Genetic testing is a highly advanced process whereby tiny samples of human blood and/or body tissue are examined by professionals.
This is often carried out to establish if the person being tested carries certain genes for specific inherited illnesses or disorders. In many cases, genetic testing is advanced and thorough enough to allow doctors to identify absent or flawed genes. Various body fluids are also used during different tests, depending on what the doctors are looking for.
Testing on unborn babies
Genetic testing can also be carried out on an unborn child. For this type of testing your doctor may suggest either an amniocentesis test or a chronionic villus sampling (CVS) test.
The amniocentesis test is usually only carried out between 16 and 18 weeks of pregnancy. Basically, the process involves drawing out a very small amount of amniotic fluid using a needle which is inserted through the mother’s tummy and into the womb from where the fluid is withdrawn.
There are two different types of tests which fall into this category. One is the rapid test and the other is the full karotype test.
The rapid test
The first of these two tests picks up faults in certain chromosomes which are the parts of the body’s cells that carry its genes. Various physical and mental irregularities can be highlighted via a rapid test. These are Down’s Syndrome, Edward’s Syndrome and Patau’s Syndrome. All of these are caused by an extra chromosome in different genes.
This amniotic fluid can be tested not only to establish if there are any genetic inconsistencies, but also if there are problems with the baby’s lung formation, as well as to determine the sex of the developing child.
The full karotype test
A full karotype test checks all of the body’s genes which each contain 23 pairs of chromosomes.
Despite huge leaps in medical technology, it’s always wise to discuss with your doctor the small risks of miscarrying that are possible with this procedure.
The CVS route
Another procedure your doctor may choose for you is the chronionic villus sampling (CVS). This test is administered usually only between 10 and 12 weeks of pregnancy. It is also to ascertain the possibility of any chromosome problems with your developing baby. It will also, however, indicate other inherited disorders and is often recommended if one or both parents have a family history that could be a risk factor to your baby’s health.
Paternity testing is also performed via this means as it provides access to DNA. An almost fool-proof method of paternity testing, CVS enables DNA to be collected from the unborn baby which can then be tested against the potential father’s DNA.
The test gets its name, chorionic villus sampling, because this is the name of the cells situated on the placenta where it attaches itself to the uterine wall.
How it’s done
The CVS is performed in one of two ways: either via a catheter guided by an ultrasound through the cervix to the placenta, or via an ultrasound guided needle through the tummy.
As with the amniocentesis test, CVS is an invasive procedure and therefore also carries a small risk of miscarriage; and so as with any decision regarding the pregnant body your obstetrician or health professional should be consulted first.