Prenatal Testing for Down Syndrome

Traditionally, tests for Down Syndrome were usually performed based on the age of the mother during the pregnancy. Now tests for Down Syndrome are recommended regardless of the age of the pregnant woman and there are various non-invasive tests available to assist in the diagnosis of Down Syndrome. Some of the tests that can be performed for the diagnosis of Down Syndrome include Amniocentesis, CVS, PUBS, genetic diagnosis, and some tests to analyze the DNA of the baby. Determining whether to receive these tests and which ones should be performed during pregnancy is up to the mother but reasons to choose these tests include the age of the pregnant mother and a family history of Down Syndrome.


The first type of test that you can perform for the Diagnosis Of Down Syndrome is known as Amniocentesis. This process allows the doctor to withdraw a small sample of the fluid that is surrounding the fetus. This amniotic fluid is withdrawn with the use of a needle that is inserted into the uterus of the pregnant woman and this fluid is then taken to and to for an analysis of the chromosomes. This test is usually down sometime after 15 weeks of pregnancy.


The next test, which can be used, is chorionic villus sampling in which cells are taken from the placenta and analyzed for the presence of Down Syndrome. This test can be performed earlier than Amniocentesis, at 9 to 14 weeks of pregnancy.


The third type of test to perform for the diagnosis of Down Syndrome is PUBS or percutaneous umbilical blood sampling. As its name suggests blood from the umbilical cord is taken in order to examine the cells for any chromosomal defects. This test can pose higher risks for miscarriage and so is only performed when other tests are inconclusive and after 18 weeks of pregnancy.

Genetic Diagnosis

Certain types of genetic diagnosis are being developed to provide testing that keeps up with current technology. Pre-implantation genetic diagnosis allows for those using in vitro fertilization to check the embryo before it is even implanted to see if there are any genetic abnormalities, including Down Syndrome.

Analysis of DNA

There are other testing methods, which are being developed in the hopes of determining chromosomal abnormalities even better than current methods available. One test that is available in certain areas include extracting fetal DNA found in the bloodstream of the mother and using that to determine any abnormalities present in the baby. If no tests are performed during pregnancy, there are tests, which can be performed after the baby is born including a chromosomal karyotype. This test will determine Down Syndrome by checking to see if an extra chromosome is present in any of the cells tested.

If you would like to know more about diagnosis of Down syndrome, contact Ariosa Diagnostics. They are available to answer your questions at 1-855-9-ARIOSA.

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