Spina bifida is a birth defect that affects the lower back and, sometimes, the spinal cord. It is one of the most common birth defects in the United States, affecting about 1,500 babies each year (1).
Spina bifida is the most common of a group of birth defects called neural tube defects (NTDs). The neural tube is the embryonic structure that develops into the brain and spinal cord. The neural tube normally folds inward and closes by the 28th day after conception. When it fails to close completely, defects of the spinal cord and vertebrae (small bones of the spine) can result.
There are three forms of spina bifida:
- Occulta: In this mildest form, there are usually no symptoms. Affected individuals have a small defect or gap in one or more of the vertebrae of the spine. A few have a dimple, hairy patch, dark spot or swelling over the affected area. The spinal cord and nerves usually are normal, and most affected individuals need no treatment.
- Meningocele: In this rarest form, a cyst or fluid-filled sac pokes through the open part of the spine. The sac contains the membranes that protect the spinal cord, but not the spinal nerves. The cyst is removed by surgery, usually allowing for normal development.
- Myelomeningocele: In this most severe form, the cyst holds both the membranes and nerve roots of the spinal cord and, often, the cord itself. Or there may be a fully exposed section of the spinal cord and nerves without a cyst. Affected babies are at high risk of infection until the back is closed surgically, although antibiotic treatment may offer temporary protection. In spite of surgery, affected babies have some degree of leg paralysis and bladder- and bowel-control problems. In general, the higher the cyst on the back, the more severe the paralysis.
The causes of spina bifida are not completely understood. Scientists believe that both genetic and environmental factors act together to cause this and other NTDs. However, 95 percent of babies with spina bifida and other NTDs are born to parents with no family history of these disorders (2).
Anyone can have a baby with spina bifida. However, couples who have already had a baby with spina bifida or another NTD have an increased risk of having another affected baby. A couple with one child with spina bifida usually has about a 4 percent chance of having another affected baby, and a couple with two affected children has about a 10 percent chance of having another affected baby (2). Similarly, when one parent has spina bifida, there is about a 4 percent chance of passing the disorder on to the baby (2). Couples who have had an affected baby or have a family history of NTDs should consult a genetic counselor to discuss risks to their future children.
In most cases, spina bifida occurs by itself. However, sometimes spina bifida occurs as part of a syndrome with other birth defects. In these cases, recurrence risks in another pregnancy may vary widely.
Women with certain health conditions are at increased risk of having a baby with spina bifida. These conditions include (2,3):
- Poorly controlled diabetes
- Treatment with certain anti-seizure medications
Women with these conditions should consult their health care provider before pregnancy about steps they can take to reduce their risk of having a baby with spina bifida. For example, they can achieve a healthy weight before pregnancy, control their diabetes, change anti-seizure medications and take folic acid (see below).
Spina bifida and other NTDs occur more commonly in some ethnic groups than others. For example, NTDs are more common in Hispanics and Caucasians, and less common among Ashkenazi Jews, most Asian ethnic groups and African-Americans (2).
- Occulta: This condition usually requires no treatment. Most individuals don’t know they are affected, unless the defect is diagnosed during an X-ray for some other reason. Occasionally newborns are diagnosed with this form of spina bifida if they have a dimple or other marking on their back. In some cases, these babies may need to be evaluated for spinal cord abnormalities that could eventually result in complications, such as weakness or numbness in the legs and bladder problems. Occasionally surgery is recommended to prevent these problems.
- Meningocele: This defect is repaired surgically, and affected babies usually have no paralysis.
- Myelomeningocele: This form of spina bifida usually requires surgery within 24 to 48 hours after birth (2). Doctors surgically tuck the exposed nerves and spinal cord back inside the spinal canal and cover them with muscle and skin. Prompt surgery helps prevent additional nerve damage and infection. However, nerve damage that already has occurred cannot be reversed. Soon after surgery, a physical therapist teaches parents how to exercise their baby’s legs and feet to prepare for walking with leg braces and crutches. Many children with a defect in the lower spine can walk with or without these devices, although most children with a defect high in the spine require a wheelchair.
