Health Library

What Is Spina Bifida Occulta?

Spina bifida occulta is when a baby’s backbone (spine) does not fully form during pregnancy. The baby is born with a small gap in the bones of the spine.

The condition is common and happens in about 1 out of 10 people. Usually, it causes no health problems.

What Are the Signs & Symptoms of Spina Bifida Occulta?

Most people with spina bifida occulta (SPY-nuh BIF-ih-duh uh-KUL-tuh) do not even know they have it. They may have a dimple, patch of hair, or a red mark at the base of the spine.

Some people with spina bifida occulta also have a tethered cord. A tethered cord is a spinal cord that can’t move freely inside the spinal canal. Sometimes a tethered cord needs to be released with surgery. Otherwise, it can stretch (especially during a growth spurt) and lead to pain, trouble walking, and loss of bladder (pee) control.

What Are the Other Types of Spina Bifida?

Other kinds of spina bifida include:

• Meningocele: This is when a sac that contains spinal fluid pushes through the gap in the spine. The spinal cord is in its normal place in the spinal canal. The skin over the meningocele often is open.
• Myelomeningocele: This is when a sac that contains part of the spinal cord, its covering, and spinal fluid pushes through the gap in the spine and the skin. It’s visible on the baby’s back.  

How Does Spina Bifida Occulta Happen?

All types of spina bifida happen in the first month of pregnancy. At first, a fetus’ spinal cord is flat. It then closes into a tube called a neural tube. If this tube does not fully close, the baby is born with spina bifida. In spina bifida occulta, the spinal cord and its covering stay in their normal position inside the spinal canal.

What Causes Spina Bifida Occulta?

Doctors don’t know exactly why some babies get spina bifida occulta. A woman may be more likely to have a baby with spina bifida occulta if she:

• takes some types of seizure medicines during pregnancy
• already has had a baby with spina bifida
• has diabetes

Not getting enough of the vitamin folic acid early in pregnancy is linked to meningocele and myelomeningocele, but not spina bifida occulta.

How Is Spina Bifida Occulta Diagnosed?

Spina bifida occulta usually doesn’t cause symptoms. So, it’s often found when an X-ray or other imaging study of the spine is done for a different reason. 

Sometimes spina bifida is diagnosed with an ultrasound after a doctor sees a dimple, patch of hair, or red patch at the base of a baby’s spine.

How Is Spina Bifida Occulta Treated?

Most people with spina bifida occulta do not need medical treatment. Those with a tethered cord might have surgery to let the spinal cord move more freely.

What Else Should I Know?

Most babies born with spina bifida occulta go on live a normal, active life. Help your child get any needed medical care.