Obstetric Invasive Diagnostic Testing

Chorionic Villus Sampling

This is a placental biopsy for checking the fetal chromosomes or/and other genetic tests. It involves passing a needle under ultrasound-guidance into the placenta and hence is associated with a small risk of miscarriage (0.2%). The procedure is usually performed transabdominally.

• Some urine in the bladder is preferable at time of procedure
• Local anaesthetic is give prior to the CVS and this is usually the most uncomfortable part of the procedure
• It is preferable to have someone to drive you home afterwards and that you rest for 24 hours following the CVS
• If you are Rhesus negative blood group then Anti-D medication will be given after the procedure

Amniocentesis

This is sampling the fluid from around the baby for checking chromosomes or other genetic tests. It involves passing a needle under ultrasound-guidance into the fluid around the baby and hence is associate with a small risk of miscarriage (0.1%).

• Some urine in the bladder
• is not necessary for this procedure
• It is preferable to have someone to drive you home afterwards and to rest for 24 hours after the amniocentesis
• If you are Rhesus negative blood group then Anti-D medication will be given after the procedure