A person's DNA is usually distributed among 44 gender-independent and two gender-defining chromosomes (X and / or Y). When the egg fuses with a sperm cell, deviations from this distribution can occur, which will have more or less severe repercussions on the unborn child (fetus). A trisomy of chromosomes 21, 18 and 13 occurs in one of 1'000, 2'500, or 10'000 pregnancies, respectively. The likelihood of occurrence increases with the expecting mother's age. Further chromosomal maldistributions may occur in the sex chromosomes (X and Y), for example in the case of the Turner (X0) Syndrome.
v-natal® is based on the fact that, during pregnancy, DNA from the fetus enters the pregnant woman's bloodstream via the placenta, where it can be examined.
Why is it sensible to perform a v-natal® test?
v-natal® permits the detection of the most common chromosomal defects (trisomy 21, 18, 13 as well as maldistributions of the sex chromosomes, X and Y) in the unborn child.
Following blood sampling from the pregnant mother, a DNA analysis is performed by means of ‘next generation sequencing’. This method measures the amount of fetal DNA from the relevant chromosomes, which is present in the mother's blood. This allows to draw conclusions about any maldistribution.
v-natal® is available to mothers expecting one child or twins from the eleventh week of pregnancy onwards (following a first trimester ultrasound examination without any abnormal findings). A first trimester test (a combination of biochemical parameters, an ultrasound examination and a risk-calculation based on the expecting mother's age) is usually performed beforehand.
If this shows a trisomy risk of more than 1:1'000, v-natal® is recommended. In cases in which the first trimester test indicates a severely elevated risk of chromosomal maldistribution (more than 1:50), an amniocentesis may be preferable in some situations.
What will the expecting mother learn?
v-natal®, as NIPT, currently represents the most sensitive method for detecting trisomies without the need for an invasive examination of the amniotic fluid or the placenta. More than 98 out of 100 cases of trisomy are correctly detected and trisomy does, in fact, occur in more than 99 out of 100 cases in which the test results are positive.
Due to the high reliability of this test, chromosomal defects can be excluded with a very high degree of confidence if the test result is negative. By contrast, a maldistribution of chromosomes 21, 18, 13 or X and Y is highly likely in the event of a positive test result. We would, however, recommend to confirm the diagnosis by means of an amniocentesis or a similar procedure in this case.
What are the limitations of this test?
v-natal® examines the most common trisomies (21, 18, 13) and maldistributions of the X and Y chromosomes only. Other chromosomal disorders are not detectable by means of this test. All further common preventive check-ups during pregnancy (e.g. exclusion of deformities by means of ultrasound) must, of course, continue to be performed regardless of the test results.
On rare occasions, test results may be unobtainable or inconclusive in spite of careful blood withdrawal and analysis in the laboratory. In such cases, it may be necessary to repeat the analysis and request a new blood sample, if required. It is important to bear in mind that no conclusions about the health of the child can be drawn from this information.
Do statutory health and long-term care insurance providers reimburse the costs of v-natal®?
The costs of v-natal® will be reimbursed by statutory health and long-term care insurance providers as long as the risk resulting from the first trimester test is 1:1'000 or higher. This regulation has been in place since 15.07.2015.
In the event of lower risks resulting from the first trimester test, or if other indications exist, the costs of v-natal® may be borne by a supplementary insurance scheme.