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We have already spoken of screening that are performed during the first trimester of pregnancy.
Now I’d like to talk about the tests that are done in the second trimester of pregnancy, to detect signs of so-called soft markers, which allow us to predict, to some extent, the possibility that our child is suffering from chromosomal defects.
You have already heard of soft markers. What are they?
These are structural features that are identified through ultrasound, which in itself is not a problem, but can be signs of a change in the number of chromosomes. The most common are:
These can be found in approximately 5% of all pregnancies in the second trimester and are often the cause of much anxiety for parents.
It is very difficult to determine exactly what impact these markers in chromosomal abnormalities, because we have not yet enough data to determine.
If we take them separately, the risk of chromosomal problems is low. But if there are more than one or there are other structural defects, the risk is very high.
We must not regard them as a screening test for chromosomal abnormalities because the majority of fetuses with Down syndrome have, in ultrasound, a normal appearance.
The best time to identify the soft markers is in ultrasound in the second trimester of pregnancy (between the 16th and 18th week).
Those listed above are not the only signs. We find also the following:
Technological development allows us to identify these signals, however, make anxious parents, often in vain, because most often disappear before birth without consequences.