ABOUT FOLIC ACID

ABOUT BIRTH DEFECTS

FURTHER READING

Frequently Asked Questions

> What are neural tube defects (NTDs) and how are they caused?
> Who is at-risk for an NTD pregnancy?
> What is NC's NTD rate?
> What is the cost of NTDs?




What are neural tube defects and how are they caused?
A neural tube defect is a birth defect that occurs when the neural tube, the embryonic structure that grows into the brain and spine, fails to properly close around 28 days post-conception. At this stage the embryo is about 2 - 3 mm, about as big as the numbers on a penny. The neural tube starts out as a tiny pancake of tissue, consisting of the neural groove, neural fold and neural crest. First, this folds inward. Next the tube fastens or zippers up. When the zipper does not close completely, a small hole is left. As the fetus develops, this hole will not close. The exact place of the defect along the neural tube will determine the type of NTD that develops.

The most common NTDs are spina bifida and anencephaly. Spina bifida is a bony defect of the posterior vertebral arches with herniation of neural tissue and meninges that is either covered by skin (closed) or is not (open). There are several types of spina bifida. Generally, the higher the defect occurs on the spine and/or the larger the defect, the greater the disability. Anencephaly is the absence or almost complete absence of the brain and calvaria (skullcap). This condition is always fatal.


The March of Dimes has an extensive number of Fact Sheets on birth defects, which can provide a more extensive look at spina bifida, anencephaly and other NTDs than the scope of this site allows.

Around 95% of NTDs occur as an isolated defect of unknown etiology. How folic acid prevents NTDs is not well understood and is an area of active research. Most studies suggest that taking a supplement containing folic acid counteracts poor dietary intake. More recent studies are investigating if supplemental folic acid compensates for genetic variations in folate metabolism.

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Who is at risk for an NTD-affected pregnancy?

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What is NC's rate of NTD's?
North Carolina has one of the nation's highest rates of NTDs, Approximately 200 pregnancies are affected each year. Over half will not survive due to miscarriage, termination or fetal death. The southeastern states have higher NTD rates than other areas of the country. The exact reason for this disparity is not known. However, North Carolina has a high number of women with known NTD risk factors-- maternal diabetes and obesity, English/Irish ancestry, lower socioeconomic status, and Hispanic ancestry.



Source: North Carolina Birth Defect Monitoring Program

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What is the cost of NTDs?
In February 2000, an article in the journal Tetratology reported the lifetime cost of care of a child with spina bifida at around $250,000 - $300,000; however, this was based on data from 1992. Since that time, there have been significant advances in the treatment of children with spina bifida along with rising medical costs in general. This led many to believe that the current lifetime cost is significantly higher-- perhaps as much as three times higher-- although no one has published a study to support that belief.

Using the lowest, published cost figure, it is estimated that if NC women took a multivitamin with folic acid daily, NC would save $2 - $4 million annually in Medicaid costs.

The emotional and physical costs for families is very high. Half of NTD pregnancies do not survive. Children born with spina bifida can have many medical complications from mild to severe, including paralysis of the legs, loss of bladder and bowel control, and learning disabilites. Nonetheless, many children with spina bifida grow up to lead successful and productive lives. Those children who are lucky enough to have access to special care and services often lose them at age 21, so medical care can always be a concern.

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