Q: What is amniocentesis?

A: Amniocentesis is a prenatal procedure in which a small amount of amniotic fluid (the fluid that surrounds and protects a baby during pregnancy) is removed from the uterus for testing or treatment. This fluid contains fetal cells and various chemicals produced by the baby (and shed during growth) and other substances, such as alpha-fetoprotein. The fluid is then sent to a laboratory for analysis.

Q: Why is an amniocentesis performed?

A: Amniocentesis is performed to look for certain types of birth defects, such as Down’s Syndrome. Amniocentesis can also detect certain neural tube defects (diseases with which the brain and spinal column don't develop properly) such as spina bifida and anencephaly.

Q: Can anyone have an amniocentesis?

A: Because amniocentesis presents a small risk for both the mother and her baby, the prenatal test is generally offered to women who have a significant risk for genetic diseases, including those who:

• Have an abnormal ultrasound.
• Have a family history of certain birth defects.
• Have previously had a child or pregnancy with a birth defect.
• Will be 35 years of age or older at the time of delivery.

Q: When is amniocentesis performed?

A: If your doctor has recommended an amniocentesis, the procedure is usually scheduled between the 15th and 20th week of pregnancy although it can also be done during the third trimester of the pregnancy to determine if the baby's lungs are mature enough for delivery in cases where an early delivery may be warranted.

Q: How accurate is amniocentesis?

A: About 99.4%. Complications, including miscarriage, occur in one in 200-500 procedures.