Common medical problems include:
- Hydrocephalus: About 70 to 90 percent of children with myelomeningocele develop hydrocephalus, a build-up of fluid in and around the brain(4). Cerebrospinal fluid cushions and protects the brain and spinal cord. When the fluid is unable to circulate normally, it collects in and around the brain, causing the head to be enlarged. Without treatment, hydrocephalus can cause brain damage and intellectual disabilities.
Doctors usually treat hydrocephalus by surgically inserting a tube called a shunt that drains the excess fluid. The shunt runs under the skin into the chest or abdomen, and the fluid passes harmlessly into the child’s body. A newer surgical procedure called endoscopic third ventriculostomy creates a new pathway for draining cerebrospinal fluid. This procedure may be recommended for some children older than 6 months, including some who experience shunt malfunctions(5).
- Chiari II malformation: Nearly all children with myelomeningocele have an abnormal change in the position of the brain. The lower part of the brain is located farther down than normal and is partly displaced into the upper part of the spinal canal. This can block the flow of cerebrospinal fluid and contribute to hydrocephalus. In most cases, affected children have no other symptoms. But a small number develop serious problems, such as breathing and swallowing difficulties and upper body weakness. In these cases, doctors may recommend surgery to relieve pressure on the brain.
- Tethered spinal cord: Most children with myelomeningocele, and a small number with meningocele or spina bifida occulta, have a tethered spinal cord. This means that the spinal cord does not slide up and down with movement as it should, because it is held in place by surrounding tissue. Some children have no symptoms, but others develop leg weakness, worsening leg function, scoliosis (curvature of the spine), pain in the back or legs, and changes in bladder function. Doctors usually recommend surgery to release the spinal cord from surrounding tissue. After surgery, a child should return to his usual level of functioning.
- Urinary tract disorders: Because of nerve damage, individuals with myelomeningocele often have problems emptying the bladder completely. This can lead to urinary tract infections and kidney damage. A technique called intermittent catheterization, in which the parent or child inserts a plastic tube into the bladder several times a day, is often helpful. Children with spina bifida should have regular care by a urologist (a doctor who specializes in urinary tract problems) to help prevent urinary tract problems.
- Latex allergy: According to the Spina Bifida Association (SBA), many children with myelomeningocele are allergic to latex (natural rubber), possibly due to repeated exposures during surgeries and medical procedures (4). Symptoms include watery eyes, wheezing, hives, rash and even life-threatening breathing problems. Doctors should consider using nonlatex gloves and equipment during procedures on individuals with spina bifida. Affected individuals and their families should avoid latex items often found in the home and community, such as most baby bottle nipples, pacifiers and balloons. A list of safe and unsafe items is available from the Spina Bifida Association.
- Learning disabilities: At least 80 percent of children with myelomeningocele have normal intelligence (4). However, some have learning problems.
- Other conditions: Some individuals with myelomeningocele have additional physical and psychological problems, such as obesity, digestive tract disorders, depression and sexual issues. With treatment, children with spina bifida usually can become active individuals. Most live normal or near-normal life spans (6).
A B-vitamin called folic acid can help prevent spina bifida and other NTDs. Studies show that if all women in the United States took the recommended amount of folic acid before and during early pregnancy, up to 70 percent of NTDs could be prevented(1). It is important for a woman to have enough folic acid in her system before pregnancy and during the early weeks of pregnancy, before the neural tube closes.
The March of Dimes recommends that all women of childbearing age take a multivitamin with 400 micrograms of folic acid every day before pregnancy and during early pregnancy. However, a woman should not take more than 1,000 micrograms (or 1 milligram) without her provider’s advice.
Healthy eating includes eating foods that are fortified with folic acid and foods that contain folate, the natural form of folic acid that is found in foods. Many grain products in the United States are fortified with folic acid. This means that a synthetic (manufactured) form of folic acid is added to them. Enriched flour, rice, pasta, bread and cereals are examples of fortified grain products. (A woman can check the label to see if a product is enriched.) Folate-rich foods include leafy green vegetables, beans and orange juice.
