Spina bifida is a birth condition that occurs when the spine and spinal cord do not form properly during the first weeks of pregnancy, leaving an opening in the baby’s spine that can affect the spinal cord and nerves. The condition ranges from very mild forms that cause no symptoms to more serious types that can lead to mobility challenges, bladder and bowel problems, and other health issues throughout life. Understanding this condition helps families and individuals navigate the journey with greater confidence and knowledge.

How Common Is Spina Bifida

Spina bifida is one of the most common birth defects affecting the spine and nervous system in the United States. Each year, approximately 1,278 babies are born with this condition, which translates to about 1 in every 2,875 births.^[2] This makes spina bifida the most frequently occurring permanently disabling birth defect that is compatible with life. Across the country, an estimated 70,000 to 166,000 people currently live with spina bifida, though the exact number may be higher because some mild forms go undiagnosed.^[7][9]

The condition does not affect all communities equally. Hispanic women have the highest rate of having a child with spina bifida, at approximately 3.80 per 10,000 live births. This is followed by non-Hispanic white women at 3.09 per 10,000 births, and non-Hispanic Black or African-American women at 2.73 per 10,000 births.^[2] These differences in occurrence rates highlight the importance of targeted prevention efforts and awareness campaigns within specific communities.

Thanks to advances in medical care and treatment over recent decades, people born with spina bifida are now living much longer than in the past. The median age at death for patients with spina bifida has increased significantly, rising from 41 years in 2011 to 56 years in 2022—a remarkable improvement of more than 36 percent.^[22] This extended lifespan means that individuals with spina bifida are transitioning into adulthood and facing new health challenges that require ongoing care and support.

What Causes Spina Bifida

The exact cause of spina bifida remains not fully understood, but scientists believe it results from a complex combination of genetic and environmental factors working together.^[4] During the first month of pregnancy, a structure called the neural tube—which eventually develops into the baby’s brain and spinal cord—normally forms and closes completely by about 28 days after conception. In babies with spina bifida, a portion of this neural tube fails to close properly, leaving an opening in the spine.^[1]

When the neural tube doesn’t close correctly, the backbone that protects the spinal cord also fails to form and close completely. This opening allows parts of the spinal cord, protective membranes, or nerves to push through, depending on the severity of the condition.^[2] The neural tube closes like a zipper, starting in the middle and progressing upward toward the brain and downward toward the spine. If something interrupts this process, it can affect both the spine and the developing brain at the same time.^[16]

While 95 percent of babies with spina bifida are born to parents with no family history of the condition, genetics still play a role.^[9] If one parent has spina bifida or if a family has already had one child with a neural tube defect, the risk of having another child with the condition increases to about 4 percent.^[10] After having two affected children, the risk for a third child rises to approximately 10 percent.^[9] This pattern suggests that certain genetic factors can make some families more susceptible to the condition.

Risk Factors That Increase the Chance of Spina Bifida

Several factors can increase the likelihood of having a baby with spina bifida. The most significant and well-established risk factor is insufficient folic acid—also known as vitamin B9—before and during early pregnancy.^[10] Women who don’t consume adequate amounts of this essential vitamin have a higher chance of having a baby with spina bifida. Research has shown that if all women of childbearing age took a daily multivitamin containing folic acid, the occurrence of neural tube defects like spina bifida could be reduced by up to 70 percent.^[25]

Certain medications taken during pregnancy can also elevate the risk. Women who take specific antiseizure medications, particularly valproic acid, face an increased chance of having a baby with spina bifida.^[6] This is why it’s crucial for women taking these medications to consult with their healthcare providers before becoming pregnant, to discuss potential alternatives or additional preventive measures.

Medical conditions affecting the mother can contribute to the risk as well. Women with diabetes that is not well controlled during pregnancy have a higher likelihood of having a baby with spina bifida.^[2] Similarly, obesity increases the risk, as does experiencing high fever or overheating during the early weeks of pregnancy.^[4] These factors underscore the importance of good overall health and medical management before and during pregnancy.

Types of Spina Bifida and Their Symptoms

Spina bifida occurs in several different forms, ranging from very mild to quite severe. The three main types are spina bifida occulta, meningocele, and myelomeningocele. Each type causes different symptoms and presents different challenges depending on where the opening occurs along the spine and how much of the spinal cord and nerves are affected.^[1]

Spina Bifida Occulta

Spina bifida occulta is the mildest and most common form of the condition. The term “occulta” means “hidden,” because in this type, a small gap exists in one or more of the vertebrae—the bones that make up the spine—but the opening is covered by skin.^[1] The spinal cord and nerves remain normal and undamaged. It occurs in about 10 to 20 percent of the general population, though many people never know they have it.^[17]

Most people with spina bifida occulta experience no symptoms at all. The condition is often discovered accidentally during an X-ray or other imaging test performed for an unrelated reason.^[5] Occasionally, there might be a visible sign on the skin over the spine, such as a small dimple, a tuft of hair, a dark spot, or a small swelling. Some individuals with spina bifida occulta may experience back pain or neurological symptoms later in life, but this is uncommon.^[7]

Meningocele

Meningocele is a rare form of spina bifida. In this type, the protective membranes around the spinal cord, called meninges, push out through the opening in the spine, forming a fluid-filled sac visible on the baby’s back.^[2] However, the spinal cord itself remains inside the spinal column and is usually not in the sac. Because the spinal cord is typically unaffected, there is often little or no nerve damage.

