Open neural tube defects (ONTDs)
are problems with the way the brain, spinal cord, or spine forms while a baby is growing
in the mother’s uterus. These problems occur in about 1 in every 1,500 newborn babies
The types of neural tube defects include:
This is when the spine doesn’t grow normally over the spinal
cord. Babies born with spina bifida may have minor or short-term problems. Or they
may have lasting, serious physical problems. These may include paralysis, lack of
bowel and bladder control, club feet, a buildup of spinal fluid in the head
(hydrocephaly), and intellectual disability. In most cases, a child may need one or
more surgeries after birth. This is the most common kind of ONTD.
Anencephaly. This defect is when part of the brain and skull don’t
form. It occurs when the neural tube doesn’t close at the base of the skull. Babies
with anencephaly often die in the uterus after 20 weeks of pregnancy (stillborn).
they only live for a very short time after birth.
Encephalocele. This is a very rare condition. With this defect, the
brain or its coverings poke through the skull. This can occur anywhere from the
forehead to the lower back of the skull. But it may also occur in the front of the
skull, near the nose and sinuses. In most cases, a child may need multiple surgeries
During pregnancy, the brain and
spine begin as a flat plate of cells. This plate rolls into a tube, called the neural
tube. The tube is completely formed 28 to 32 days after conception. If all or part
the neural tube fails to close, this leaves an opening. The opening is called an open
neural tube defect. The opening in the tube may be left exposed or it may be covered
with bone or skin.
Neural tube defects are caused by genes passed on from both parents and from environmental
factors. Some of these factors include obesity, uncontrolled diabetes in the mother,
and some prescription medicines. In most cases, a child with a neural tube defect
has no family history of this problem. ONTDs happen 5 times more often in girls than
Once a child with a neural tube
defect has been born in the family, the chance that this problem will happen in another
child rises to 1 in 25. The type of neural tube defect can differ the second time.
example, a family’s first baby could be born with anencephaly. A second baby could
spina bifida instead.
Other risk factors for neural tube defects include:
Spina bifida is more common in teen mothers.
A woman who has had miscarriages in the past has a higher risk of having a baby
with neural tube defects.
First-born babies are at higher risk.
Socioeconomic status. Children born into lower socioeconomic families
are at higher risk for spina bifida. Researchers think that poor diet may be a
Symptoms depend on the type of ONTD. And they can occur a bit differently in each
Symptoms of spina bifida can include:
- Area on the back that looks abnormal, such as a small hairy patch, dimple, or birthmark,
or a pouch-like bulge (sac)
- No feeling below the place on the spine where the sac is
- No ability to move the legs (paralysis)
- Constipation or incontinence
The baby may also have other problems such as:
- Increased fluid and pressure in the head area (hydrocephalus)
- Heart problems
- Bone problems
- Intellectual disability
Symptoms of anencephaly can include:
- No bones on the back of the head
- Missing bones on the front and sides of the head
- Large areas of brain missing
- Folding of the ears
- Split in the roof of the mouth (cleft palate)
- Congenital heart defects
Symptoms of encephalocele can include:
- Bulging sac at back of skull
- Face defects
- Fluid on the brain (hydrocephaly)
- Small head
- Weakness of arms or legs
- Trouble moving, walking, reaching
- Intellectual disability
- Vision problems
- Delayed growth and development
The signs and symptoms of open neural tube defects can be like other health conditions.
Make sure your child sees his or her healthcare provider for a diagnosis.
ONTDs can be diagnosed before birth with tests that include:
A test called a quad screen measures 4 substances in the mother’s blood. This
can see if there is an increased risk for neural tube defects and other problems.
This test is done between 16 and 18 weeks of pregnancy. It measures levels of
alpha-fetoprotein (AFP) and other things in the blood. AFP is a protein made by the
baby growing in the uterus. If a baby has an open neural tube defect, the AFP level
in the mother’s blood will be higher than normal. The test isn’t conclusive. This
means it can’t prove that your baby has an open neural tube defect. But it can show
if your baby is at risk for an ONTD. The test can show if you need more testing. The
American College of Obstetrics and Gynecology (ACOG) advises that this blood test
offered to all pregnant women.
This imaging test uses high-frequency sound waves and a computer to make images
of blood vessels, tissues, and organs. Ultrasounds let healthcare providers see the
internal organs as they function. They also show blood flow through blood vessels.
Prenatal ultrasound may be able to find an open neural tube defect. Your provider
also use ultrasound to look at some of the baby’s other organs and body systems.
Amniocentesis. This test looks at a small sample of the fluid that
surrounds the baby in the uterus. The healthcare provider uses a long, thin needle
reach the amniotic sac. They take the sample of fluid and checks it for AFP. The test
may not be able to find small or closed defects.
