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Spina bifida
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Spina Bifida

Spina bifida is a neural tube defect where the spine fails to close completely, potentially causing nerve damage, but many individuals live into adulthood with surgery and treatment.

Overview

Spina bifida is a condition in which the neural tube, a layer of cells that ultimately develops into the brain and spinal cord, fails to close completely during the first few weeks of embryonic development. As a result, when the spine forms, the bones of the spinal column do not close completely around the developing nerves of the spinal cord. Part of the spinal cord may stick out through an opening in the spine, leading to permanent nerve damage. Because spina bifida is caused by abnormalities of the neural tube, it is classified as a neural tube defect.

Types and Severity

Children born with spina bifida often have a fluid-filled sac on their back that is covered by skin, called a meningocele. If the sac contains part of the spinal cord and its protective covering, it is known as a myelomeningocele. The signs and symptoms of these abnormalities range from mild to severe, depending on where the opening in the spinal column is located and how much of the spinal cord is contained in the sac.

In a milder form of the condition, called spina bifida occulta, the bones of the spinal column are abnormally formed, but the nerves of the spinal cord usually develop normally. Unlike in the more severe form of spina bifida, the spinal cord does not stick out through an opening in the spine. Spina bifida occulta most often causes no health problems, although rarely it can cause back pain or changes in bladder function.

Symptoms and Complications

Related problems can include:

  • A loss of feeling below the level of the opening
  • Weakness or paralysis of the feet or legs
  • Problems with bladder and bowel control

Some affected individuals have additional complications, including a buildup of excess fluid around the brain (hydrocephalus) and learning problems. With surgery and other forms of treatment, many people with spina bifida live into adulthood.

Frequency

Spina bifida is one of the most common types of neural tube defect, affecting an estimated 1 in 2,500 newborns worldwide. For unknown reasons, the prevalence of spina bifida varies among different geographic regions and ethnic groups. In the United States, this condition occurs more frequently in Hispanics and non-Hispanic whites than in African Americans.

Causes and Risk Factors

Spina bifida is a complex condition that is likely caused by the interaction of multiple genetic and environmental factors. Some of these factors have been identified, but many remain unknown.

Genetic Factors

Changes in dozens of genes in individuals with spina bifida and in those of their mothers may influence the risk of developing this type of neural tube defect. The best-studied of these genes is MTHFR, which provides instructions for making a protein that is involved in processing the vitamin folate (also called vitamin B9). A shortage (deficiency) of this vitamin is an established risk factor for neural tube defects like spina bifida. Changes in other genes related to folate processing and genes involved in the development of the neural tube have also been studied as potential risk factors for spina bifida. However, none of these genes appears to play a major role in causing the condition.

Environmental Factors

Researchers have also examined environmental factors that could contribute to the risk of spina bifida. Folate deficiency appears to play a significant role. Studies have shown that women who take supplements containing folic acid (the synthetic form of folate) before they get pregnant and very early in their pregnancy are significantly less likely to have a baby with spina bifida or a related neural tube defect.

Other possible maternal risk factors for spina bifida include:

  • Obesity
  • Exposure to high heat (such as a fever or use of a hot tub or sauna) in early pregnancy
  • The use of certain anti-seizure medications during pregnancy

However, it is unclear how these factors may influence the risk of spina bifida.

Inheritance

Most cases of spina bifida are sporadic, which means they occur in people with no history of the disorder in their family. A small percentage of cases have been reported to run in families; however, the condition does not have a clear pattern of inheritance. Family members (such as siblings and children) of people with spina bifida have an increased risk of the condition compared with people in the general population.

Other Names

  • Cleft spine
  • Open spine
  • Rachischisis
  • Spinal dysraphism

Frequently Asked Questions

Children often require multidisciplinary management: urologic care for bladder dysfunction (clean intermittent catheterization, medications), orthopedic monitoring for scoliosis or foot deformities, physical therapy to maximize mobility, and neuropsychological support for learning challenges. Regular follow‑up with a spina bifida clinic helps coordinate these services and address complications early.
First‑trimester ultrasound (nuchal translucency scan) can sometimes visualize open neural tube defects, but the definitive screening is a detailed anatomy ultrasound at 18–22 weeks, which can identify the spinal defect and associated findings. Maternal serum alpha‑fetoprotein (AFP) testing in the second trimester is another screening tool; elevated AFP may indicate an open defect and prompts further imaging.
The CDC recommends 400 µg of folic acid daily for all women of childbearing age, starting at least one month before conception and continuing through the first 12 weeks of pregnancy. Women with a personal or family history of neural tube defects are advised to take 4 mg daily under medical supervision.
In‑utero (fetal) repair between 19–26 weeks gestation has been shown to reduce the need for shunting and improve motor outcomes compared to postnatal repair, but it is offered only at specialized centers after careful maternal‑fetal evaluation. If fetal surgery is not feasible, postnatal repair is typically performed within the first few days of life to protect the exposed neural tissue and prevent infection.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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