CVS is an important prenatal diagnostics test:under ultrasound guidance, an 18-20 Gauge needle is inserted through the abdomen to collect a small sample of chorionic material which will then be analysed.
The test can be performed after 10 weeks of pregnancy; it is an outpatient procedure and no anaesthesia is needed.
Preliminary test results are usually available in 7 days (direct analysis method); final test results are available in about 20 days (cultural method).

CVS purposes and indications:
 
FETAL CARIOTYPE:
 
• maternal age = 35;
 
• previous fetal aneuploidy;
 
• chromosomal rearrangements in parents;
 
• family history of aneuploidy;
 
• positive first trimester screening test;
 
• fetal malformations detected during ultrasound scan;
 
• sex determination for X-linked genetic defects;
 
FETAL DNA ANALYSIS:
 
• genetic disorders;
 
• congenital metabolic disorders;
 
• assessment of biological paternity;
 
BIOCHEMICAL TESTS:
 
• congenital metabolic disorders (unknown mutations);
 
OTHER INDICATIONS:
 
• previous birth of babies with malformations;
 
• previous multiple miscarriages;
 
• previous intrauterine fetal death.