by EBSCO Medical Review Board


Spina bifida (SB) is a birth defect. It is a problem with how the spine and spinal cord form. It may cause structures that should be inside the spinal canal to slip out.

The three most common types are:

  • Occulta—a small defect in one or more backbones that usually does not cause health problems
  • Meningocele—membranes that poke through an open part of the spine and can form a cyst
  • Myelomeningocele—membranes that poke through and contain nerve roots or spinal cord and can lead to severe problems
Spina Bifida
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The cause is not always known. It is likely due to:

  • Genetics
  • A low folate diet in the mother
  • Environmental factors

Risk Factors

SB is more likely in females. Other things that may raise the risk are:

  • Other family members who have had SB
  • A mother who had a prior pregnancy with a baby who had a defect of the brain, spine, or spinal cord
  • Low blood level of folic acid in the mother at the time of conception
  • Diabetes in the mother
  • Certain medicines given during pregnancy


SB occulta may not have any symptoms. Some with this type may never know they have SB. There may be a small tuft of hair or change in skin color over the low back.

The symptoms of meningocele and myelomeningocele are:

  • A sac filled with fluid leading out from the baby's spine
  • Spinal cord and tissue that may stick out of the back


Prenatal Testing

A blood test of the mother during pregnancy can predict the risk of SB. If the test predicts a high risk, then two more tests may be done:

  • Amniocentesis—a sample of the fluid around the baby is taken to measure for factors that point to problems of the spine
  • Ultrasound—a test that uses sound waves to look at the fetal spine

After Delivery

After delivery, a meningocele and myelomeningocele can be seen. More tests will be done to find out what health problems the baby may have.

Most children with SB occulta will never be diagnosed. It rarely causes any symptoms. It also has few problems. It may be found during a routine medical exam or x-rays of the lower back.


SB occulta does not need treatment.

Meningocele SB is treated with surgery to remove the cyst.

Treatment for myelomeningocele SB is complex. Options are:

  • Surgery to put the nerves, membrane, and spinal cord back into place before birth or soon after birth
  • Physical therapy to strengthen muscles and learn how to use devices like walkers, braces, and crutches to move


The risk of having a baby with SB can be lowered by taking folic acid supplements before and during pregnancy.


March of Dimes 

Spina Bifida Association of America 


Sick Kids—The Hospital for Sick Children 

Spina Bifida and Hydrocephalus Association of Canada 


National Institute of Neurological Disorders and Stroke (NINDS). NINDS Spina Bifida 2015 Mar 10.

Spina bifida. EBSCO DynaMed website. Available at: Accessed December 18, 2020.

Spina bifida. Healthy Children—American Academy of Pediatrics website. Available at: Accessed December 18, 2020.

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