Spina Bifida

Spina bifida (SPY-na BI-fi-da) is a birth defect in which the spinal column does not form properly, leaving a gap or opening in the spine.

Brian Teaches Class

As part of a sixth-grade science project, Brian chose to report on a condition called spina bifida. He showed a picture of the ring-shaped bones, or vertebrae (VER-tuh-bray), of the spine and demonstrated how the vertebrae protect the spinal cord and anchor muscles. He explained that in people with spina bifida, some of the bony plates that should cover the spine do not close, leaving an unprotected opening at the back of the spine.




Babies born with spina bifida often have an unprotected opening at the back of the spine.





Babies born with spina bifida often have an unprotected opening at the back of the spine.
Illustration by Frank Forney. © 2016 Cengage Learning®.

What Is Spina Bifida?

Spina bifida is a Latin term meaning “split spine” or “open spine.” It is the most common of several birth defects called neural tube defects. The neural tube contains the cells that ultimately make the spinal cord, spine, and brain, and it develops during the first three to four weeks of pregnancy (often before a woman even knows that she is pregnant).

Spina bifida results when the sides of the neural tube fail to join together properly, leaving an open area. Often the gap occurs in the lower back at the base of the spine. The spinal cord is part of the central nervous system, which allows individuals to move and sense the world around them. Because spina bifida involves the central nervous system, it can cause a range of physical and mental problems.

Is There Prenatal Testing for Spina Bifida?

Sometimes parents can find out whether their baby has spina bifida before birth. Several commonly used tests can help provide this information.

Maternal-serum Alpha-fetoprotein (AFP) test

This test is performed between the sixteenth and eighteenth weeks of pregnancy. Alpha-fetoprotein is a substance made by the developing fetus. Because the mother and fetus are connected via their circulatory systems, AFP from the fetus gets into the mother's bloodstream. By measuring the amount of AFP in the mother's blood, doctors get an indication of the likelihood that the fetus has certain birth defects. This test does not give a definite answer, and high levels of AFP only suggest that the fetus might have spina bifida. If AFP levels are high, doctors repeat the test. If the results are again high, doctors order other tests to confirm that the fetus has spina bifida. Many times, high AFP readings are false alarms and the baby is just fine.

Ultrasound

Medical professionals can use ultrasound to confirm or rule out spina bifida. An ultrasound works by bouncing sound waves off internal structures. A computer converts the returning sound waves into an image of the fetus inside the uterus. Sometimes the defect in the developing spine is visible on the ultrasound image.

Amniocentesis

This is a procedure medical professionals can perform between the sixteenth and eighteenth week of pregnancy. In this procedure, a needle passes through the mother's belly into her uterus to collect some of the fluid that surrounds the fetus. This fluid, called amniotic fluid, contains cells and chemicals from the fetus. In this fluid, medical professionals can measure the levels of AFP to help them determine whether the fetus may have spina bifida. Like the AFP test of the maternal blood, however, the test of the amniotic fluid does not give a definite answer.

Is Spina Bifida Always Serious?

Spina bifida is a common birth defect, but it does not always cause serious problems. At birth, the gap may be so slight that it is invisible and harmless. However, sometimes the spinal cord bulges through the malformed vertebrae and serious neurological (nerve) problems result.

Spina bifida occulta

Brian was born with spina bifida occulta, the mildest form of spina bifida. Occulta means hidden, and in many cases, the gap in the spine is never detected. Often, an opening in one or two of the vertebrae occurs but the spinal cord is not affected. A dimple, a birthmark, or a patch of hair may be visible on the skin overlying the site of the gap.

Scientists estimate that up to 40 percent of all Americans have this form of spina bifida, but few ever know they have it. Most people with spina bifida occulta never need treatment. Brian was an exception. He needed surgery because as he grew, the lower end of his spinal cord got caught against his vertebrae, causing him to have problems controlling his bladder. The doctors “unhooked” the spinal cord and closed the gap surgically.

Spina bifida manifesta

Spina bifida manifesta includes two forms of spina bifida that together represent one of the most common disabling birth defects. On average, one out of 1,000 babies in the United States is born with one of these forms, either meningocele (me-NING-go-seel) or myelomeningocele (MY-e-lo-me-NING-go-seel).

Meningocele

Of babies born with spina bifida manifesta, about 4 percent have the meningocele form. The meninges (me-NIN-jez) consist of three layers of tough membranes that cover and protect the brain and spinal cord. The brain and spinal cord are also bathed in a fluid called cerebrospinal fluid (CSF). A meningocele is a CSF-filled sac formed when the meninges balloon through the gap in the vertebrae. It looks like a large blister covered by a thin layer of skin. The sac can range in size from as small as a grape to as large as a grapefruit.

A meningocele is harmless if the sac contains only CSF. However, if nerves are caught in the sac, the affected baby can have problems controlling muscles and the bladder. Babies with this form of spina bifida usually have surgery during infancy to put the meninges back inside the vertebrae and to close the gap in the vertebrae.

