A noninvasive and safe blood test for pregnant women helps to discover the risk of Down syndrome in the fetus. Although until now ultrasound and amniocentesis were the main methods by which doctors detected the risk of this chromosomal malformation in the fetus, the specialists developed modern technologies for sequencing and reconstructing fetal DNA from the blood, to analyze with greater accuracy the risk of chromosomal malformations, including Down syndrome.
Currently, a pregnant woman goes through two standard screenings to detect the risk of Down syndrome in the fetus or other types of chromosomal abnormalities. The first is ultrasound, and the second, amniocentesis, the invasive and more dangerous method than the ultrasound test.
Both tests are performed in the first two trimesters of pregnancy and have an anomaly detection rate between 65 and 96%.
Blood test to detect Down syndrome in the fetus
The researchers developed a noninvasive method of detecting chromosomal abnormalities in the fetus through a modern blood test, DNA sequencing that the mother and fetus shared. The blood test involves collecting 10 ml of blood from the pregnant woman.
It can be done in the first 12 weeks of pregnancy. The DNA cells that the mother and baby share are analyzed in the laboratory, where the specialists isolate the fetal DNA, then count the chromosomes in it. Chromosome counting is relevant for the detection of Down syndrome, because children suffering from this abnormality have an extra chromosome than the others, which is why the condition is also called trisomy (in a normal organism, the chromosomes are 46 and come in pairs). , and the presence of an additional chromosome determines the trisomy).
In the analysis of blood for the detection of Down syndrome, the specialists track the presence of anomalies on chromosomes 13, 18 and 21, directly involved in the diagnosis of several syndromes: Down, Palau and Edwards.
This state-of-the-art DNA sequencing and reconstruction technology in fetuses for the purpose of chromosome analysis is a safe and simple alternative to existing methods - amniocentesis and sampling of chorionic villi. They are invasive and present an increased risk of complications (miscarriage or pregnancy loss).
Who is the blood test for chromosomal abnormalities?
Doctors who have developed this new method of diagnosis recommend the test especially to pregnant women who have become pregnant after 35 years, have had problems or complications in previous pregnancies or have a family history of chromosomal abnormalities.
The sequencing test is not recommended for pregnant women with minimal risk of Down syndrome or those with multiple pregnancy. The researchers claim that the method does not provide results relevant to multiple pregnancies, as it has not been sufficiently tested and evaluated on such pregnancies.
The procedure is scientifically proven and internationally validated and has a detection rate of Down syndrome in the fetus of almost 98%. The only disadvantage of this test is the high cost. But the specialists are confident that if the demand is very high, the price will fall and more and more pregnant women will be able to benefit from its benefits.
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