Neural tube defects

The neural tube is the part of the embryo that becomes the brain and spinal cord, in other words, the central nervous system. It closes during the first weeks of pregnancy. Incomplete closure of the neural tube causes malformations of the spine, spinal cord, brain, and skull, collectively known as neural tube defects.

Several factors may be responsible for this type of birth defect, but the specific cause remains unknown. Certain conditions in the mother, however, may increase the risk of neural tube defects. They include:

• Vitamin B deficiency
• Use of certain antiepileptic drugs
• Diabetes
• Obesity

For couples who have had a baby with a neural tube defect, the risk of having another baby with a neural tube defect is increased.

Types of neural tube defects

There are several types of neural tube defects, such as:

Anencephaly (absence of the brain): Occurs when the head end of the neural tube fails to close properly. Affected fetuses are not usually carried to term or die at birth.

Spina bifida: The defect involves the incomplete closure of the spine. Related problems are determined by the size and exact location of the defect.

Screening

Screening tests only help determine a child's risk of being born with neural tube defects. Tests include an ultrasound and blood tests generally during the 2nd trimester.

Complications

Complications associated with neural tube defects are many and varied, but can also be nonexistent. Here are a few examples of some of the potential complications:

• Hydrocephalus (fluid build-up in the brain)
• Scoliosis (spinal deformity)
• Partial or complete paralysis of the lower limbs (legs)
• Fecal or urinary incontinence
• Convulsions and epilepsy
• Deafness and blindness
• Intellectual disability and developmental delay

Prevention

Folic acid, a B vitamin, plays a crucial role in the development of the central nervous system, particularly during the first month of pregnancy. A diet rich in folic acid, along with a daily multivitamin supplement containing at least 0.4 mg of folic acid and vitamin B12 can reduce the risk of birth defects.

Given that these abnormalities form very early in pregnancy, often before women realize they're pregnant, and knowing that many pregnancies are unplanned, it is recommended that women likely to become pregnant take a multivitamin supplement containing folic acid and vitamin B12. Furthermore, it is advisable to start this supplementation at least 2 to 3 months before conception or as soon as pregnancy is confirmed, and to continue throughout pregnancy.

Women who have an increased risk of giving birth to children with birth defects should consult their health care professional to determine the amount of folic acid that is right for them.

Treatment

There is no cure for neural tube defects consequences. However, various surgical procedures can reduce the severity of certain complications.

If you have any questions, do not hesitate to speak to your health care professional.