Neural Tube Defects

We know a diagnosis of a neural tube defect (NTD) in your baby can be overwhelming and scary. The experts at CHOC provide comprehensive care from testing to diagnosis and beyond. Your and your baby’s care will include specialists from many departments, including counseling, to help your family cope with a difficult diagnosis.

What Are Neural Tube Defects?

Neural tube defects (NTDs) are types of neurological disorders present at birth. The conditions are due to malformations of the spine, spinal cord and brain. The neural tube is the structure in an embryo that later becomes a baby’s spinal cord, spine, brain and skull. It starts as a flat structure but rolls together to form a tube during embryonic development. Neural tube defects occur when this structure does not close properly. These defects occur very early in pregnancy, when a baby is still just an embryo, about one month after conception.

Types of Neural Tube Defects

Spina Bifida: A spinal cord defect resulting in an abnormal formation of the back bones, spinal cord and nerves that causes a portion of the spinal cord and surrounding structure to develop outside the body. It can result in a sac-like protrusion found along the backbone. This is the most common type of NTD. In most cases, a child will need surgery after birth to fix the protrusion. Spina bifida occurs in about 7 out 10,000 live births.

Encephalocele: A hole in the skull during development that results in brain matter, fluids and covering membranes developing outside the skull. It results in a sac-like protrusion found along the head, typically on the back or near the nose. Severity depends on the size and location of the opening in the skull. Most babies will need multiple surgeries after birth to correct this very rare condition.

Anencephaly: Occurring when the neural tube does not close at the base of the skull, anencephaly causes babies to be born missing parts of their brain and skull. Babies are typically missing their forebrain, cerebrum and the bone or skin covering the remaining parts of their brain. Babies with anencephaly often do not survive in the uterus after 20 weeks of pregnancy or do not live very long after birth.

What Causes Neural Tube Defects?

NTDs can have multiple causes, including a combination of genetic and environmental factors. Environmental factors can include where you live or work, the food you eat, exposure to toxins, etc. Taking a prenatal vitamin with folic acid can help protect against NTDs.

Some risk factors for neural tube defects include:

  • A history of NTDs. 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 chance also increases if the biological father has a family history of NTDs.
  • Mother’s health. Likelihood increases if the mother has type 1 diabetes, obesity or folate deficiency.
  • Mother’s medications. Likelihood increases if the mother takes anti-epileptic meds (especially ones that contain sodium valproate or valproic acid).
  • Mother’s age. Spina bifida is more common in teen mothers.

Symptoms of Neural Tube Defects

Symptoms of neural tube defects will depend on the condition, severity and affected region.

Spina Bifida Symptoms

  • An area on the back looks abnormal like a small hairy patch, dimple, birthmark, or sac
  • No feeling below the place on the spine where the sac is located
  • Paralysis of the legs
  • Chronic constipation
  • Increased fluid and pressure in the head area (hydrocephalus)
  • Heart problems
  • Bone problems
  • Intellectual disability

Encephalocele Symptoms

  • Sac on the skull
  • Face defects
  • Hydrocephalus
  • Small head
  • Weakness of arms or legs
  • Trouble walking
  • Vision problems
  • Intellectual disability
  • Delayed growth and development
  • Seizures or epilepsy

Anencephaly Symptoms

  • No bones on back of the head
  • Missing bones on front and side of head
  • Large areas of brain missing
  • Folding of the ears
  • Cleft palate
  • Congenital heart defects

Diagnosis of Neural Tube Defects

Neural tube defects are usually diagnosed in the womb but in some cases won’t be recognized until after birth. Common fetal tests used to diagnose a neural tube defect include:

