Prenatal Test Accurately Detects Down's Syndrome

Armen Hareyan's picture
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New prenatal test is accurate and non-invasive in detecting if the fetus suffers Down's syndrome or any other chromosomal disorders. The test uses fetal DNA of mother's blood to identify fetus's health complications.

Down's syndrome is a type of chromosomal conditions, which occur because a child has three copies of chromosome 21 instead of two. The disease causes mental retardation later in life, and most of mothers decide to stop pregnancy when they find out their child has this disorder. Other diseases occurring because of chromosomal disorder are Edward syndrome (killing 50% of children during the first week of life) and Patau syndrome (killing 80% of infants).

Researchers have been long searching for a new non-invasive method to test an unborn baby for chromosomal disorders. This innovative prenatal test is developed by researchers from Stanford University in California and offers accurate testing using only a small sample of mother's blood.

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Researchers examined 18 pregnant women, and the new test accurately detected 9 fetuses with Down's syndrome and 3 fetuses with chromosomal disorders.

Currently available methods for identifying if a fetus suffers Down's syndrome are amniocentesis and chorionic villus sampling (CVS). The first one is being performed by inserting a needle into abdominal wall and then into the uterus of a woman to get amniotic fluid, which is then tested for chromosomal disorders. CVS test takes a uterus tissue through the cervical opening again to test it for possible conditions.

This new method has several advantages compared to invasive methods: amniocentesis and CVS can be performed only after the 15th week of pregnancy, while the new test can be performed at 5th week of pregnancy. Old methods are invasive and carry a 1% heath risk for fetuses. This is why the test was being performed in high risk women only - those who have family history or are older than 45, while the new test can be used as a routine screening for every single pregnant woman. Besides, old tests take from 2 to 3 weeks to give results, while the new test takes only a couple of days to be ready.

However, the new test is not perfect - it has one disadvantage compared to invasive methods - it does not diagnose any chromosomal disorders, but only identifies potential risk, and when the risk exists, amniocentesis or CVS should be done anyway.

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