Let's say that these tests, which we have heard under different names lately, are actually the same research.
There are free DNA particles belonging to both the fetus and the mother in her blood. These parts originate from cells that have reached the end of their normal lifespan (this is called apoptosis). While maternal ones originate from the bone marrow, fetal ones belong to the syncytiotrophoblasts of the placenta. Maternal DNA fragments differ from fetal DNA fragments in that they are larger and only 10% of all free DNA belongs to the fetus. Here, the free DNA fragments of the fetus are multiplied thousands of times and a chromosomal anomaly is sought. Although free DNA fragments may be found in the maternal blood even in the 5th week of pregnancy, it should generally be preferred after the 9th week. The half-life of free fetal DNA in maternal blood is expressed in minutes. Therefore, it cannot be detected in the mother's blood within 2 hours following birth.
Although this test can be performed from the 8th week onwards, it is more appropriate to perform it between the 10th and 13th weeks. Additionally, it can diagnose Tr.18 and Tr.13 as well as Monosomy.
In some special cases where a technical answer cannot be given, repeat blood collection may be required. Especially in cases of severe maternal obesity, the rate of failure to obtain results may increase due to the relative decrease in the amount of fetal DNA in the mother's blood. Pregnancies that start as multiple pregnancies and one fetus is lost in the early period may cause false positive results because fetal DNA is still present. Recently, a relationship has been found between malignancy detected in the mother and false positivity.
NIPT does not provide information about other rare chromosomal anomalies. If significant physical defects such as increased nuchal translucency, heart anomalies and brain anomalies are detected in ultrasound scans, the fetus may be at risk for some rare chromosome defects and all chromosomes should be analyzed.
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