Neural tube defect

November 12, 2012

Neural tube defect

Neural tube defect occur in around 1 in 1000 births in the US making the condition one of the most common birth defects. A neural tube defect occurs very early on in the baby’s development and is an opening that occurs either the brain or the spinal cord. The spinal cord is one of the first things a foetus will develop and starts off as a flat area. Within 28 days after conception it will have rolled itself into a tube. A neural tube defect occurs when the tube does not completely close, leaving a small opening.

There are two forms of neural tube defect, or NTD with the first and most common form being called an open NTD. If the skull or vertebrae have a defect of some sort that causes the brain or spinal cord to be exposed at the time of the birth, then they are known as open NTD’s. The second form, known as a closed NTD occurs when defect in the spine or brain is covered with skin. Examples of an open neural tube defect include:

  • Spina Bifida

  • Anencephaly

  • Encephalocele

Examples of the less common closed NTD’s include:

  • Lipomyelomeningocele

  • Lipomeningocele

  • Tethered cord

There is one more potential NTD that occurs more commonly than those mentioned previously, called Spina Bifida Occulta. In this condition the spinal cord or surrounding nerves are not affected but there is bony deformation on one or more vertebrae. The condition doesn’t typically produce symptoms and as the spinal cord is not affected it is hard to define the condition. More studies and research is required in this area in order to narrow down the similarities between the causes of this condition and other neural tube defect’s.

Prevention of neural tube defect

Extensive research and studies into neural tube defect has revealed that women who supplement their diet with folic acid can significantly reduce the chances of their baby developing the condition once they conceive. A diet high in folic acid or the consumption of a daily multi-vitamin is recommended for all women of childbearing age and particularly for those who are actively trying to get pregnant. Any woman who has previously experienced an NTD pregnancy should take even higher doses but speak to your doctor who can advice you and prescribe exact dosages.

Detection of neural tube defect

There are a number of prenatal tests that are able to detect an NTD during pregnancy. A maternal serum alpha-fetoprotein is a blood test that is performed between 16 and 18 weeks into the pregnancy. A high-resolution ultrasound will be able to detect an NTD 16 weeks into the pregnancy or earlier. Amniocentesis samples the amniotic fluid surrounding the baby and is performed after 25 weeks.


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