Prenatal diagnostics: is my child healthy?

It goes without saying that all expectant parents hope that their child is born healthy, so prenatal examinations are a standard part of every pregnancy. If the first detailed check-up - in Switzerland this is usually carried out in the second to third month - is inconspicuous, seven routine check-ups follow until delivery.

However, if a high-risk pregnancy is determined, for example due to the woman’s age or family history, prenatal diagnostics can provide more information on the embryo’s health. These tests can be used, for example, to estimate the risk of malformations and hereditary illnesses (e.g. trisomy 21).

Prenatal diagnostics also entail challenges and risks. On the one hand, there are no prenatal tests that provide 100% certainty without an examination risk. Invasive prenatal diagnostics can trigger a miscarriage. On the other hand, the results can, under certain circumstances, throw up difficult existential questions for the parents.

In most cases, the results don’t indicate how severe a possible impairment of the child could be. When is a life worth living? Before undergoing any prenatal examination, it is important to have a detailed and personal consultation with the doctor.

Prenatal diagnostics differentiates between invasive and non-invasive tests. The term “non-invasive” means that the tests don’t penetrate the uterus. It therefore poses no risk of miscarriage or of injury to the unborn child.

• Measuring nuchal translucency: The thickness of the liquid poster on the neck of the unborn child may be an indication of a chromosomal defect. In the 11th to 13th grade From the first week of pregnancy, ultrasound measurement is part of the standard examination. The interpretation of the ultrasound is dependent on the doctor’s experience.
• First-trimester test: If the result of the nuchal translucency measurement identifies abnormalities, a first-trimester test is usually carried out. In this case, the mother’s blood test results, her age and the foetus’ nuchal translucency are used to calculate a statistical risk factor for a chromosomal abnormality. The first trimester test provides only a statistical value calculated by a computer program; it is not a diagnosis. 
• Non-invasive prenatal testing (NIPT) If the first-trimester test shows a risk of 1:1000 or higher for trisomy 21, 18 or 13, the expectant parents can choose to have the child’s DNA tested in the mother’s blood. Such a blood analysis is possible from the 12th week of pregnancy. Possible from the first week of pregnancy. NIPT can detect a genetic abnormality such as trisomy 21, 18 or 13 with a high degree of accuracy. But it is not 100% reliable. Like the first trimester test, the NIPT is not a diagnosis, but a statistical value. Therefore, in the event of a positive or unclear result, many doctors recommend an invasive test for clarification.
• Fine ultrasound: Between the 19th and 22nd week of pregnancy. From the second week, it is possible to examine the organs of the fetus with a fine ultrasound, also known as organ screening. If parents know before the birth that their child requires special treatment, they can consult specialists early on.

With invasive tests, the specialist takes a sample of the amniotic fluid, blood from the umbilical cord or tissue from the placenta to examine cells of the foetus directly. Invasive tests deliver relatively precise results, but they are associated with specific risks.

• Chorionic villus sampling (CVS): A fine needle is used to remove a sample of chorionic villi from the placenta through the abdominal wall for testing in the laboratory. The results are available in a few days. The invasive test is usually performed between the 10th and 14th week of pregnancy. week after a positive or unclear NIPT. The risk of a miscarriage is 0.5 to 1.5%. If the result of the CVS is inconclusive, there is the option of amniocentesis.  
• Placental biopsy: From the 19th week. After the first week of pregnancy, this is no longer referred to as a chorionic villus sampling, but as a placental biopsy. 
• Amniocentesis: During amniocentesis, fluid is taken from the amniotic sac with a thin needle. It takes two to three weeks to analyse the amniotic fluid sample, because the cells have to be cultivated in the laboratory. As this examination is usually carried out between the 14th and 18th week of pregnancy, it can be done at any time. If the test is carried out at the 21st week of pregnancy, the definitive result may not be available until the 21st week. week of pregnancy. The termination of a pregnancy at this time means that the birth has to be induced. The risk of a miscarriage following amniocentesis is low at less than 1%.
• Cordocentesis: Blood drawn from the umbilical cord is rare and only possible from the 18th week of pregnancy. week possible. The risk of a miscarriage is 1 to 2%. This procedure is mainly used in cases of suspected blood group incompatibility or foetal anaemia.

Parents can choose whether and which prenatal tests they want to have done. Before any examinations are carried out, they should be clear about what the tests involve and whether an abortion is an option for them at all.

In addition, certain risk factors have to be met for the costs of prenatal diagnostics to be covered by the health insurer.