How the test is performed
Amniocentesis is a procedure to withdraw a small amount of amniotic fluid (the fluid surrounding a developing fetus) from the uterus. The amniotic fluid can be tested for certain kinds of birth defects.
Amniocentesis is performed in your doctor’s office or hospital clinic as early as 15 weeks into your pregnancy,1 counting from the first day of your last menstrual period.
An ultrasound is used to guide the physician as the amniotic fluid is withdrawn. This amniotic fluid contains cells that are shed from the developing fetus and the sample is sent to the laboratory to test for certain genetic diseases and birth defects.