Babies born with meningocele may have mild disabilities or no disabilities at all. Some children might experience minor problems with walking or with bladder and bowel control, but many develop normally. The visible sac is usually covered by skin and requires surgical correction, but the long-term outlook is generally favorable compared to more severe forms.^[9]

Myelomeningocele

Myelomeningocele is the most serious and most common form of spina bifida, accounting for about 75 percent of all cases.^[9] In this type, not only do the protective membranes push through the opening, but part of the spinal cord and nerves also protrude from the back, contained within a fluid-filled sac. The sac may be covered by skin, or in some cases, the tissue and nerves are exposed directly to the environment.^[3]

The exposure of delicate spinal cord tissue to amniotic fluid during pregnancy causes progressive nerve damage. This damage results in a range of disabilities that vary depending on where along the spine the opening occurs. When the defect is located higher on the spine, near the head, the effects are typically more severe. Children with higher-level defects often have paralyzed legs and use wheelchairs for mobility. When the opening is lower on the spine, near the hips, children may have more use of their legs and might walk with braces, crutches, or walkers, or even without assistance.^[18]

Common symptoms and complications of myelomeningocele include weakness or complete paralysis of the legs, loss of sensation in the lower body, and problems with bladder and bowel control. Many children—between 70 and 90 percent—with myelomeningocele also develop hydrocephalus, a condition where excess fluid accumulates in the brain, causing the spaces in the brain to enlarge and the head to swell.^[3] This requires treatment with a surgically implanted tube called a shunt to drain the fluid and prevent brain damage.^[15]

Other complications that can occur with myelomeningocele include a tethered spinal cord, where the spinal cord becomes abnormally attached to surrounding tissue and cannot move freely. As a child grows, this stretching can cause additional nerve damage, leading to back pain, worsening leg weakness, and changes in bladder or bowel function.^[15] Many children also develop orthopedic problems such as scoliosis—an abnormal curvature of the spine—hip dislocation, or club foot.^[4]

Despite these significant physical challenges, most people with myelomeningocele have normal intelligence. However, some may experience learning difficulties, particularly with executive functions like planning and problem-solving, motor skills, and memory.^[4] Early intervention and ongoing educational support can help children reach their full potential.

Preventing Spina Bifida

While not all cases of spina bifida can be prevented, taking specific steps can significantly reduce the risk. The most important and effective prevention measure is ensuring adequate folic acid intake before and during early pregnancy. All women who could become pregnant should take 400 micrograms of folic acid daily.^[2] For women who have already had a child with a neural tube defect, healthcare providers typically recommend a higher dose of folic acid—around 4,000 micrograms daily—starting at least one month before trying to conceive.

Folic acid is a B vitamin that helps build healthy cells, and it plays a crucial role in the proper development of the neural tube. Foods naturally rich in folate include leafy green vegetables, citrus fruits, beans, and fortified cereals. However, it can be difficult to get enough folate from diet alone, which is why supplementation is recommended. In many countries, including the United States, flour and grain products are fortified with folic acid to help increase intake across the population.^[10]

Managing existing medical conditions is also important for prevention. Women with diabetes should work with their healthcare team to achieve good blood sugar control before becoming pregnant. Those taking antiseizure medications should discuss with their doctors whether alternative medications might be safer during pregnancy, though it’s important never to stop taking prescribed medications without medical guidance.^[2] Maintaining a healthy weight before pregnancy and avoiding excessive heat or high fevers in early pregnancy can also help reduce risk.

How the Body Is Affected by Spina Bifida

Spina bifida affects the body by disrupting the normal structure and function of the spine and nervous system. The spine, made up of individual bones called vertebrae, normally surrounds and protects the delicate spinal cord. The spinal cord is a bundle of nerves that carries messages between the brain and the rest of the body, controlling movement, sensation, and organ function. When the spine doesn’t form properly, this protective housing is incomplete, leaving the spinal cord vulnerable to damage.

In more severe forms of spina bifida, the exposed spinal cord and nerves fail to develop normally. Continuous exposure to amniotic fluid during fetal development causes progressive injury to these delicate structures.^[3] This nerve damage interrupts the normal flow of signals between the brain and body parts below the level of the spinal defect. As a result, muscles may not receive proper signals to contract, leading to weakness or paralysis. Similarly, sensory nerves can’t send information back to the brain, causing loss of feeling or sensation in affected areas.

The bladder and bowel are particularly affected because the nerves that control these organs emerge from the lower part of the spinal cord, which is often where spina bifida occurs. Without proper nerve signals, the bladder may not empty completely or may leak urine. The bowels may not function normally, leading to constipation or incontinence. These issues require careful management throughout life to prevent complications like urinary tract infections or kidney damage.^[15]

When hydrocephalus develops, the normal circulation and absorption of cerebrospinal fluid—the clear fluid that cushions the brain and spinal cord—is disrupted. This fluid builds up in the brain’s cavities, called ventricles, causing increased pressure. If left untreated, this pressure can damage brain tissue and affect cognitive development and function. A shunt surgically placed to drain excess fluid redirects it to another part of the body, usually the abdomen, where it can be safely absorbed.^[24]

The musculoskeletal system is also affected by spina bifida. When muscles don’t receive proper nerve signals, they may not develop strength normally, leading to muscle imbalance around joints. This imbalance can cause bones to grow in abnormal positions, resulting in conditions like hip dislocation, club foot, or scoliosis. As children with spina bifida grow, these orthopedic issues may require bracing, physical therapy, or corrective surgery to maintain function and prevent pain.^[13]

Many people with spina bifida develop sensitivity to latex, a natural rubber found in many medical products like gloves, catheters, and bandages. Scientists believe this allergy develops from repeated exposure to latex products during the many medical procedures and surgeries that people with spina bifida undergo, especially in childhood. This latex sensitivity can range from mild skin reactions to potentially serious breathing difficulties, requiring careful avoidance of latex-containing products throughout life.^[18]