Women who already have had a baby with spina bifida or another NTD, as well as women who have spina bifida, diabetes or seizure disorders, should consult their health care provider before another pregnancy about the amount of folic acid to take. Studies have shown that taking a ten-fold larger dose of folic acid daily (4 milligrams), beginning at least 1 month before pregnancy and in the first trimester of pregnancy, reduces the risk of having another affected pregnancy by about 70 percent (2,7).
Health care providers routinely offer pregnant women screening tests to help identify fetuses at increased risk of spina bifida. These screening tests include a blood test called the quad screen and an ultrasound. The blood test measures the levels of four substances in the mother’s blood to identify pregnancies at higher-than-average risk of spina bifida and other NTDs, as well as Down syndrome and certain related birth defects.
If the screening test suggests an increased risk of spina bifida, the health care provider may recommend additional tests that are accurate in detecting severe spina bifida. The tests are a detailed ultrasound of the fetal spine and amniocentesis. A detailed ultrasound can help determine the seriousness of spina bifida and whether certain complications are present. In amniocentesis, the doctor inserts a needle into the woman’s uterus to take a small sample of amniotic fluid. The fluid is sent to a lab to measure levels of alpha-fetoprotein (AFP) in the fluid. An abnormal amount of the protein in the fluid is associated with spina bifida.
When spina bifida is diagnosed early in pregnancy, women can consult with their health care provider to learn more about the disorder and to consider their options. For example, they can plan for delivery in a specially equipped medical center so that the baby can have any necessary surgery or treatment soon after birth.
Parents and doctors also can discuss whether a vaginal or cesarean delivery would be best for their baby. Fetuses with myelomeningocele are more likely than other babies to be in a breech (feet-first) position. A cesarean delivery is generally recommended for these babies (2). Some doctors may recommend a cesarean delivery for babies with myelomeningocle who are in a normal head-first position, especially if they have a large cyst (3,8). One study found that a planned cesarean delivery can reduce the severity of paralysis in babies with myelomeningocele; however, several studies found no reduction in paralysis in babies delivered by cesarean (2,8,9).
More than 400 babies have undergone experimental prenatal surgery to repair myelomeningocele before birth( 10). This approach is based on the idea that early repair (between the 19th and 25th weeks of pregnancy) may help prevent damage to exposed spinal nerve tissue in the womb and reduce paralysis and other complications. Preliminary results suggest that children who have prenatal surgery have improvements in the Chiari malformation and may need a hydrocephalus shunt less frequently, but their bladder and bowel function do not appear to be improved (2,3). One study found better-than-expected walking ability in toddlers, but other studies did not (3,11). This procedure poses surgery-related risks to mother and baby and puts the baby at high risk of premature delivery (before 37 weeks of pregnancy). Prematurity increases the risk of health problems during the newborn period and lasting disabilities. Doctors do not yet know whether the benefits of prenatal surgery outweigh these risks.
To find out whether prenatal or postnatal surgery is more effective, the National Institute of Child Health and Human Development (NICHD), a part of the National Institutes of Health (NIH), is conducting a study to compare the results of both types of surgery in 200 babies with myelomeningocele( 6). Half of the babies undergo surgery before birth, while the other half have surgery shortly after birth. The surgery is being carried out at three major medical centers: Children’s Hospital of Philadelphia, the University of California at San Francisco and Vanderbilt University Medical Center in Nashville. More about this research is available at the study Web site or (866)-ASK-MOMS (866-275-6667).
Several March of Dimes grantees are searching for genes that may contribute to spina bifida and other NTDs to develop new ways to prevent these disorders. Others are seeking a better understanding of how folic acid prevents NTDs, to make this treatment even more effective.
The March of Dimes is a member of the National Council on Folic Acid, an alliance of organizations working to promote the benefits and consumption of folic acid.