  • Prenatal Ultrasound: Using sound waves and a computer an ultrasound creates images to view the baby’s internal organs and overall development. This is used for the initial detection.
  • Anomaly Scan: An ultrasound that is focused on identifying physical problems around 18 to 20 weeks of pregnancy. This is the most accurate method for diagnosing spina bifida.
  • Fetal MRI: MRI imaging gives incredibly detailed pictures of organs, bones and tissues without using ionizing radiation (X-rays). Fetal MRI gives higher resolution information and supplements abnormalities that may have been seen on a prenatal ultrasound. It can be performed as early as 20 weeks.
  • Quad Screen: Measures 4 substances in the mother’s blood, specifically levels of alpha-fetoprotein (AFP). Other substances include human chorionic gonadotropin (hCG), estriol (uE3) and inhibin A. If the baby has a NTD, the AFP level will be higher.
  • Triple Screen: A blood test that looks for elevated levels of AFP. Other parts include testing for human chorionic gonadotropin (hCG) and estriol (uE3).
  • Maternal Serum Alpha-fetoprotein (MSAFP): A sample of blood is drawn, focusing just on AFP.
  • Amniocentesis: Looks at a sample of fluid from the amniotic sac that surrounds the baby in the uterus.

Prevention of Neural Tube Defects

Including the recommended amount of folate/folic acid in your diet can help prevent neural tube defects from developing in the early stages of your pregnancy. Because NTDs occur during embryonic development, often before most women know they are pregnant, women planning or trying to get pregnant should include folic acid in their daily diet. The recommended dose of folic acid is 400 micrograms a day. However, if you have had a previous pregnancy affected by NTD and are interested in having another baby, you should speak with a doctor about an individual dosage. Folic acid can be included in a diet via a direct supplement or by eating folate-rich foods like leafy green vegetables, fruit, dried beans and enriched breads. Individual prenatal prevention should be discussed with your OB/GYN.

Your healthcare provider may also advise genetic counseling. You can talk with a counselor about the risk of a neural tube defect in future pregnancies.

The Fetal Care Center of Southern California

If an abnormality is detected before your baby is born, our team of pediatric experts at the Fetal Care Center of Southern California can confirm your baby’s diagnosis, provide extensive condition education and counseling, and begin comprehensive treatment planning for after your baby’s birth.

Request A Consultation

Treatment of Neural Tube Defects

Specific treatment depends on the type of neural tube defect and the severity of the condition.

Spina Bifida Treatment

Treatment for spina bifida will typically include one or more surgeries to help fix the defect; however, there is no treatment for any nerve damage caused by the malformation. Many babies born with spina bifida also have hydrocephalus, which causes the head to swell from excess fluid buildup. Treatment for hydrocephalus includes insertion of a shunt to help drain the fluid and release the pressure inside the cranium. Additional therapy may also be needed for walking or bowel and bladder management. Most complications from spina bifida can be treated or managed to improve quality of life.

Other condition management includes rehabilitation, positioning aids, branches and splints or medical management.

Learn more about treatment at CHOC for Spina Bifida.

Encephalocele Treatment

The size, location and type of encephalocele will impact a baby’s survival of this condition, their quality of life after birth and the appropriate treatment for their condition. Surgery will be done to place the protruding sac of the brain and membranes back into the skull and close the opening. In some cases, multiple surgeries may be needed due to the location and region affected. While surgical treatment for the opening is typical, any neurological problems caused by this condition are permanent.

Learn more about treatment at CHOC for Encephalocele.

Anencephaly Treatment

There is currently no standard treatment for anencephaly. Treatment at CHOC is supportive and meant to keep babies as comfortable as possible during their time at the hospital. Babies with this condition usually live for only a few days or weeks after birth. Bereavement counseling is available at CHOC to support parents in coping.

Long-term Effects of Neural Tube Defects

The long-term effects of neural tube defects depend on the specifics of a baby’s condition. Any nerve damage and/or loss of function that are present at birth and caused by the NTDs will likely be permanent. For spina bifida, some cases have no lasting effects, while others may have difficulty walking or abnormal bladder or bowel dysfunction. With encephalocele, children can experience neurological problems, development delays, seizures or balance and coordination problems. Your child’s providers will work to keep long-term effects to a minimum. They will also work to help your child make the most of their capabilities. Physical and occupational rehabilitation, plus extra support in school, can help a child reach their full potential.

Michelle’s Journey With Encephalocele

When Michelle’s mom was 21 weeks pregnant, she received news that Michelle’s head was measuring too small in the womb. A visit to a high-risk maternal-fetal specialist would result in diagnoses of encephalocele and microcephaly, a rare condition where a child’s brain does not fully develop. The family sought care at CHOC after Michelle’s birth, including surgery and ongoing therapy to help Michelle thrive.

Read Michelle's Story