Invasive Tests

What do they involve?
These are diagnostic tests that are performed to examine the chromosomes of the baby. The principal concern for most women undergoing these tests is the potential risk of miscarriage, which is approximately 1 % for both of the following procedures.

There are two types of test that can be carried out.

Chorionic Villus Sampling (CVS)
This is performed from 11 weeks and involves the removal of a small sample of
placental tissue. Local anesthetic is injected to numb the skin and a fine needle is
inserted through the abdomen into the placenta. An ultrasound scan is performed
throughout the procedure to guide the needle accurately and check the baby’s
heart rate.

Amniocentesis
This is performed from 15 weeks. A fine needle is passed through the abdomen and
amniotic fluid removed from around the baby. Again an ultrasound scan is performed to guide the needle accurately.

Results
The results are available in 2 stages. The preliminary result is available after 2 days and the final result after 2 weeks. We will contact you with these results and send a copy to your referring doctor. In the event that the result is not normal you will be fully counselled as to the implications and a referral to other clinicians e.g. geneticist can be made where appropriate.