IRENE ORFANOUDAKI MD, PhD 
Obstetrician & Gynecologist Surgeon

Detection of chromosomal abnormalities, such as Down syndrome, is one of the main goals of antenatal care and is one of the areas of Obstetrics where rapid progress has been made in recent years.

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Non-Invasive Prenatal Testing involves taking a small amount of blood from a pregnant woman very early in pregnancy, and isolating sections of fetal DNA, that is, genetic material of the fetus, that circulates freely outside the cells in the mother's blood.

Free fetal DNA is detected in the maternal circulation very early in pregnancy.

It consists mainly of small DNA fragments, 80% of which are large

<200bp and represents an average of 3% to 6% of the total free DNA in the plasma of the pregnant woman.

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Fetal DNA is then analyzed to detect known chromosomal abnormalities.

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Non-Invasive Prenatal Testing is a test that offers expectant parents the ability to detect major chromosomal abnormalities in the fetus and can be done from the 10th  week of pregnancy and determines the risk of having a fetus with trisomy 21, 18 or 13 in a single and twin pregnancy (reliability for a single pregnancy 99.12%).

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Specifically detected:

• Down Syndrome (Trisomy 21)

• Edwards syndrome (Trisomy 18)

• Patau Syndrome (Trisomy 13)

• Turner Syndrome (44 XO)

• Klinefelter Syndrome (44 XXX)

• Jacobs Syndrome (44 XYY)

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Today Non-Invasive Prenatal Testing is provided as a clinical service in most European countries, with obvious benefits.

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Indications:

• High risk pregnancy due to the age of the mother.

• Pregnancy where invasive prenatal testing is contraindicated

• Pregnancy with risk of miscarriage or family history of aneuploidy

• Pregnancy after assisted reproduction IVF (homologous or heterologous)

• Pregnancy at increased risk after screening and prenatal testing based on statistics (ultrasound or biochemical testing)

• Due to personal awareness.

If the Non-Invasive Prenatal Test shows that an abnormality is present, which indicates Down syndrome or some other syndrome, further testing will be needed to confirm the result.

The next step is probably getting a CVS or amniocentesis.

But if the result is negative, ie it is a normal result, then the gain is great, since in this way, and in the absence of other indications, the pregnant woman can avoid an amniocentesis that always carries the risk of miscarriage, even if it is small.