A health condition that affects infants within the first months of life and causes defects of the brain, spine, or spinal cord is called Neural Tube Defects (NTDs). Commonly, these defects are linked with folate (folic acid) deficiency before and during pregnancy. Thus, you should make sure you have enough folate before and during pregnancy, and if not, you should administer supplements and make dietary changes.
The most common NTDs are spina bifida and anencephaly. In normal circumstances, both sides of the fetus’s spine (also called the backbone) join together, which allows protection to the spinal cord, nerves, and meninges (tissue that covers the spinal cord). In this case, the developing brain and spine are known as the neural tube. During development progression, the top of the neural tube becomes the brain, and the rest of the tube turns into the spinal cord. These congenital (present at birth) defects occur when the neural tube does not close properly somewhere along its length.
Types of Neural Tube Defects
Doctors have divided these defects into several types. For example:
- Spina bifida
- Anencephaly
- Encephalocele
- Iniencephaly
Spina Bifida
This is one of the most common types of neural tube defects, and it occurs when the neural tube does not close properly. Moreover, this condition is also divided into different types. For example:
- Myelomeningocele (open spina bifida) – This form of NTD causes a fluid-filled sac that often protrudes from the baby’s back. It contains a part of the spinal cord, meninges, nerves, and cerebrospinal fluid (CSF). Furthermore, this type of disease is the most severe form.
- Meningocele – In such cases, a sac of fluid protrudes through an opening in the baby’s back. However, the spinal cord is not involved or damaged.
- Spinal bifida occulta – This form of NTD is characterized by a small gap in the baby’s spine. Moreover, there is no opening or sac in their back, and nerves and spinal cord are not damaged. In most cases, this type of NTD does not cause disability, and it is the mildest form of spinal bifida.
Anencephaly
This type of condition occurs when the baby’s neural tube does not close at the top during pregnancy. It usually causes an underdeveloped skull, scalp, and brain. Sometimes, parts of the brain or skull are missing. Unfortunately, most babies with anencephaly are stillborn or die shortly after birth.
Encephalocele
In babies with encephalocele, the neural tube does not close near the brain and may cause an opening in the skull. Furthermore, the brain and its membranes may protrude through the skull and form a sac-like bulge. In rare cases, babies with encephalocele may develop only a small opening in the nasal cavity or forehead area that is not noticeable.
Iniencephaly
This type of disease causes a severe malformation of the spine (misshapen) and usually a lack of neck. Less commonly, but babies with iniencephaly may also have their head bent backward. Other characteristics of iniencephaly include the connection of the skin from the face to the chest and scalp, which may be connected to the back. Most of the time, babies with this type of NTD are stillborn.
How Common are Neural Tube Defects?
These defects affect about 3,000 pregnancies each year in the U.S. For instance, there were about 3.6 million births in the United States in 2020. Moreover, the 2 most common types of NTDs are spina bifida and anencephaly, and they affect about 1,000 to 1,500 babies per year in the U.S. The other types of NTDs (including encephalocele and iniencephaly) occur quite rarely.
Symptoms
Usually, babies have different symptoms because they depend on the type and severity of the condition, the overall health of the mother before and during pregnancy, and other factors. For instance, some babies are born without symptoms, but others may have congenital disabilities. Moreover, babies with anencephaly and encephalocele are often stillborn or die soon after birth due to life-threatening complications. Check some general symptoms of NTDs below:
- Blindness (vision loss)
- Intellectual disability
- Lack of consciousness (sometimes death)
- Physical problems, including paralysis, urinary and bowel control problems, and others
When doctors suspect the fetus has a neural tube defect, they may refer him/her to other healthcare specialists. These birth defects affect babies differently.
Neural Tube Defect Signs
In most cases, if a fetus has a neural tube defect, you would not experience symptoms directly related to it. However, doctors may notice some abnormal changes during a fetal ultrasound. Sometimes, NTDs can be diagnosed before birth with this imaging test.