More information is available from:
- Centers for Disease Control and Prevention (CDC). Spina Bifida. Created 3/11/09.
- American College of Obstetricians and Gynecologists (ACOG). Neural Tube Defects. ACOG Practice Bulletin, number 44, July 2003 (reaffirmed 2008).
- Fichter, M.A., et al. Fetal Spina Bifida Repair – Current Trends and Prospects of Intrauterine Neurosurgery. Fetal Diagnosis and Therapy, 2008, volume 23, pages 271-286. \
- Spina Bifida Association. About Spina Bifida, accessed 6/12/09.
- Jallo, G.I., et al. Endoscopic Third Ventriculostomy. Neurosurg Focus, volume 19, number 6, E11, December 2005.
- Management of Myelomeningocele Study. About Spina Bifida, accessed 6/9/09.
- Centers for Disease Control and Prevention (CDC). Folic Acid. Updated 3/31/09.
- Hamrick, S.E.G. Cesarean Delivery and Its Impact on the Anomalous Infant. Clinics in Perinatology, volume 35, 2008, pages 395-406.
- Luthy, D.A., et al. Cesarean Section Before the Onset of Labor and Subsequent Motor Function in Infants with Meningomyelocele Diagnosed Antenatally. New England Journal of Medicine, volume 324, 1991, pages 662-666.
- Sutton, L.N. Fetal Surgery for Neural Tube Defects. Best Pract Res Clin Obstet Gynaecol, February 2008, volume 22, number 1, pages 175-188.
- Danzer, E., et al. Lower Extremity Neuromotor Function and Short-Term Ambulatory Potential Following In Utero Myelomeningocele Surgery. Fetal Diagnosis and Therapy, 2009, volume 25, pages 47-53.
Last reviewed August 2009
Most common questions
Can dad's exposure to chemicals harm his future kids?
Dad's exposure to harmful chemicals and substances before conception or during his partner's pregnancy can affect his children. Harmful exposures can include drugs (prescription, over-the-counter and illegal drugs), alcohol, cigarettes, cigarette smoke, chemotherapy and radiation. They also include exposure to lead, mercury and pesticides.
Unlike mom's exposures, dad's exposures do not appear to cause birth defects. They can, however, damage a man's sperm quality, causing fertility problems and miscarriage. Some exposures may cause genetic changes in sperm that may increase the risk of childhood cancer. Cancer treatments, like chemotherapy and radiation, can seriously alter sperm, at least for a few months post treatment. Some men choose to bank their sperm to preserve its integrity before they receive treatment. If you have a question about a specific exposure, contact the Organization of Teratology Information Specialists at www.otispregnancy.org.
Can Rh factor affect my baby?
The Rh factor may be a problem if mom is Rh-negative but dad is Rh-positive. If dad is Rh-negative, there is no risk.
If your baby gets her Rh-positive factor from dad, your body may believe that your baby's red blood cells are foreign elements attacking you. Your body may make antibodies to fight them. This is called sensitization.
If you're Rh-negative, you can get shots of Rh immune globulin (RhIg) to stop your body from attacking your baby. It's best to get these shots at 28 weeks of pregnancy and again within 72 hours of giving birth if a blood test shows that your baby is Rh-positive. You won't need anymore shots after giving birth if your baby is Rh-negative. You should also get a shot after certain pregnancy exams like an amniocentesis, a chorionic villus sampling or an external cephalic version (when your provider tries to turn a breech-position baby head down before labor). You'll also want to get the shot if you have a miscarriage, an ectopic pregnancy or suffer abdominal trauma.
Does cleft lip or cleft palate cause dental problems?
A cleft lip or cleft palate that extends into the upper gums (where top teeth develop) can cause your baby to have certain dental problems, including:
- Missing teeth
- Too many teeth
- Oddly shaped teeth
- Teeth that are out of position around the cleft
Every baby with a cleft lip or palate should get regular dental checkups by a dentist with experience taking care of children with oral clefts. Dental problems caused by cleft lip or palate usually can be fixed. If needed, your baby can get ongoing care by a team of experts, including:
- A dentist
- An orthodontist to move teeth using braces
- An oral surgeon to reposition parts of the upper jaw, if needed, and to fix the cleft
See also: Cleft lip and cleft palate
Does cleft lip or cleft palate cause ear problems?
