bifida is a debilitating disease. It is generally due to deficiency of folic
acid during pregnancy. Spina bifida is a neural tube defect wherein the brain,
spinal cord are not adequately developed. Prenatal testing for spina bifida
helps in detecting neural tube defects in the unborn baby. Read on to know how.
exact cause that leads to spina
bifida which is primarily a neural tube defect is not clearly known as yet.
The disease term actually means ‘cleft spine’ where the brain, spinal cord are
not adequately developed. Even the protective sheath called meninges, that
covers the brain and spinal cord is underdeveloped. Despite the years of
research it is still a mystery regarding the exact cause that leads to the
disruption or total closure of the neural tube. The condition eventually leads
to the development of malformation.
There are Four
Variants of Spina Bifida
- Closed neural tube
are three primary aspects that lead to spina bifida: genetic, nutritional and
environmental factors. This is why it is strongly advised that the woman
ensures a regular intake of folic
acid as the lack of it has been directly related to the disease in the
baby. The condition of the mother and the likelihood of the unborn child
developing the disease can be ascertained through prenatal testing.
How is the Prenatal Testing for Spina
prenatal testing for spina bifida happens in several stages during the pregnancy
term. During the second trimester, MSAFP and fetal ultrasound is suggested.
What is MSAFP - This is known
as maternal serum alpha fetoprotein screening. There is vital protein known as
AFP or alpha feto-protein which is produced in the placenta and the fetus
through a natural process. The screening basically measures the level of this
protein. When pregnancy occurs, it is natural that a certain amount of this
protein, which is very negligible, passes through the placenta and mixes with
the blood stream of the mother. During the MSAFP screening it is tested whether
the mother is having an abnormally high level of this protein in her blood
stream. If the levels are very high, it is an indication that the fetus is
having a neural tube defect.
- It is important to note here, that the only objective of the MSAFP screening
is not limited to test whether the baby is likely to suffer from spina bifida.
It has been found that the test cannot provide definite results on whether
there is indeed a serious problem with the fetus. If the screening reveals that
there is a very high level of AFP, the doctor immediately suggests some more
prenatal testing like an ultrasound or amniocentesis.
When is MSAFP
- MSAFP screening is also carried out in the second trimester of the pregnancy.
It can be a solo screening or in combination with other prenatal tests that is,
as a part of a multiple marker screen. This is considered to be a more
effective one as not only the neural tube defects are ascertained, but other
possible birth defects can also be successfully identified. These include
or down syndrome.
difference between these two prenatal testing through MSAFP lies in the fact
that, in the first trimester testing, the chromosomal abnormalities can be
identified. But the signs that directly define spina bifida are not really
evident. Whereas when the test is carried out in the second trimester, the
results are more definitive.
Spina bifida can be screened through this
prenatal test. Here a sample of fluid is drawn out from the amniotic sac that
envelopes the fetus. The fluid is then tested to find whether the baby is
likely to develop this disease. There is an important point to note here – the
amniocentesis test finds out the level of AFP and thereby conclude whether the
disorder is at all present or not. But the test does not indicate the degree or
severity of spina bifida.