Prenatal examinations provide more certainty

Prenatal diagnostics are examinations done before your baby is born. Not all pregnancy examinations fall under prenatal diagnostics however. Strictly speaking, the regular urine exams, antibody tests on the mother’s blood and ultrasound examinations are not part of these. Prenatal diagnostics are more for detecting the individual genes of certain hereditary diseases, such as chromosomal abnormalities or rare diseases that run in the family. 

Long before your baby is born, the prenatal diagnostics will give you reliable results.

In order for the gynaecologist to determine the chromosomes of the unborn child, they will need cells from the child. This is why an invasive test is necessary. The gynaecologist will take some tissue from the placenta using a needle (chorionic villus sampling) or do an amniocentesis test. Afterwards, they will analyse the chromosomes in the cells, or in special cases, the genes as well. Only in this way will the gynaecologist be able to tell if there is a congenital disease, chromosomal abnormalities or a genetic defect.

Non-invasive tests have been developed to avoid risky procedures. This means no surgical procedure is necessary. The doctors analyse various factors and use them to create an overall picture. During the first trimester, they can detect whether your child is at increased risk of chromosomal abnormalities. The following factors are used in the analysis:

• The age of the pregnant woman
• Certain hormone levels during the blood test
• Findings from several ultrasound examinations

There are several non-invasive diagnostic blood tests (NIPT) approved in Switzerland. Laboratories offer blood tests for foetal DNA. These tests can detect foetal chromosomal abnormalities directly in the mother’s blood already from the 11th week of pregnancy. Trisomy 21, also known as Down Syndrome, is one of the most common abnormalities.

In contrast to the chorionic villus sampling and amniocentesis, there is no risk of a miscarriage during the first trimester test.

In the first step, the gynaecologist will conduct a first trimester screening. If the ultrasound examination and the mother’s blood count are at an increased risk for chromosomal abnormalities, then an NIPT, or an invasive examination, can be performed depending on the ultrasound findings and how high the risk is. If, however, the first trimester screening shows a low risk, then no further examinations are necessary.