails to close completely, defects of the spinal cord and vertebrae (small bones of the spine) can result.

 

How does spina bifida affect a child?
There are three forms of spina bifida:

  1. Occulta: In this mildest form, there are usually no symptoms. Affected individuals have a small defect or gap in one or more of the vertebrae of the spine. A few have a dimple, hairy patch, dark spot or swelling over the affected area. The spinal cord and nerves usually are normal, and most affected individuals need no treatment.

  2. Meningocele: In this rarest form, a cyst or fluid-filled sac pokes through the open part of the spine. The sac contains the membranes that protect the spinal cord, but not the spinal nerves. The cyst is removed by surgery, usually allowing for normal development.

  3. Myelomeningocele: In this most severe form, the cyst holds both the membranes and nerve roots of the spinal cord and, often, the cord itself. Or there may be a fully exposed section of the spinal cord and nerves without a cyst. Affected babies are at high risk of infection until the back is closed surgically, although antibiotic treatment may offer temporary protection. In spite of surgery, affected babies have some degree of leg paralysis and bladder- and bowel-control problems. In general, the higher the cyst on the back, the more severe the paralysis.

What causes spina bifida?
The causes of spina bifida are not completely understood. Scientists believe that both genetic and environmental factors act together to cause this and other NTDs. However, 95 percent of babies with spina bifida and other NTDs are born to parents with no family history of these disorders (2).

Who is at risk of having a baby with spina bifida?
Anyone can have a baby with spina bifida. However, couples who have already had a baby with spina bifida or another NTD have an increased risk of having another affected baby. A couple with one child with spina bifida usually has about a 4 percent chance of having another affected baby, and a couple with two affected children has about a 10 percent chance of having another affected baby (2). Similarly, when one parent has spina bifida, there is about a 4 percent chance of passing the disorder on to the baby (2). Couples who have had an affected baby or have a family history of NTDs should consult a genetic counselor to discuss risks to their future children.

bottom of page