Genetic testing is important because it can identify changes in chromosome, genes etc. and can help you in identifying any underlying health problems that your child might have acquired due to genetic disorder. Till date more than 1000 genetic tests have been developed and many more are under research. Genetic testing can be done in various ways however following three are the most common
Biochemical Genetic Test
This test is performed to monitor the abnormality in protein levels and their activities because a change in any of these can result in a genetic disorder.
Molecule Genetic Test
This test is performed on single genes and helps in identifying variations in DNA that can lead to a genetic disorder.
Chromosomal genetic test
This test is a bigger version of the molecule genetic test and identifies variations in whole chromosomes or bigger amount of DNA and is used for identifying major genetic changes. An example of an major genetic change could be occurrence of extra number of chromosomes than required.
Getting a genetic test done is not compulsion but slowly since people have started realizing the importance of these tests millions of tests are being performed daily alone in USA. Statistics show that at least 3 to 5% of babies are born with birth defects related to genetic disorder. So if in case you or someone in your family has suffered with a genetic disorder in the past than going for a genetic test would be a good choice. As mentioned before that getting these test done is optional but it would be important to consult your doctor or midwife before going for these test. Genetic tests are both type some of them are very specific ones which are needed to be performed on only few cases but there are some common test as well which can be performed on all type of pregnancies.
Common genetic test for birth defects
Tests like down syndrome, trisomy 18, trisomy 13, open neutral tube defects, chromosome abnormalities etc. can be performed in every pregnancy. A baby might accidentally get an extra pair of chromosomes even though there is no existence of genetic disorder in the history of the family and hence these tests are useful in those cases. Defects like trisomy 18 and 13 result in mental retardation and are sometimes life-threatening as well.
The risk of these problems increase among mother who are conceiving at an older age.
Similarly neutral tube defect is also a random defect wherein the babies spinal cord gets interrupted and does not fully tighten into a tube. Spina bifida is one of the most common type of neutral tube defect and if someone in your family has suffered with this defect in the past than it is very important to get this test done as this defect can result in partial paralysis, mental retardation, gallbladder issues etc.
These tests do not have any kind of side effects but they actually do not identify the problem. These are just screening tests which provide information that whether a woman should continue with further diagnostic or not.
The most common type of screening tests are
This test is performed to identify risks such as down syndrome, trisomy 18 and open neutral tube defect and is performed in two stages. The first stage of test is performed in the first trimester after 10 weeks of pregnancy. The first stage involves both ultrasound and blood test and the results are delivered after approximate one week of testing. If in case your Doctor would identify something serious than he or she will immediately recommend you for further diagnostic testing otherwise you will need to undergo the second stage of blood screening test. The second stage of test is performed after 16th week of pregnancy.
Maternal serum quad screen
Commonly referred to as quad screen test is performed to identify abnormality in proteins level and activities. This test does not requires an ultrasound and is performed after 15 weeks of pregnancy. Again this is a screening test and based on these results the Dr. would recommend a diagnostic testing if required. One point to note here is that this test is generally only recommended to woman who have not undergone the sequential screen test previously.
20 week ultrasound
As the name suggests this test is performed during second trimester, generally after 18 weeks of pregnancy. Lot of people confuse this test with gender identification test, however this test is performed to identify the risk of any kind of birth defects or other abnormalities such as heart issues, kidney, limp and brain problems. This test is not very successful for identifying genetic disorder.
These tests are not a compulsion but are recommended to every woman during pregnancy and whether one should go for these tests or not depends upon individual preference. Only your genetic counselor would be able to properly guide you during this test as to whether you should undergo the next level of diagnostic test or not.