Auckland Obstetric Centre
This test is usually done at between 15 and 17 weeks of pregnancy. A needle is passed through your abdominal wall into the fluid around baby - an ultrasound scan is used to guide the needle and make it a safe procedure for baby. Local anaesthetic can be used to make it a more comfortable procedure for you. A small amount of fluid is drawn off. Within this fluid are some of baby's skins cells that can be cultured in the laboratory to check the chromosomes.
It can take 10 to 14 days to get a result from this test. A more rapid test (called FISH) is available that can check for Down syndrome within 24 to 48 hours is also available but at an additional cost - the doctor performing your amniocentesis can discuss this option with you.
Amniocentesis is a quick procedure taking about 10 to 15 minutes to set up and only a few minutes to do. You are welcome to bring your partner or a support person along and should plan to have a quiet 24 hours after the test. It does have a small risk of miscarriage. For every 150 women having an amniocentesis one woman will miscarry as a result of the procedure.
You can download our information leaflet on medical and screening tests in early pregnancy here.