Overview

Did you know that neural tube defects (NTDs) rank as the second most common congenital malformations in humans, impacting the development of the central nervous system?

Studies show that open neural tube defects, such as spina bifida and anencephaly, affect approximately 1 in every 3000 pregnancies.

Neural tube defects are often seen in babies when there's a problem with how the brain and spinal cord develop early on. They're a major reason for miscarriages and birth defects in newborns, making them a big concern for public health. 

Neural tube defects (NTD) can occur during the first month of pregnancy, sometimes before a woman is aware she's pregnant.  The cause for this can either be that the neural tube formation failed, or the nerve tissue evolved differently.¹ These issues further lead to abnormal development of the brain and spinal cord.

To be sure you are well-informed about open neural tube defects and their impact on newborns and later in life, continue reading. We’ll discuss all the aspects of NTDs in the guide, and some health tips for how to prevent these. 

Types of open neural tube defects

Spina bifida is the most common type of open neural tube defects (ONTDs).²

 Types of open neural tube defects include:

• Spina bifida: This occurs when the spine doesn't form properly over the spinal cord. Babies with spina bifida may face short-term or long-lasting physical problems such as paralysis, lack of bladder control, club feet, hydrocephalus (fluid buildup in the head), and intellectual disability. Many children require one or more surgeries after birth
• Anencephaly: In this defect, part of the brain and skull fail to develop. It happens when the neural tube doesn't close at the base of the skull. Babies with anencephaly often pass away in the uterus after 20 weeks of pregnancy or live for a very short time after birth
• Encephalocele: This is a rare condition where the brain or its coverings protrude through the skull. It can occur anywhere from the forehead to the lower back of the skull, or even near the nose and sinuses. Most children with encephalocele require multiple surgeries after birth
• Iniencephaly: This is a very uncommon and serious type of neural tube defect (NTD) where the head is severely bent backwards. The spine is also extremely twisted. Usually, the baby doesn't have a neck, so the skin of the face connects to the chest, and the scalp connects to the back. There may be other abnormalities too, like a split in the lip and roof of the mouth, heart problems, anencephaly (underdeveloped brain), and abnormal intestines. Babies born with this condition typically live only a few hours

Open vs closed neural tube defects

Neural tube defects (NTDs) are split into two main types³

• Open
• Closed

Open NTDs happen when the primary formation of the neural tube is disturbed, leading to conditions like anencephaly, myelomeningocele (which is an open form of spina bifida), and craniorachischisis. These defects cause a loss of nerve function below the affected area. 

Whereas, closed NTDs typically occur due to issues with the secondary formation of the neural tube. These defects are covered by skin, leading to conditions ranging from hidden spina bifida to severe spinal cord tethering. Closed NTDs often don't show symptoms and are usually found by chance.

Causes and risk factors

Genetic and environmental factors are key in causing neural tube defects. Besides these, other factors such as:

• Obesity
• Diabetes
• Immune system issues
• Folic acid deficiency
• Certain medications

And social and economic factors also have a significant impact.⁴

Diagnosis

Healthcare professionals have different tests to help find out if a baby has a neural tube defect (NTD) before it's born:

• Blood test: This test checks for a substance called alpha-fetoprotein (AFP) in the mother's blood between the 16th and 18th week of pregnancy. High levels of AFP can indicate an NTD in about 75% to 80% of cases. If AFP levels are high, more tests like ultrasound are done to get a clearer picture of the baby's health
• Ultrasound: This test uses sound waves to create images of the baby inside the womb. It's the most accurate way to diagnose many NTDs. Ultrasounds are usually done in the first and second trimesters of pregnancy
• Amniocentesis: This test involves taking a sample of the fluid from around the baby in the womb using a needle. It's done between 15 and 20 weeks of pregnancy to check for NTDs and other birth defects. However, amniocentesis has risks, so it's important to discuss them with your doctor

After birth, healthcare providers may use imaging tests like MRI or CT scans to diagnose some NTDs.⁵

Treatment

If your child has spina bifida or encephalocele, they may require surgery to:

• Close the defect and fix it
• Address hydrocephalus (fluid buildup in the brain)
• Treat bone problems or orthopaedic issues
• Address bowel and bladder problems

In addition to surgery, a baby may need:

• Rehabilitation
• Positioning aids to help them sit, lie down, or stand
• Braces and splints for support or to prevent deformities
• Medications

Discuss with your child’s healthcare providers about the risks, benefits, and potential side effects of these treatments.

