Down Syndrome

Fact: Down Syndome is named after John Langdon Down, a british physician who first described the condition in 1887.

In the past only women over the age of 35 were automatically offered genetic counseling and diagnostic testing (amniocentesis or chorionic villi sampling) for Down Syndrome. According to a Practice Bulletin in the January issue of Obstetrics & Gynecology, all women regardless of age should be offered screening for Down Syndrome (Nursing for Women's Health, June/July 2007).
Things to Consider...
- Screening should be done before 20 weeks of pregnancy
- Nuchal Translucency (NT) and blood tests are less invasive screening methods
- Women considered to be at increased risk should be offered genetic counseling, amnio, or chorionic villi sampling (CVS)

What is Down Syndrome?
Down Syndrome (DS) or Trisomy 21 is a condition in which extra genetic material impairs physical,cognitive and behavioral development.

What Causes DS?

At the time of conception the baby inherits extra genetic information (an extra chromosome) from its parents, for a total of 47 chromosomes instead of 46.
It is unknown why this happens and therefore, there is no way to prevent it. However, research shows that woman above the age of 35 are at increased risk of having children with DS.

Screening/Diagnosis?


Screening tests estimate the risk that a fetus has DS and are generally noninvasive. However, screening tests do not offer definitive results.

Diagnostic tests are extremely accurate but are more invasive and have increased risk for complications. Diagnostic tests are usually only done following an abnormal screen in order to tell if the fetus actually has the condition.


Types of Screening Tests (during pregnancy):

-Nuchal translucency: Performed between 11-14 weeks of pregnancy. Using ultrasound, measurements are taken of the folds of tissue behind the developing fetus' neck. Fetus' with chromosomal abnormalities tend to accumulate fluid in that space. Increased measurement of the nuchal folds may indicate chromosomal abnormalities.

-The Triple Screen & and the alpha fetoprotein: Performed between 15-20 weeks of pregnancy. These tests measure the quantities of various substances within the mother's blood.

-Ultrasound: Often performed in conjunction with other screening methods. Some physical traits associated with Down Syndome can be seen.

Types of Diagnostic Tests:

-Amniocentesis: Performed between 16-20 weeks of pregnancy. This test involves the removal and analysis of a small amount of amniotic fluid.

-Chorionic villus sampling (CVS): Performed between 8-12 weeks of pregnancy. CVS involves taking a tiny sample of the placenta.

-Percutaneous umbilical blood sampling (PUBS): Performed after 20 weeks of pregnancy. A small amount of blood is sampled from the umbilical cord.


Medical Issues Associated with Down's

Two major problems affected approximately 1/2 of those diagnosed with Down's are congenital heart defects with increased risk of pulmonary hypertension and sensory deficits (hearing and vision). Other medical conditions include thyroid problems, intestinal abnormalities, seizure disorders, respiratory issues, obesity, an increased susceptibility to infection, and a higher risk of childhood leukemia.

Source .


For More Information National Association for Down Syndrome