Chorionic villus sampling (CVS)

Question

Hello!

My husband and I have a daughter with CF (mutation d508 and g551x).

Now we are thinking about having another child.

Which prenatal diagnosis is available? I read about chorionic villus sampling (CVS). Is CVS done or first an amniocentese?
Can this sampling really be performed in the 8th week of pregnancy? How long does it take to get the result? How reliable is it?

Many thanks for your answer.

Answer

Dear questioner,

A chorionic villus sampling (CVS) is usually done between the 10th and the 12th week of pregnancy. The optimal point in time is rather as of the 11th week of pregnancy since a certain amount of chorionic villi is needed. This is not always the case before the 11th week of pregnancy.
In general, for a molecular genetic analysis of a CVS a cultivation of cells is not necessary, as chorionic villi are rich in nuclei and therefore also in DNA. In a genetic laboratory, the analysis in case of known mutations takes 24-48h.
In practice, however, it can also last 10 days, until the result is available for the treating gynaecologist or the patient, as here time to send the material, the results and differences from laboratory to laboratory have to be taken into account. The result it then secure for the investigated mutation.

Amniocenteses should preferably be done as of the 15th week of pregnancy because a certain amount of amniotic liquor is needed, and this is only the case as of this point in time at the earliest.

Best regards,
Dr. A.-U. Stücker

01.09.2011