Cleft lip does not cause ear problems.
Babies with cleft palate, however, are more likely than other babies to have ear infections and, in some cases, hearing loss. This is because cleft palate can cause fluid to build up in your baby’s middle ear. The fluid can become infected and cause fever and earache. If fluid keeps building up with or without infection, it can cause mild to moderate hearing loss.
Without treatment , hearing loss can affect your baby’s language development and may become permanent.
With the right care, this kind of hearing loss is usually temporary. Your baby’s provider may recommend:
- Having your baby’s ears checked regularly for fluid buildup
- Medicines for treating fluid buildup and ear infections
- Ear tubes if your baby has fluid in his ears over and over again. Ear tubes are tiny tubes that are inserted into the eardrum to drain the fluid and help prevent infections.
See also: Cleft lip and cleft palate
Does cleft lip or cleft palate cause problems with breastfeeding?
Babies with only a cleft lip usually don’t have trouble breastfeeding. Most of the time, they can breastfeed just fine. But they may need some extra time to get started.
Babies with cleft lip and palate or with isolated cleft palate can have:
- Trouble sucking strong enough to draw milk through a nipple
- Problems with gagging or choking
- Problems with milk coming through the nose while feeding
Most babies with cleft palate can’t feed from the breast. If your baby has cleft palate, he can still get the health benefits of breastfeeding if you feed him breast milk from a bottle. Your provider can show you how to express (pump) milk from your breasts and store breast milk.
Your baby’s provider can help you start good breastfeeding habits right after your baby is born. She may recommend:
- Special nipples and bottles that can make feeding breast milk from a bottle easier
- An obturator. This is a small plastic plate that fits into the roof of your baby’s mouth and covers the cleft opening during feeding.
See also: Cleft lip and cleft palate, Breastfeeding
Does cleft lip or cleft palate cause speech problems?
Children with cleft lip generally have normal speech. Children with cleft lip and palate or isolated cleft palate may:
- Develop speech more slowly
- Have a nasal sound when speaking
- Have trouble making certain sounds
Most children can develop normal speech after having cleft palate repair. However, some children may need speech therapy to help develop normal speech.
See also: Cleft lip and cleft palate
What are choroid plexus cysts?
The choroid plexus is the area of the brain that produces the fluid that surrounds the brain and spinal cord. This is not an area of the brain that involves learning or thinking. Occasionally, one or more cysts can form in the choroid plexus. These cysts are made of blood vessels and tissue. They do not cause intellectual disabilities or learning problems. Using ultrasound, a health care provider can see these cysts in about 1 in 120 pregnancies at 15 to 20 weeks gestation. Most disappear during pregnancy or within several months after birth and are no risk to the baby. They aren't a problem by themselves. But if screening tests show other signs of risk, they may indicate a possible genetic defect. In this case, testing with higher-level ultrasound and/or amniocentesis may be recommended to confirm or rule out serious problems.
What if I didn't take folic acid before pregnancy?
If you didn’t take folic acid before getting pregnant, it doesn't necessarily mean that your baby will be born with birth defects. If women of childbearing age take 400 micrograms of folic acid every day before and during early pregnancy, it may help reduce their baby’s risk for birth defects of the brain and spin called neural tube defects (NTDs). But it only works if you take it before getting pregnant and during the first few weeks of pregnancy, often before you may even know you’re pregnant.
Because nearly half of all pregnancies in the United States are unplanned, it's important that all women of childbearing age (even if they're not trying to get pregnant) get at least 400 micrograms of folic acid every day. Take a multivitamin with folic acid before pregnancy. During pregnancy, switch to a prenatal vitamin, which should have 600 micrograms of folic acid.
Last reviewed November 2012