Topic of the Month May: Prenatal Medicine

The Agony of Choice: Prenatal Screening

Children with Down's syndrome are
considered to be intellectually disabled,
but they can develop very well;
© panthermedia.net/Gregory Dean

Trisomy 21 (Down's syndrome) is the most commonly diagnosed chromosome mutation that is detected prenatally. Yet even before a diagnosis is available, an expectant mother should be aware of what consequences this diagnostic finding will have. ”For some women it’s perfectly clear that this diagnosis does not change anything for them,” says Professor Klaus Vetter, Chief of Staff Department of Obstetrics at the Vivantes Klinikum Berlin-Neukölln (Vivantes Hospital). ”Others on the other hand know that they will not carry a child to term in case of such a diagnosis. They terminate the pregnancy.“

However, the finding does not automatically mean that the child will be born seriously ill. Only a fraction of children born with Down’s syndrome has serious organic diseases, such as heart defects for example. People with Down’s syndrome generally are only considered to be intellectually disabled, but their opportunities for development are much better, the more they are supported and emotionally accepted.

In the best interest of the child and its mother

In light of this, it may call into question what the Lifecodexx Company of Constance, Germany is planning: expected in 2013, it wants to launch a controversial blood test. The test is meant to reliably and without risk determine whether a child will be born with Down’s syndrome. To do this, the mother provides ten millimeters of blood, which also contains fragments of the fetal genome.

Previous tests to detect Trisomy 21 are either very inaccurate, like the so-called triple screen, or they involve an increased risk of miscarriage like in the case of chorionic villus biopsy.

The new blood test is controversial. German disabled rights organisations put the reproach of selection into play; © panthermedia.net/Astroid

”Looking for genetic material of the child in the mother’s blood usually has a low error rate that is slightly higher than that with an amniocentesis. Essentially, we have the same failure rate as chorionic villus biopsy. The risk of miscarriage due to invasive procedures such as amniocentesis or chorionic villus sampling is between 0.5 and 1.0 percent, depending on the study,” knows Vetter.

The gynecologist reports that this test is currently only used as a so-called second blind test in the U.S. for women at high-risk for having problems during pregnancy, this being women under 18 or over 35 years of age for example. If Trisomy 21 is prenatally detected in Germany, it has been estimated that around 90 percent of fetuses are being aborted.

Protection or selection?

Despite all that, providers and proponents of the new blood test have to put up with a lot of criticism. The fiercest criticism comes from German associations for the disabled. They allege that in the long run, this test makes complete selection and extermination of potentially disabled children possible. If worse comes to worst, Down’s syndrome will be eradicated that way.

There is no routine treatment - so
competent advice is in demand;
© panthermedia.net/
Monkeybusiness Images

Professor Vetter acknowledges that it is always correct and important to question the risks new procedures entail, however: ”Those who want to know whether Trisomy 21 is possibly at hand, will also be able to get this information elsewhere if necessary – with a different test“, says Vetter. The attempt to oppose the criticism of selection by limiting access to this test is therefore not effective.

Based on this controversy, Vetter therefore considers it his duty to educate expectant mothers well and clarify all pros and cons as well as consequences:”However, you should not over-simplify the counseling session. You need a lot of tact and sensitivity for this“, the gynecologist emphasizes. ”That is why I show all possibilities to these women. This way they are able to form their own opinion and reach a decision based on it. After all, we live in a free society.”

Nadine Lormis (Translated by Elena O'Meara)
MEDICA.de