| CVS (Chorion Villus Sampling) |
12 to 14 Weeks of Pregnancy Click on a question or scroll down to take you to the answer.
Too much information? Click here for a quick guide to CVS.
What is a CVS?
What is a CVS? The sample is then analysed in a Genetics Laboratory to diagnose any genetic abnormalities of your unborn baby. Because this tissue (villi) will eventually form your placenta genetic analysis of the sample will give the same result as if the fetus itself were examined.
Why would I need a CVS? However you may wish to have a CVS performed for your own peace of mind. The choice about whether to have a Chorion (or Chorionic) Villus Sampling or not is up to you. More information on Down Syndrome Screening and diagnostic tests can be found on our About Down Syndrome Screening page.
What is usually diagnosed from a CVS? A Chorion (or Chorionic) Villus Sampling can also used to obtain samples for Pre-Natal Paternity Testing.
What additional genetic disorders can be diagnosed from a CVS? Genetic testing can also be performed for other identifiable problems at additional cost. These supplemantary tests can be included if there is a family history or other children have been born with the condition. A consultation with one of our Fetal Medicine Specialists or a Consultant Geneticist will be necessary before proceeding with any of the following additional tests:
What happens during a CVS? During the CVS the consultant will pass a fine needle through your tummy into the placental tissue on the outside of your pregnancy sac. Although this may sound frightening to some in reality the procedure is usually very straighforward, and is performed under continuous ultrasound vision to avoid any threat to your baby. A local anaesthetic is applied before the needle is inserted to ensure that the CVS carries little discomfort. The doctor will then draw up a tiny sample of your developing placenta (villi) via a syringe into some sterile pink media. Much of the appointment time is taken up with preparation and counselling. The actual Chorion (or Chorionic) Villus Sampling procedure only takes one or two minutes to perform and is usually over before you realise it.
When can I have a CVS? We cannot perform a Chorion (or Chorionic) Villus Sampling before 11 weeks because the chances of miscarriage are much higher.
What if I have missed the window for having a CVS?
What are the risks when having a CVS? Because a CVS is performed during early pregnancy when most miscarriages are more likely to occur naturally the risk may be higher than if an Amniocentesis is performed in later pregnancy.
What are the success rates of your consultants performing the CVS?
How is the sample from a CVS analysed? The sample and it is analysed using a process known as PCR (Polymerase Chain Reaction) to obtain a preliminary result. The specimen is then set up for karyotyping in a culture which usually produces an identical result to the intial PCR.
When will I receive the results of my CVS? Results from a full analysis of other requested chromosomal anomalies can also take up to 2 weeks. Most genetic testing produces a definite answer, however in 1 in 100 of cases the results may prove inconclusive so further consultation or testing may be required.
Do I need to make any preparations before a CVS? Please bring written confirmation of your blood group to your CVS appointment. If you are unable to provide documented evidence of your blood group you will need to have a blood type test performed at additional cost. You do not need to fast before a Chorion (or Chorionic) Villus Sampling although you should arrive with a full bladder to allow clear initial imaging.
Are you able to tell me the gender of my baby from a CVS? If you'd like to know the gender of your baby please tell the consultant during your appointment as gender isn't routinely reported unless requested. Please note that we will not perform a Chorion (or Chorionic) Villus Sampling solely for the purposes of Gender Identification.
Anything else I should know about the CVS? Unfortunately there is nothing that can be done to predict when this might happen or to avoid it. The only solution is to wait until at least 16 weeks gestation when an Amniocentesis can be performed. On the odd occasion where this occurs you will be charged for our professional scanning and consultation time which will be in addition to the cost of the usual Chorion (or Chorionic) Villus Sampling fee.
What is my next scan after the CVS?
How do I book a CVS? The procedure is only performed by qualified Consultants on certain days so please be prepared to be flexible with your booking date. Because of the preparation required for this procedure we usually ask for a £100 deposit to secure a Chorion (or Chorionic) Villus Sampling appointment. |
