What is Spina Bifida?

What is Spina Bifida?

Spina bifida is a spectrum of developmental anomalies related to the closure of the spinal cord sac during early embryologic development. Neural tube defects (NTD) are present at birth, but they don’t always present immediately. For open defects or spine bifida aperta, where the spinal cord doesn’t fully close, there is a visible defect in the spine often causing neurological and spinal cord damage. Most cases of spina bifida, however, are closed. These are called spina bifida occulta and can be more difficult to detect, often only via small markings or dimples in the lumbar skin region.

Both forms of spina bifida occur early during the formation of the baby’s spinal cord and the neural tube, the embryonic structure that eventually forms the brain and spine. While the neural tube usually closes within a month after conception, in spina bifida, it develops without closing all the way.

This type of birth defect occurs early in a woman’s pregnancy, often before she even knows she is pregnant.

Types of Spina Bifida


There are four types of spina bifida, ranging from mild to severe. Each type of spina bifida is associated with different types of conditions.

  • Spina bifida occulta. This type of spina bifida is considered the mildest and most common form. It gets its name from the Latin term, occulta, which means hidden. Spina bifida occulta happens when one or more of the spinal vertebrae develops a malformation; however, the gap in the spine is so small that the spinal cord and nerves are not usually affected.

    Spina bifida occulta usually shows no symptoms; people can go their whole lives before discovering the existence of spina bifida in their spine—it is usually discovered during an X-ray or MRI for another condition completely. If more than one bone is affected with spina bifida, symptoms would usually occur. These symptoms may include:
    • Club foot deformity – This is the most common foot deformity among people with spina bifida, occurring in 30% to 50% of those affected.
    • Weakness or numbness in the legs, making a person appear clumsy.
    • Incontinence. The neurological connection between the brain and the bladder and bowel is broken, causing lack of sphincter control or urinary sensation.
  • Closed neural tube defects. This includes groups of defects with malformations of fat, bone, or membranes covering the spinal cord (meninges). People with closed neural tube defects experience bladder and bowel dysfunction and leg weakness. These problems may increase as the child grows.
  • Myelomeningocele. This type of spina bifida is the most severe. This condition is also called open spina bifida. During the development of the spine, several vertebrae in the lower or middle part of the back have not closed. This opening in the spinal canal enables membranes and spinal nerves to push through during birth. A sac forms on the baby’s back, exposing tissues and nerves. Severe infections can develop causing paralysis, bladder or bowel dysfunction, or death.
  • Meningocele. This is the rarest type of spina bifida formed when spinal fluid fills a sac that protrudes through an opening in the spine. Neither the spinal cord nor nerves are encased in the fluid sac. However, babies born with meningoceles may experience bladder and bowel dysfunction.

Signs & Symptoms of Spina Bifida


Signs of spina bifida vary according to the type of defect present—each type exhibits signs specific to that condition. Some forms of spina bifida are more severe than others. Symptoms of spina bifida are described as:

  • Spina bifida occulta. The most typical sign of spina bifida occulta includes a dimple or tuft of hair at the base of the spine. In addition, a birthmark may be present at the site of the defect. Children with spina bifida occulta do not usually exhibit symptoms or complications; therefore, follow-up requires just routine visits to the pediatrician.
  • Myelomeningocele. The sac is poking through the opening in the baby’s back. With this severe type of spina bifida, there is usually no skin covering the spinal cord or nerves—leaving them exposed. Often, infants born myelomeningocele are unable to move their legs. Their feet may be abnormally shaped (club foot), or their hips and spine may be curved (scoliosis).
  • Meningocele. This type of spina bifida is indicated by a sac of spinal fluid protruding through an opening in the child’s back. Generally, this sac does not contain nerves or the spinal cord and is covered by a thin layer of skin. Bowel and bladder dysfunction are common with meningocele spina bifida.

Causes of Spina Bifida


Scientists and doctors do not know what causes spina bifida. Some believe it is a combination of genetics, environmental surroundings, and nutrition. Some research points to two possible causes.

  • A folic acid deficiency during pregnancy
  • A family history of neural tube defects

In addition, white or Hispanic female children are affected more often than male children for unknown reasons. Research continues to explore ways to prevent and treat spina bifida.

Risk Factors for Spina Bifida

Risk Factors

Though no known cause presently exists, some risk factors for spina bifida include:

  • Folic acid deficiency. A folic acid deficiency in pregnant women increases the risk of spina bifida and other neural tube disorders.
  • Family history. Most children born with spina bifida are born to parents with no known history of the condition; however, a woman born with a neural tube defect has a greater chance of giving birth to a child with the same type of condition, such as spina bifida. In addition, parents who give birth to a child with a neural tube defect have an increased risk of giving birth to another child with the same defect.
  • Medications. Certain medications should be avoided if you are pregnant. For instance, valproic acid, which is used to treat seizures, is known to cause neural tube defects because of its interference with the absorption of folate and folic acid.
  • Diabetes. Women whose diabetes is not well-controlled have a higher risk for giving birth to a child with spina bifida.
  • Obesity. Being obese increases a women’s risk for a baby to develop a neural tube defect such as spina bifida.
  • Increased body temperature. Research findings have associated increased core body temperature from a fever or use of a hot tub or sauna with increasing the risk for a baby to develop spina bifida.

