Prenatal diagnostic tests (incl. amniocentesis, chorionic villous sampling) Flashcards
What is CVS?
– performed 10-13/40 (i.e. week 12)
1% miscarriage rate
How does CVS happen?
o USS-guided needle aspirate of placental tissue
o Foetal viability confirmed and anti- RHD given to RH-neg women (sensitising event)
What is amniocentesis?
USS guided needle
1% miscarriage rate
When can you do amniocentesis?
performed ≥15/40
How does amniocentesis happen?
o USS guided needle, avoid entry of placenta, small aspirate of amniotic fluid
o Foetal viability confirmed and anti-RhD given to Rh-neg women (sensitising event)
What are the indications of CVS and amniocentesis?
o Demonstrated risk at antenatal screening
Suspected foetal anomaly on USS
o FHX of inherited disorder
Known carrier status for inherited disorder
o Previous pregnancy with chromosomal disorder
Increased maternal age
What are the complications of CVS/ amniocentesis?
o Generic: bleeding, infection, damage to local structures, procedural failure
o Abdominal pain
o Miscarriage (both CVS and amniocentesis at 1%)
o Chorioamnionitis
o Limb abnormalities if CVS performed before 10/40
