There are many trisomies, but thanks to a blood test, it is no longer necessary to make amniocentesis for a diagnosis. What trisomies are and everything about the blood test, you will find out here.
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- How does the blood test work?
- Blood test vs. Amniocentesis
- What do the individual trisomies mean?
- Which health insurances charge the costs of the blood test?
Since 2012 gives an alternative to the risky amniocentesis. A blood test can clarify trisomies without any risk. However, the test is no cash flow and with 200 to 300 euros also anything but cheap. But a decision of health insurance companies and doctors to take this test as a cash benefit in risk pregnancies, is foreseeable. Nevertheless, there are many critics, which is why there is still a debate going on.
How does the blood test work?
For the test, the expectant mother is taken blood. In addition to the genetic information of the mother are in her blood already DNA fragments of her unborn child. These pass from the placenta into the mother's bloodstream. These fragments are already enough to read chromosome anomalies and to be able to diagnose seven trisomies. Usually, trisomy 21, 18 and 13 are studied. According to the manufacturer, there is a 99.8 percent confidence in the test result.
Blood test vs. Amniocentesis
The blood test is a non-invasive test method, which means that the unborn child is not involved in the test. For the mother, the test is a regular blood sample. Therefore, the test has no risk of infection or miscarriage. The test is already possible from the ninth week of pregnancy.
In an amniotic fluid examination, the genetic material of the unborn child is removed from the amniotic sac by means of a hollow needle. The amniotic fluid contains childish cells that can be analyzed in the laboratory. In addition to the test for trisomies, the concentration of two proteins can also be measured. These give an indication of malformations of the spine and the abdominal wall. The test is possible from the 16th week of pregnancy and offers similar to the blood test a 99 percent certainty. Because it is an invasive test, this test is risky. Because while the hollow needle is inserted into the amniotic sac, it comes very close to the unborn child and there is a risk that the child will be injured. There is also a miscarriage risk of 0.1 to 0.5 percent. An amniotic fluid examination is taken over at risk pregnancies by the health insurance companies.
What do the individual trisomies mean?
Trisomies are changes in the genome, which are associated with various physical and mental impairments. The structure or the number of chromosomes is different. Normally, every chromosome is duplicated. If there is a trisomy, it exists in triplicate. In the known trisomy 21 or Down syndrome, the chromosome number 21 is affected. The additional genetic material leads to a variety of mental and physical impairments. Trisomies can affect any chromosome, with many malformations being so severe that miscarriage occurs early. However, there are three trisomies that are diagnosed by doctors during pregnancy.
Trisomy 21
There are four different forms of Down syndrome (= trisomy 21), which are summarized here. In Germany, about 1200 children with Down syndrome are born each year. The symptoms can be of varying degrees. In addition to external features such as dwarfism, a short thick neck, a small round head, which is flattened at the occiput, people with Down syndrome have a saddle nose, but also a four-finger furrow and other visual symptoms are possible. In addition, malformations of the internal organs or functional defects may be formed.
Tip: With different eyes: Fabian Sixtus Körner on trisomy 21 and traveling with a child
Trisomy 18
Edward syndrome (= trisomy 18) occurs in approximately one in 5, 000 live-born children. The type of malformations, as well as their characteristics are very versatile. In total there are about 150 different malformations associated with the syndrome. This includes possible malformations of the heart, head, brain, kidneys and extremities.
Children born with the Edward syndrome expect a very short life, averaging four days. 10 percent of boys and 55 percent of girls survive the first year of life. At the age of five, about 15 percent of girls still live. However, only 10 percent of affected fetuses are born alive.
Tip: Trisomy 18: What Edwards Syndrome means to a baby
Trisomy 13
Trisomy 13 is also referred to as Pätau syndrome, which is found in about 1 in 10, 000 live births. This syndrome is characterized by various malformations and behavioral problems. The different symptoms can occur individually and in many combinations. The malformations can affect, among other things, the head, eyes, extremities, but also the brain, heart, digestive system or genitourinary tract.
Only ten percent of affected fetuses are born alive. Of these, 60 percent die within their first year of life. Girls usually survive longer than boys, yet only 10 percent of affected children are older than five years.
Which health insurance companies will cover the costs of the blood test?
Although the decision of health insurance companies and physicians regarding the assumption of costs is foreseeable, but so far only a few health insurance companies bear the costs. But even if an agreement is reached, the costs are only borne by high-risk pregnancies. However, you can ask your health insurance company in advance which pregnancy examinations are paid. If your doctor recommends the blood test, you should apply for a reimbursement.
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