“CVS and amniocentesis are two procedures, generally conducted by obstetricians, which make it possible to collect fetal cells, of the placenta in the case of CVS and of the amniotic fluid in the case of amniocentesis “, explains Faustina Lalatta, Head of the Medical Genetics Unit at the Mangiagalli Clinic of the Milan Polyclinic. “Both procedures are defined invasive and are performed through the maternal abdomen under ultrasound control”, adds the specialist.
Expert advice in the video
What are the differences between CVS and amniocentesis?
Villocentesis is very useful for women with high genetic risk because it is performed early, that is, as early as the eleventh week of pregnancy. While amniocentesis requires a longer wait to be performed: it can be performed from the fifteenth week. Through the villocentesis it is also possible to take quite a lot of placental tissue and having an abundance of genetic material available: we always use it when we have to test for hereditary diseases. When the woman requires only thechromosomal examination, then let’s say that there is not this big difference: the amniocentesis is a little more reliable because it has fewer doubtful cases.
When is it necessary to do them and on the basis of what criteria is it better to do one or the other?
To perform an invasive procedure it has always been said that a good reason is needed, that is what we call a ‘clinical indication. The indication is the presence of a increased risk which can derive from different circumstances: the most common and best known risk is thematernal age over 35 years. But there are also others: for example those derived from the presence in the family of hereditary diseases; whether the parents – one or the other or both – are healthy carriers of genetic transmissible diseases; or, and this is an indication that it has expanded a lot, a ‘abnormal ultrasound, or a ‘early ultrasound, for example the one you do at the Bi-test, but also later, with themorphological ultrasound. All these situations, which lead to an increased probability that the child does not have a normal chromosomal makeup, lead to the debate on whether to do amniocentesis or CVS.
How to deal with this choice in the best way?
As always, I say the antidote to cope well with him prenatal exams, therefore even with the right balance and the necessary serenity, it is to prepare. There are two different situations: families who know they have risks – and there it is inevitable to prepare because you know your situation and already discuss in advance what the path of prenatal diagnosis will be, and you have the strength and help to be able to do so. to deal with – and then there is also a situation that can really concern anyone, for which we must prepare ourselves, and these are the unexpected findings. We always take the example of Bi-test, which is used a lot: if it is alarming, it will impose a series of quick decisions on the woman and the couple, which must be thought about in advance. So, I always say, think of the worst in order to enjoy a normal situation well.