During the first and second trimester of pregnancy, it is necessary for the pregnant woman to screen for trisomy 21 through an ultrasound or a blood test in order to assess the state of the health of the fetus. and determine the risk of Down syndrome.
This test can be performed in one of our best clinics in Istanbul Turkey.
Trisomy 21 Screening
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- For pregnant women whose screening in the first trimester revealed a high risk of Down syndrome 21.
- This test requires on average about two weeks to obtain the result.
- Anomaly detection rate greater than 99%.
Screening for Down syndrome in Turkey : Infos and Prices
Definition of a trisomy 21
Down syndrome is a chromosomal abnormality. People with Down syndrome have a supernumerary chromosome in chromosome pair 21. As a rule, a normal child is born with 46 chromosomes. Children with Down syndrome have an extra copy of one of these chromosomes, which is chromosome 21.
This extra chromosome affects how the baby develops his or her body and brain, which can lead to mental and physical problems. Although people with Down syndrome may look alike, they each have different abilities. People with Down syndrome have a cognitive development delay of genetic origin and most often an intellectual deficiency that can vary between slight and significant.
Causes of Down Syndrome 21
The most common cause of Down syndrome is an unexpected chromosomal abnormality of the 21st pair of chromosomes. The causes of this chromosomal accident are not yet clear, but the age of the mother is a risk factor. Older women are more likely to have children with Down syndrome. Moreover, all women can carry a fetus with trisomy 21, because this chromosomal abnormality is not usually hereditary.
If it is an oocyte or a sperm that has 24 chromosomes, instead of 23 participants in fertilization, the fetus will have trisomy because of this extra chromosome. Therefore, the father can also transmit this anomaly to his offspring.
This genetic abnormality can be detected before birth through an ultrasound or blood test carried out during the first two trimesters of pregnancy. The objective of screening for prenatal trisomy 21 is to estimate the risk to the fetus of being a carrier of Down syndrome.
Screening for Down syndrome 21 Turkey
In the first trimester of pregnancy, the risk assessment for trisomy 21 in one of the clinics in Istanbul Turkey is based on three elements: is based on three elements:
Mother’s age: The older the mother, the higher the risk of Down syndrome.
Nuchal Clarity Measurement: During a first-trimester ultrasound: the more the nape of the neck is sparse, the greater the risk of Down syndrome. This means the gap between her neck skin and her spine. If the distance is greater than usual, the probability of Down syndrome is higher. A blood test that can be performed in an accredited laboratory, on the first or second month, to measure serum markers.
These doses, combined with the age of the pregnant woman, can determine the risk of Down B syndrome. During the second trimester of pregnancy, if screening for trisomy 21 was not performed, amenorrhea can occur for up to 18 weeks.
The risk calculation is then based on:
- Maternal age
- The number of serum markers in the second trimester (blood test)
- Measurement of Nuchal Clarity
Non-invasive screening for trisomy 21 via fetal DNA analysis
With Turquie Santé, it is currently possible to determine if the fetus could carry trisomy 21 through blood tests of pregnant women in the best clinics in Istanbul Turkey, and with the most affordable prices. This test, which analyses fetal DNA in maternal blood, remains a screening, which means that any positive test must be followed by a sample (amniocentesis or trophoblast biopsy) to verify the result.
Conversely, the test can be erroneously reassuring in about 0.5% of trisomies 21. In about 1% to 5% of cases, test results cannot be returned for technical reasons.
According to our current knowledge, prenatal diagnostic professionals in Istanbul Turkey do not recommend this screening test as a substitute for the current measure of cervical clarity that combines maternal age, ultrasound, and maternal serum markers. When it is above 1/250, the risk is high, low risk of less than 1/250.
The results of the Down syndrome screening?
The results will be provided by the doctor who prescribed them. It is manifested in the risk that an unborn child becomes a carrier of Down syndrome. So it’s a probability rather than a certainty.
Finally, this screening test is not perfectly flawless: it is feared that 5% of pregnant women are considered to be at «high» risk, but the vast majority of them are pregnant with children with normal karyotype. On the contrary, in rare cases, the risk may be considered “low”, but the child is ultimately a carrier of Down syndrome.
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