After birth, a healthcare provider makes a diagnosis with a physical exam.
If your baby has an ONTD, you may need to have a cesarean section to deliver your
baby. This is often done to lower the risk for damage to the spinal cord that may
occur during a vaginal delivery.
If your child has spina bifida or encephalocele, he or she may need surgery to:
- Fix and close the defect
- Treat hydrocephalus
- Treat bone (orthopedic) problems
- Repair bowel and bladder problems
A baby may also need:
- Positioning aids that help the child sit, lie, or stand
- Braces and splints that help prevent deformity and give support or protection to areas
of the body
Talk with your child’s healthcare
providers about the risks, benefits, and possible side effects of all treatments.
There is no cure or standard
treatment for anencephaly. Treatment is supportive. This means efforts are made to
the baby as comfortable as possible. Anencephaly most often leads to death in days
Babies with spina bifida are at high risk of developing a latex allergy. This is because
they are exposed to latex during the many medical and surgical procedures they need.
Your baby’s healthcare team will do their best to limit how much latex your baby is
exposed to. Your baby’s healthcare providers can help you find out which products
contain latex and also find products that are latex-free.
Up to 3 in 4 babies with anencephaly are stillborn. Anencephaly most often leads to
death in days or weeks.
The neural tube closes 28 to 32 days after a baby is conceived. This is before many
women know that they are pregnant. Normal development of the brain and spinal cord
may be affected during these first 3 to 8 weeks of pregnancy by:
- Not getting enough vitamins such as folic acid and other nutrients
- Using prescription medicine or alcohol
- Being around hazardous chemicals and other substances
- Genetic problems
Folic acid is in prenatal vitamins. Getting this vitamin early in pregnancy is important
to prevent an ONTD. Researchers have found that a woman who gets enough folic acid
(vitamin B-9) can help lower the risk for neural tube defects. Folic acid is found
in some leafy green vegetables, nuts, beans, citrus fruits, and fortified breakfast
cereals. Experts recommend that all women of childbearing age take a daily multivitamin
containing 400 to 800 micrograms of folic acid.
If you have had a child with a neural tube defect, your healthcare provider may recommend
taking a larger amount of folic acid before your next pregnancy. Your provider may
tell you to take this extra amount for 1 to 2 months before conception and then through
the first trimester.
Your healthcare provider may also
advise genetic counseling. You can talk with a counselor about the risk of a neural
defect in a future pregnancy. Also talk with your provider about getting a prescription
for folic acid to lower the risk for another open neural tube defect.
Your child’s healthcare providers
will work to prevent deformities or keep them to a minimum. They will also work to
your child make the most of their capabilities. Physical and occupational
rehabilitation, plus extra support in school, can help a child function as well as
If your baby is born with an ONTD, there are things you can do to take care of yourself
and your baby:
- Keep all appointments with your baby’s healthcare provider.
- Talk with your baby’s healthcare
provider about other providers who will be part of your child’s care. Your child may
get care from a multidisciplinary team that may include counselors, social workers,
genetic counselors, and physical or occupational therapists. Your child’s care team
will depend on your baby’s condition.
- Call your baby’s healthcare provider if you are concerned about your baby’s symptoms.
- Consider genetic testing and counseling to understand your risk.
- Tell others about your baby’s condition. Work with your child’s healthcare provider
to develop a treatment plan.
- Ask for support from local community services, such as your faith community, and organizations
that specialize in birth defects, such as the March of Dimes.
A diagnosis of anencephaly can be
overwhelming and upsetting. You will face difficult decisions about how to care for
baby. Many babies born with anencephaly may not live beyond the first few days or
of life. Grief counseling may help you cope with this loss.
Call the healthcare provider if your child has:
- Symptoms that don’t get better, or get worse
- New symptoms
- Open neural tube defects (ONTDs) are problems with the way the brain, spinal cord,
or spine forms while a baby is growing in the womb.
- The types of neural tube defects include spina bifida, anencephaly, and encephalocele.
Treatment for an ONTD depends on the type of defect your child has.
- Neural tube defects are caused by genes passed on from both parents and from environmental
- Symptoms can include a bulging sac on the back of the neck or head, or a very small
- Experts recommend that all women of childbearing age take a daily multivitamin containing
400 to 800 micrograms of folic acid. Getting this vitamin early in pregnancy is important
to prevent an ONTD.
- ONTDs can be diagnosed before birth with tests that include a blood test, prenatal
ultrasound, or amniocentesis.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child.
Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose
for that visit.
- Know how you can contact your child’s provider after office hours. This is important
if your child becomes ill and you have questions or need advice.