Amniocentesis is a test that may be performed during pregnancy. It involves use of a needle to withdraw a small amount of fluid from around the baby. The test is usually performed after the 15th week of pregnancy. Amniocentesis can rule out chromosome problems such as Down syndrome and open neural tube defects such as spina bifida (open spine) and anencephaly (open skull).
When there is a known family history of a specific genetic condition, including sex-linked disorders such as hemophilia and metabolic diseases such as Tay-Sachs disease, amniocentesis may be able to provide additional information.
Preparation
- As with a regular ultrasound, a full bladder is needed for this test.
- Begin drinking a large amount (at least three to four glasses) of liquid (water, tea, pop, etc.) One hour before the test
- Do not go to the bathroom until the test is completed
Procedure
- You will lie flat on an examination table
- The doctor uses ultrasound to locate the amniotic fluid in the sac surrounding the baby
- The doctor inserts a needle to withdraw a small amount of amniotic fluid for testing
- The amniotic fluid will be sent to the lab for genetic testing and you will be notified of the results
For information about obstetrics and gynecology services at West Penn Allegheny health System:
AGH High Risk Obstetrics and Maternal-Fetal Medicine Services
WPH Obstetrics and Gynecology Services
WPH-Forbes Women's Health
Last Updated: February 26, 2009