Causes
These congenital defects are often associated with reduced levels of folic acid in the woman’s body before and during early pregnancy. This substance is essential for the development of the brain and spinal cord in the baby. However, experts do not fully understand what exactly causes NTDs, but they think it is a combination of genetic, nutritional, and environmental factors.
Risk Factors
While it is not possible to determine the exact cause of NTDs, doctors have identified some factors that may increase the risk of your baby developing them. Check some examples below:
- Folate (folic acid) deficiency – This is the natural form of vitamin B9 that is essential for healthy fetal development. Your baby’s risk of developing NTDs increases when the mother does not have enough levels of folic acid before and during pregnancy. That’s why it is recommended to perform tests to make sure you have enough vitamin B9 before pregnancy, as well as other nutrients that support a healthy pregnancy.
- A family history of NTDs – If you have a baby with an NTD, the risk of the second baby having these defects increases.
- Antiseizure medicines – There are some types of this group of medicines that may increase the risk of your baby having NTDs, especially if they are taken during pregnancy.
- Diabetes and obesity – Both disorders significantly increase the risk of developing NTDs.
- Hyperthermia in early pregnancy – Pregnant women who have high body temperature in the early pregnancy may increase the risk of their baby developing NTDs. It may occur due to fever, a sauna or hot tub, or other causes.
- Opioid medicines – If you administer these medications during pregnancy, it also elevates the risk of your baby having NTDs. These are strong medicines used to relieve severe pain. Never take opioids during pregnancy without a doctor’s approval.
Diagnosis
In most cases, NTDs are diagnosed before birth. Check below some tests and procedures that help doctors diagnose these defects before birth:
- Blood tests – These tests are done to check for the amount of alpha-fetoprotein (AFP) in the blood during the 16th to 18th week of pregnancy. Increased levels of AFP may indicate NTDs, but more tests are required to confirm the condition.
- Fetal (prenatal) ultrasound – This is an imaging test that uses sound waves to produce images of the developing fetus during pregnancy. It helps diagnose several NTDs. Doctors often perform this test during the first and second trimesters of pregnancy.
- Amniocentesis – During this test, doctors will use a needle to get a sample of the amniotic fluid for testing. It is usually performed between 15 and 20 weeks of pregnancy because it carries some risks.
When it is not clear, doctors may perform additional imaging tests after birth to confirm the condition. For example, an MRI (magnetic resonance imaging) scan or a CT (computed tomography) scan.
Treatment
In general, there are some options to treat spina bifida and encephalocele, but they depend on the severity of the condition. Unfortunately, babies with anencephaly or encephalocele cannot be treated. Check below some options often recommended for babies with spina bifida and encephalocele:
Surgery
This is the primary treatment for babies with these types of NTD. They help place the protruding part of the baby’s brain and its membranes back to their proper position in the skull. Therefore, surgeons will close the opening. In babies with myelomeningocele, surgery is used to repair the opening in the baby’s spine. In most cases, babies with spina bifida require multiple surgeries to treat the symptoms and complications (such as hydrocephalus).
Sometimes, they may also recommend some procedures to improve the symptoms and prevent life-threatening complications.
Frequently Asked Questions
Can a baby live with a neural tube defect?
Yes, but it depends on which type of NTD your baby develops. For instance, babies with spina bifida and encephalocele may get treatment that fixes abnormalities caused by these disorders. However, those who develop anencephaly or encephalocele are often stillborn or die soon after birth.
When should I see my healthcare provider about neural tube defects?
If your child was born with an NTD, you should see a doctor regularly throughout his/her life. In addition, you should consult with your doctor before taking opioids or antiseizure medicines during pregnancy. Otherwise, it significantly increases the risk for your baby to develop an NTD.
What is the most common cause of neural tube defects?
Experts do not fully understand what exactly causes these congenital birth defects. However, they think there is a combination of genetics, nutrition, and environmental factors. Ask your healthcare provider if you have additional questions.
