Chorionic villus sampling (CVS) is an antenatal procedure for prenatal diagnosis of chromosomal or genetic disorders in the fetus. It entails getting a sample of the chorionic villus (placental tissue) and testing it.
A transabdominal or transcervical approach is selected depending on the position of the placenta to avoid entering the amniotic cavity.
It is usually performed under ultrasound guidance and takes during the 10-12 weeks of gestation, earlier than amniocentesis (which is carried out as early as 14-16 weeks).
Potential risks
- miscarriage: 0.5-4% 1
- amniotic fluid leakage
- possible limb reduction defects: not proven in randomized controlled trials