What is spina bifida?
Spina bifida is a condition in which there is abnormal development of the back bones,
spinal cord, surrounding nerves, and the fluid-filled sac that surrounds the spinal
cord. This neurological condition can cause a portion of the spinal cord and the surrounding
structures to develop outside, instead of inside, the body. The defect can occur anywhere
along the spine.
What are the types of spina bifida?
The types of spina bifida include the following:
Spina bifida occulta. A mild form of spina bifida in which the spinal cord and the surrounding structures
remain inside the baby, but the back bones in the lower back area fail to form normally.
There may be a hairy patch, dimple, or birthmark over the area of the defect. Other
times, there may be no abnormalities in the area.
Meningocele. A moderate form of spina bifida in which a fluid-filled sac is visible outside of
the back area. The sac does not contain the spinal cord or nerves.
Myelomeningocele. A severe form of spina bifida in which the spinal cord and nerves develop outside
of the body and are contained in a fluid-filled sac that is visible outside of the
back area. These babies typically have weakness and loss of sensation below the defect.
Problems with bowel and bladder function are also common. A majority of babies with
myelomeningocele will also have hydrocephalus, a condition that causes the fluid inside
of the head to build up, causing pressure inside of the head to increase and the skull
bones to expand to a larger than normal size.
What causes spina bifida?
Spina bifida is a type of neural tube defect. Neural tube defects, including spina
bifida (open spine) and anencephaly (open skull), are seen in 7 out of 10,000 live
births in the U.S.
During pregnancy, the human brain and spine begin as a flat plate of cells, which
rolls into a tube, called the neural tube. If all or part of the neural tube fails
to close, leaving an opening, this is known as an open neural tube defect (or ONTD).
This opening may be left exposed or covered with bone or skin.
Anencephaly and spina bifida are the most common types of ONTD, while encephalocele
(in which there is a protrusion of the brain or its coverings through the skull) is
much rarer. Anencephaly occurs when the neural tube fails to close at the base of
the skull, while spina bifida occurs when the neural tube fails to close somewhere
along the spine.
In the vast majority of cases, an ONTD occurs without a prior family history of these
defects. ONTDs result from a combination of genes inherited from both parents, coupled
with environmental factors. Many factors, both genetic and environmental, contribute
to their occurrence.
Some of the environmental factors that may contribute to ONTDs include obesity, uncontrolled
diabetes in the mother, and certain prescription medications. According to the CDC,
the occurrence rate of ONTDs can vary from state to state and from country to country.
Once a child with an ONTD has been born in the family, the chance for an ONTD to occur
again is increased to 4%. It is important to understand that the type of neural tube
defect can differ the second time. For example, one baby could be born with anencephaly,
while a second baby could have spina bifida (not anencephaly).
Prevention of neural tube defects
Because the neural tube closes 28 to 32 days after conception and before many women
are aware they are pregnant, normal development of the brain and spinal cord may be
affected during these first 3 to 8 weeks of pregnancy by the following:
Exposure to hazardous chemicals and other substances
Lack of proper vitamins (folic acid) and nutrients in the diet
Prescription drug and alcohol consumption
Although many factors related to the development of spina bifida, research has found
that folic acid (vitamin B-9), a nutrient found in some green, leafy vegetables, nuts,
beans, citrus fruits, and fortified breakfast cereals, can help reduce the risk of
neural tube defects. For this reason, the American College of Medical Genetics and
the CDC recommend that all women of childbearing age take a multivitamin containing folic acid. Folic acid is
in prenatal vitamins. Supplementation early in pregnancy is thought to be most important.
If a couple has had a previous child with an ONTD, a larger amount of folic acid is
recommended and can be prescribed by the woman's doctor or health care provider. This
allows the woman to take it for 1 to 2 months prior to conception, and throughout
the first trimester of pregnancy, to reduce the risk of another child with ONTD. Current
research is focused on looking at how genes control the formation of the neural tube.
Understanding this will assist in the prevention of neural tube defects.
Additional risk factors include:
Maternal age. Spina bifida is more commonly seen in teenage mothers.
History of miscarriage
Birth order. First-born infants are at higher risk.
Socioeconomic status. Children born into lower socioeconomic families are at higher risk for developing
spina bifida. It is thought that a poor diet, lacking essential vitamins and minerals,
may be a contributing factor.
In recent years, pioneer surgeons have developed an experimental technique for performing
surgery prenatally to correct this condition before birth.
What are the symptoms of spina bifida?
The following are the most common symptoms of spina bifida. However, each baby may
experience symptoms differently. Symptoms may include:
Abnormal appearance of the baby's back, varying from a small, hairy patch or a dimple
or birthmark, to a sac-like protrusion that is found along the back bone area.
