ABOUT BIRTH DEFECTS
> What
are neural tube birth defects?
> How does
folic acid prevent birth defects?
What are neural
tube birth defects (NTDs)?
NTDs are a group of serious birth defects that occur very
early in pregnancy, before most women are even aware that
they are pregnant. The neural tube is the early structure
that grows into the brain and spine. It starts out as a
tiny pancake of tissue and normally folds inward. Next,
it fastens or zippers up to form a tube. (This happens around
the 28th day after conception when the embryo is no bigger
than a small grain of rice or the numbers on a penny.) When
the folding and zipping process does not happen correctly,
a small hole is left on the neural tube. As the fetus develops,
this hole will not close. Many NTD-affected pregnancies
result in miscarriage and some in stillbirth. Children born
with NTDs usually need life-long medical treatment.
The most common NTDs are spina bifida and anencephaly. Spina
bifida may cause leg paralysis, bladder and bowel problems
and/or other serious health complications. The severity
of disability depends on the size and location of the opening
on the spine. Usually, the larger defects and those higher
on the spine cause more disability. Children born with this
condition usually need surgery in the first few days of
life. Most people with spina bifida need to use a wheelchair
or leg braces throughout their life. Anencephaly is always
fatal. The baby is born with a severely underdeveloped brain
and skull.
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How
does folic acid prevent birth defects?
We don't completely understand how folic acid prevents birth
defects. Some studies suggest that taking folic acid makes
up for a diet poor in folates. Others studies suggest that
it counteracts a problem with the body's ability to use
and process folic acid (i.e., folate metabolism). Even though
we don't know how it works, there is plenty of strong scientific
evidence that folic acid prevents birth defects. This evidence
includes observational studies, non-randomized controlled
trials and randomized controlled trials.
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