Unfortunately, there is no cure or standard treatment for anencephaly. Treatment focuses on providing comfort to the baby. Anencephaly often results in death within days or weeks. Grief counselling services are available to support parents through this difficult time.⁶

Parental care and counselling

If your baby is born with an Open NTD, there are steps you can take to care for yourself and your baby:

• Attend all appointments with your baby’s healthcare provider
• Discuss with your baby’s healthcare provider about other specialists who will be involved in your child’s care, like counsellors, genetic counsellors, therapists, etc
• Contact your baby’s healthcare provider if you notice any concerning symptoms
• Consider genetic testing and counselling to understand your family's risk
• Share information about your baby’s condition with others and work with the healthcare provider to create a treatment plan
• Seek support from local community services and organisations specialising in birth defects

Tips to prevent open neural tube defects

The neural tube typically closes around 28 to 32 days after a baby is conceived, often before a woman knows she's pregnant. During this crucial time, normal brain and spinal cord development can be affected by various factors:

• Inadequate intake of vitamins like folic acid and other nutrients
• Infections
• Use of prescription medications or alcohol
• Exposure to harmful chemicals and substances
• Genetic issues

Folic acid, found in prenatal vitamins and certain foods like leafy greens, nuts, and citrus fruits, plays a crucial role in preventing Open NTDs.⁶ Taking a daily multivitamin with 400 to 800 micrograms of folic acid is recommended for all women of childbearing age. If you've had a child with an ONTD, your healthcare provider may suggest taking a higher dose before your next pregnancy, starting 1 to 2 months before conception and continuing through the first trimester.

Genetic counselling may also be advised to discuss the risk of future ONTDs and the option of a folic acid prescription to reduce that risk.⁷

FAQs

What are open neural tube defects (ONTDs)?

ONTDs are congenital anomalies affecting the development of the brain and spinal cord. These defects occur when the neural tube, which forms the baby's brain, spinal cord, and related tissues, fails to close properly during early pregnancy.

What are the implications of ONTDs in newborns?

ONTDs can lead to serious health issues in newborns, including paralysis, lack of bowel and bladder control, hydrocephalus (fluid buildup in the brain), intellectual disability, and even stillbirth or death shortly after birth.

Can ONTDs be diagnosed before birth?

Yes, ONTDs can often be detected during routine prenatal screenings, such as blood tests measuring alpha-fetoprotein levels and foetal ultrasound examinations.

What are the treatment options for newborns with ONTDs?

Treatment for ONTDs may involve surgical repair of the defect, management of associated complications like hydrocephalus and orthopaedic issues, and supportive care to improve the baby's quality of life.

What can parents do to support a newborn with ONTDs?

Parents can work closely with healthcare providers to develop a comprehensive care plan for their baby, which may include regular medical evaluations, rehabilitation therapy, assistive devices, and access to support services for families affected by birth defects.

How can I reduce the risk of ONTDs in my baby?

Taking prenatal vitamins containing folic acid before and during pregnancy, avoiding harmful substances, maintaining a healthy lifestyle, and seeking early prenatal care are important steps to help reduce the risk of ONTDs in newborns.

Summary

Open neural tube defects (ONTDs) are serious problems that happen when a baby's brain and spinal cord don't form correctly during early pregnancy. These defects can cause various health issues like paralysis, bladder problems, and intellectual disability. Doctors can often find ONTDs before birth with tests like blood tests and ultrasounds. Treatment may involve surgery and other care to help the baby live as well as possible. Parents can support their baby with ONTDs by working closely with doctors and getting the right care.