Bowel and bladder problems (for example, constipation or incontinence)
Loss of feeling below the area of the lesion, especially in babies born with a meningocele
Inability to move the lower legs (paralysis)
The baby may also have other problems related to spina bifida that include the following:
Hydrocephalus (increased fluid and pressure in the head area; occurs in about 70%
to 90% of cases)
Orthopedic (bone) problems
Lower than normal intelligence level
The symptoms of spina bifida may look like other conditions or medical problems. Always
consult your baby's doctor for a diagnosis.
How is spina bifida diagnosed?
Diagnostic tests can be performed during pregnancy to evaluate the fetus for spina
bifida. The tests include the following:
Blood tests. The American College of Obstetrics and Gynecology recommends that a blood test be
offered between 16 and 18 weeks to all women who are pregnant who have not previously
had a child with an ONTD and who do not have a family history of ONTD. This blood
test measures alpha-fetoprotein (AFP) levels and other biochemical markers in the
mother's blood to determine whether her pregnancy is at increased risk for an ONTD.
AFP is a protein normally produced by the fetus that crosses the placenta into the
mother's blood. Generally, if a fetus has an ONTD, the alpha-fetoprotein level in
the mother's blood will be increased. Although this test does not tell for certain
whether a fetus has an ONTD, it will determine which pregnancies are at greater risk,
so that additional testing may be performed.
Prenatal ultrasound (also called sonography). A diagnostic imaging technique that uses high-frequency sound waves and a computer
to create images of blood vessels, tissues, and organs. Ultrasounds are used to view
internal organs as they function, and to assess blood flow through various vessels.
Prenatal ultrasound may be able to detect an ONTD, and may be used to examine other
organs and body systems of the fetus.
Amniocentesis. A procedure that involves inserting a long, thin needle through the mother's abdomen
into the amniotic sac to withdraw a small sample of the amniotic fluid for examination.
The fluid is then tested to determine the presence of alpha-fetoprotein, which occurs
with an open neural tube defect. Small or closed defects may not be picked up by this
Management of spina bifida
The primary goal of managing spina bifida is to prevent infection and to preserve
the spinal cord and nerves that are exposed outside of the body. Specific management
of spina bifida will be determined by your baby's doctor based on:
Your baby's gestational age, overall health, and medical history
The extent and type of spina bifida
Your baby's tolerance for specific medications, procedures, or therapies
Expectations for the course of spina bifida
Your opinion or preference
A cesarean delivery is often done to decrease the risk of damage to the spinal cord
that may occur during a vaginal delivery. Babies born with a meningocele or a myelomeningocele
usually require care in the neonatal intensive care unit (NICU) for evaluation and
for surgery to close the defect. Surgery can help manage the problems, but it cannot
restore muscle function or sensation to a normal state. Surgical interventions may
be needed for the following:
Repair and closure of the lesion
Treatment of hydrocephalus
Orthopedic problems. Orthopedic problems may include curvatures in the back, hip dislocations, ankle and
foot deformities, and contracted muscles. Babies and children with spina bifida are
also very susceptible to breaking their bones since their bones may be weaker than
Bowel and bladder problems. Bowel and bladder problems may require surgery to improve function in elimination,
for incontinence, constipation, or when the bladder does not empty completely.
Following surgery, you will receive instructions on caring for your baby at home.
Education may include the following:
Examining the skin, especially over bony areas, such as the elbows, buttocks, back
of the thighs, heel, and foot areas. Recommendations may include changing your baby's
position frequently to prevent skin breakdown and pressure sores.
Promoting bowel and bladder function
Ways to feed you baby and monitor your baby's nutrition
Promoting activity and mobility
Encouraging age-appropriate growth and development
Not all babies will require surgical repair of spina bifida. Nonsurgical management
of spina bifida may include the following:
Positioning aids (used to help the child sit, lie, or stand)
Braces and splints (used to prevent deformity, promote support or protection)
Babies with spina bifida are at high risk for developing a latex allergy due to exposure
to latex from multiple medical and surgical procedures. Precautions are taken by the
health care team to reduce the baby's exposure to products that contain latex. Your
baby's health care providers can help you identify products that contain latex and
also find products that are latex-free.
Spina bifida is a lifelong condition that is not curable. Management often focuses
on preventing or minimizing deformities and maximizing the child's capabilities at
home and in the community. Positive reinforcement will encourage the child to strengthen
his or her self-esteem and promote as much independence as possible. Aggressive physical
and occupational rehabilitation, as well as appropriate educational interventions
through a multidisciplinary approach, can maximize the child's functional capacity.
The full extent of the problem is usually not completely understood immediately after
birth, but may be revealed as the child grows and develops.
Genetic counseling may be recommended by your doctor to discuss the risk of recurrence
in a future pregnancy, as well as vitamin therapy (a prescription for folic acid)
that can decrease the recurrence risk for ONTDs. Supplemental folic acid if taken
one to two months prior to conception and throughout the first trimester of pregnancy
has been found to decrease the reoccurrence of ONTDs for couples who have had a previous
child with an ONTD.