What is Amniocentesis?

This involves taking a sample of amniotic fluid, which surrounds the baby. Floating in the fluid are some of the cells from the baby's skin, they can be analyzed.

When can I have Amniocentesis?

An Amniocentesis is usually performed at around 15 weeks of pregnancy, but can be done at later gestations. 

How is it performed?

Under ultrasound guidance a fine needle is passed through the abdominal wall and into the amniotic fluid. The tip of the needle can be seen at all times and moved if the baby happens to come close.

How long does the result take?

The result of the baby's chromosomal makeup is usually available after 11 days. A new laboratory technique called FISH (Fluorescent In-Situ Hybridisation) can give a result on the 5 major chromosomes involved in abnormality within 48 hours, and usually within 24 hours. Often a small amount of sample is sent for estimation of the alpha-fetoprotein (AFP) level, which gives an indication of the risk of spinabifida.

Is there a risk to my pregnancy?

Yes. There is a background risk of miscarriage at 15 weeks of pregnancy of around 1%, and if an amniocentesis is performed there is an additional risk of 0.5%. There are no other risks involved in the test.