Discuss any potential risk factors that increase the possibility of a baby developing spina bifida. Your doctor can adjust any medications you may take that could affect the development of a healthy baby. In addition, increased doses of folic acid before getting pregnant is believed to positively impact the growth of a healthy baby.



The complications associated with spina bifida vary in severity according to the type of spina bifida a person is diagnosed with. The size and location of the spinal defect determine which part of the body is affected and to what degree.

  • Orthopedic complications. Orthopedic problems are common for most children with spina bifida. Club foot, dislocated hips, and curvature of the spine (scoliosis), in addition to contractures of the knee, hip, or ankle, all affect a child’s ability to walk.
  • Leg and core muscle weakness. This generally happens with neural tube defects and myelomeningocele. People experience leg weakness and loss of sensation in the groin, feet, or legs. Sometimes the sensation is located on one side of the body. The loss of strength and mobility increases with age. Some people may eventually require mobility aids such as walkers, leg braces, or wheelchairs as they age.
  • Chiari II malformation. The brain stem and cerebellum are abnormally situated causing them to push downward into the spinal canal or neck region. It is ordinarily observed from imaging scans of the brain in people affected with myelomeningocele, however, symptoms are not usually present. In cases where symptoms of Chiari II malformation are present, difficulty breathing, swallowing, and weakness in the arms are experienced. Surgery is required to relieve the pressure and facilitate easier breathing.
  • Hydrocephalus. This condition is caused by the abnormal buildup of brain fluid surrounding the brain. This buildup of fluid can damage the brain unless a shunt is implanted allowing for the drainage of the fluid into the abdomen where it is eventually absorbed by the body. This condition is usually seen in people with myelomeningocele. The excess fluid can also be removed from the brain using a procedure called an endoscopic third ventriculostomy or ETV. This procedures creates an alternate exit path for the fluid to flow.
  • Meningitis. Meningitis is a brain or spine infection that affects the meninges, the membrane covering the brain and spine. It is a life-threatening condition that can cause serious neurologic injury.
  • Tethered cord syndrome. This condition can occur with any type of spina bifida. A tethered cord prevents the spinal cord and nerves from moving freely. The tethered cord attaches to tissue causing the cord to be pulled down. Loss of strength, feeling, and problems with bowel and bladder control are common symptoms. This can be due to conditions called fatty filum terminale, thick filum syndrome or occult tethered cord. Surgery may be considered as a treatment option for all of the above and can often treat these symptoms.
  • Bowel & bladder incontinence. Most people with myelomeningocele and closed neural tube defects are affected by bowel and bladder dysfunction. People with this type of symptom may require assistance emptying their bladder or having regularly scheduled bowel movements.
  • Learning disabilities. Children may have difficulty paying attention, understanding instructions, difficulty with memory, and inability to organize or problem solve. Others may have impaired motor skills. Children affected by learning disabilities related to spina bifida do well with individualized education plans (IEPs).
  • Additional complications. People with myelomeningocele and neural tube defects may eventually experience skin ulcers, low bone density, male infertility, obesity, and kidney failure. People with this condition have an increased risk of precocious puberty, which causes premature adult-like changes to occur. Sleep apnea, possibly due to obesity, and depression are common symptoms for people with spina bifida.



It is difficult to formulate an exact method for preventing spina bifida since a precise cause for this condition has not been determined. However, clear findings indicate that increased folic acid before and during pregnancy can significantly reduce a baby’s chance of acquiring spina bifida.

Folic acid is crucial for the development of a healthy baby. Folic acid, a B vitamin, helps the body produce new, healthy cells. Since spina bifida occurs early in pregnancy, doctors recommend that women begin a regimen of 400 micrograms of folic acid every day for at least three months before becoming pregnant.

If spina bifida runs in the family, the doctor may prescribe a 4,000-microgram dose of folic acid as a precaution to reduce the chance of the baby developing this condition.

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Trust NewYork-Presbyterian Kids for Spina Bifida Care

The pediatric physicians and surgeons from NewYork-Presbyterian Komansky Children’s Hospital at Weill Cornell Medicine and NewYork-Presbyterian Morgan Stanley Children’s Hospital at Columbia University have teamed together to create a world-class panel of doctors unsurpassed in their knowledge of pediatric spine conditions or other birth defects.

Call NewYork-Presbyterian to schedule a consultation appointment with one of our pediatric professionals.