[1][2][3] This testing analyzes small DNA fragments that circulate in the blood of a pregnant woman.
Analysis of cffDNA from placenta provides the opportunity for early detection of certain chromosomal abnormalities without harming the fetus.
[5] Non-Invasive Prenatal Testing, or NIPT, is a simple blood draw that screens for chromosomal abnormalities of a fetus while still in utero.
When this screening was first performed it was used to determine the sex of a fetus, now it is also used to find aneuploidies in fetal DNA.
[13] cffDNA, RNA and intact fetal cells can all be used to assess the genetic status of the fetus non-invasively.
[18][19][20] These methods of cffDNA sequencing have sensitivity and specificity rates greater than 99% in identifying Trisomy 21.
The low false positive rate (1–3%) is one of the advantages of NIPT which allows pregnant women to avoid invasive procedures.
[31] When a woman is pregnant the placenta will release small DNA fragments into her bloodstream (cffDNA) which can be sampled without disturbing the fetus in utero with an invasive procedure.
[7] The NIPT testing uses chromosomal next generation sequencing to track the variation in fetal genes that could be signs of abnormalities.
[32] A blood sample is taken from the perspective mother and the cffDNA is analyzed for several aneuploidies and other genetic markers.