AMNIOCENTESIS is a fundamental exam in prenatal diagnosis:Under ultrasound guidance, a 20-22 Gauge needle is inserted through the abdominal wall and uterus into the amniotic sac in order to obtain a sample of amniotic fluid that will then be analysed.
The test can be performed after 15 weeks of pregnancy; it is an outpatient procedure and no anaesthesia is needed. Preliminary test results are available in 3 days (QF-PCR); final test results are available in about 20 days (cultural analysis method).
 
Amniocentesis purposes and indications:  
 
FETAL CARIOTYPE:
 
• maternal age = 35;
 
• previous fetal aneuploidy;
 
• chromosomal rearrangements in parents;
 
• family history of aneuploidy;
 
• positive second trimester screening test;
 
• fetal malformations detected during ultrasound scan;
 
• CVS mosaicism;
 
• sex determination for X-linked genetic defects;
 
DNA ANALYSIS:
 
• suspected maternal-fetal infectious disease (Cytomegalovirus, Toxoplasmosis, German measles-Rubella; Parvovirus B19): using qualitative PCR;
 
• fetal Rh testing (also on maternal blood after 9 weeks);
 
• genetic disorders;
 
• congenital metabolic disorders;
 
ESAMI BIOCHIMICI:
 
• congenital metabolic disorders;
 
• neural tube defects.