During pregnancy, application of screening tests known as 1st trimester screening test, double test, and triple test should be performed to monitor chromosomal diseases such as Down’s syndrome. And ultrasound follow-up is also important during pregnancy. Since these tests do not require surgical operations, application is not risky for mother and baby. On the other hand, amniocentesis and chorionic tissue sampling (CVS) require surgical operations and they are categorized as second group tests also known as invasive prenatal diagnosis tests.
Recently, new non-invasive DNA based tests are added to the previous two test groups. Non-invasive tests, it is to say, are more reliable as compared to former ones; however they have not yet reached the precision with 99,9% accuracy for diagnostic purposes with respect to amniocentesis and similar invasive tests. Therefore, it is recommended to use for screening.
With the help of these NIPT tests the risks of chromosomal diseases such as Down’s syndrome can be determined after 9th week of pregnancy. A small amount of blood sample carrying the fetal DNA taken from prospective mother is used to identify the risks of chromosomal diseases like trisomy 13 and trisomy 18 which are essentially important for survival. In addition to such trisomies, identification the risks of Down’s syndrome (trisomy 21) and sex chromosemes related diseases can definitely be fulfilled.