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 each year.
The types of neural tube defects include:
Spina bifida. 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 (permanent), 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 1 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). Or 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 after birth.
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 of 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 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 boys.
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. For example, a family's first baby could be born with anencephaly. A second baby could have spina bifida instead.
Other risk factors for neural tube defects include:
Mother’s age. Spina bifida is more common in teen mothers.
History of miscarriage.A woman who has had miscarriages in the past has a higher risk of having a baby with neural tube defects.
Birth order. 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 factor.
Symptoms depend on the type of ONTD. And they can occur a bit differently in each child.
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)
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
Fluid on the brain (hydrocephaly)
Weakness of arms or legs
Trouble moving, walking, reaching
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:
Blood test.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 be offered to all pregnant women.
Prenatal ultrasound.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 may 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 to reach the amniotic sac. He or she takes 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 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 keep the baby as comfortable as possible. Anencephaly most often leads to death in days or weeks. Grief counseling services are available to help parents cope with the loss of their child.
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
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 tube 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 help your child make the most of his or her capabilities. Physical and occupational rehabilitation, plus extra support in school, can help a child function as well as possible.
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, clergy, 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 your baby. Because many babies born with anencephaly may not live beyond the first few days or weeks of life, you may have to cope with your baby never coming home from the hospital.
Call the healthcare provider if your child has:
Symptoms that don’t get better, or get worse
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 factors.
Symptoms can include a bulging sac on the back of the neck or head, or a very small head.
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.