Myelomeningocele

When many people think of spina bifida, they think of the myelomeningocele form. Approximately 96 percent of babies born with spina bifida manifesta have myelomeningocele, and it is the most serious type of spina bifida. As in meningocele, the meninges bulge through the gap in the spine, but in myelomeningocele, part of the spinal cord bulges outward as well. The sac may be covered with skin, or the nerves may actually be exposed.

Preventing Spina Bifida: The Role of Folic Acid

Scientists have linked spina bifida to a deficiency of folic acid during the first weeks of pregnancy. One of the B vitamins, folic acid is essential for proper functioning of the human body. During pregnancy and during fetal development, the mother's body and the fetus's body need more folic acid than usual.

Scientists estimate that the incidence of spina bifida can be decreased by about 70 percent if all women of childbearing age consume 0.4 mg of folic acid each day.

Good sources of folic acid include dark-green leafy vegetables (such as spinach and broccoli); eggs; and orange juice. In addition, the U.S. Food and Drug Administration mandates that breads, enriched grains, and cereals have folic acid added to them. Even with folic acid supplements added to common foods, the average American diet does not contain 0.4 mg of folic acid per day. Most multivitamins, however, contain the recommended dose of folic acid.

Myelomeningocele requires surgery within 24 to 48 hours of birth. Surgeons must close the gap in the vertebrae to protect the spinal cord and prevent infection. They also must treat hydrocephalus, if it is present. They do this by placing a device called a shunt into the brain to drain excess fluid and relieve pressure on the brain.

What Causes Spina Bifida?

Spina bifida sometimes runs in families, which suggests that genes may play a role in some cases. In 90 to 95 percent of cases, however, babies are born to families that have never before had a child with the condition. Mothers who have diabetes, a high fever during pregnancy, or who have taken the drug valproic acid to treat epilepsy * seem to have a greater chance of having a baby with spina bifida than other mothers. In addition, scientists have linked a deficiency of folic acid (a B vitamin) in the mother's diet to a higher risk of having a baby with spina bifida. Adding folic acid to the diet significantly reduces the chance that a woman will give birth to a baby with spina bifida.

Living with Spina Bifida

Most children with spina bifida occulta, and many with meningocele, live normal lives without any impairment. Children born with myelomeningocele, however, often have multiple problems resulting from damage to their spinal cord. Surgery to repair the gap in the vertebrae and to place a shunt in the brain can prevent further damage to the nervous system. It cannot, however, reverse the nerve problems that are already present at birth.

The severity of symptoms caused by myelomeningocele varies from child to child. A common problem is the inability to control the bowel and bladder. Catheters * , diapers, and attentive caregivers can all play a role in helping control this problem and/or in alleviating associated embarrassment.

Many affected children cannot walk without crutches or leg braces, and many need a wheelchair. In addition, some children have learning difficulties, particularly with reading and math. Special education classes can help them in their academic work.

Children with spina bifida often develop sensitivity or an allergy to latex (natural rubber), which is used in such healthcare products as gloves and catheter tubes. The allergy probably develops because they come into contact with latex so often and at such a young age as a result of their medical care.

Even with the disabilities caused by spina bifida, children who have the condition often live well into adulthood. With the help of early and continuing medical, psychological, and educational treatment, children with spina bifida can lead full and productive lives.

See also Birth Defects: Overview • Hydrocephalus • Incontinence • Paralysis • Spinal Cord Injury

Resources

Books and Articles

Copp, Andrew J., et al. “Spina Bifida.” Nature Reviews (April 30, 2015). Available at: http://www.nature.com/articles/nrdp20157 (accessed July 11, 2016).

Travis, Karen Snyder. Christal: Coping with Spina Bifida. Wellesley, MA: Branden Books, 2014.

Websites

Centers for Disease Control and Prevention. “Spina Bifida.” http://www.cdc.gov/ncbddd/spinabifida (accessed July 11, 2016).

Foster, Mark R. “Spina Bifida.” Medscape (updated April 21, 2016). http://emedicine.medscape.com/article/311113-overview (accessed July 11, 2016).

National Institute of Neurological Disorders and Stroke. “Spina Bifida Fact Sheet.” http://www.ninds.nih.gov/disorders/spina_bifida/detail_spina_bifida.htm (accessed July 11, 2016).

Organizations

March of Dimes. 1275 Mamaroneck Ave., White Plains, NY 10605. Telephone: 914-997-4488. Website: http://www.marchofdimes.org (accessed July 11, 2016).

Spina Bifida Association. 1600 Wilson Blvd., Suite 800, Arlington, VA 22209. Telephone: 202-944-3285. Website: http://www.spinabifidaassociation.org (accessed July 11, 2016).

* epilepsy (EP-i-lep-see) is a condition of the nervous system characterized by recurrent seizures that temporarily affect a person's awareness, movements, or sensations. Seizures occur when powerful rapid bursts of electrical energy interrupt the normal electrical patterns of the brain.

* catheters (KAH-thuh-ters) are small plastic tubes placed through a body opening into an organ (such as the bladder) or through the skin directly into a blood vessel. They are used to give fluids to or drain fluids from a person.

  This information is not a tool for self-diagnosis or a substitute for professional care.