Genetic amniocentesis is generally performed when a woman is at least 15 weeks pregnant. Your doctor will recommend an amniocentesis if possible birth defects are found on the ultrasound or you are at an advanced maternal age. During this test, amniotic fluid will be removed from the uterus for testing.
First, you will need to get an ultrasound so your doctor can determine where the pocket of amniotic fluid is located. Once it is located, a small sample of fluid is taken with a syringe to be tested in a lab. The procedure is safe, with less than one out of 750 procedures resulting in the risk of miscarriage.