An Overview of Amniocentesis

Amniocentesis, also known as amniotic fluid test or AFT, is a form of prenatal test that allows Dr. Dennis Eisenberg and his OBGYN team to gather vital information about a baby’s health. The most common reason to perform this test is to determine whether a baby has a certain chromosome abnormality or genetic disorder, such as Down syndrome. The test is typically performed when a pregnant woman living in the Plano, Frisco and Dallas, Texas area is between 14-20 weeks and receives an abnormal triple test (AFP, hCG and Estriol) result.

What is an Amniocentesis?

An amniocentesis is defined as a procedure that removes amniotic fluid from the uterus for testing and/or treatment. Amniotic fluid is the fluid that surrounds the baby and protects him/her during the pregnancy. This fluid contains important structures such as fetal cells and chemicals created by the baby during development.

An amniotic fluid test (AFT) utilizes an ultrasound as a guide to determine a safe spot for the needle to enter the amniotic sac. Once the needle is inserted, a sample of the fluid is harvested. The whole procedure from beginning to end takes less than one hour.

The harvested amniotic fluid is then sent to a laboratory for analysis. Women can expect their results in as little as a few days to as long as a couple weeks, depending on the laboratory selected.

Why is an Amniotic Fluid Test (AFT) Performed?

An amniocentesis is usually performed between 14-20 weeks to detect chromosome abnormalities, genetic disorders and neural tube defects. The most common chromosome abnormality is Down syndrome. The most common genetic disorder is cystic fibrosis. The most common neural tube disorder is spina bifida.

An amniotic fluid test may be recommended in the third trimester for a variety of reasons. The procedure can help determine if a baby’s lungs are mature enough for the baby to breathe on its own, if a uterine infection is present or if membranes have ruptured prematurely. Amniocentesis also has the ability to help determine the severity of fetal anemia in babies with Rh disease.

Prior to delivery, the procedure can also be used for paternity testing. DNA is collected from the amniotic fluid of the baby and the father to compare results. It is reported the results are 99% accurate.

Much like utilizing AFT for an accurate paternity test, the procedure produces high levels of accuracy (98-99%) when detecting genetic disorders, neural tube defects and chromosome abnormalities.

An amniocentesis is considered safe for the mom and baby, but there are some risks involved since it is considered invasive. Although rare, the risk of miscarriage ranges from 1 in 400 to 1 in 200. A miscarriage can occur from the water breaking, an infection in the uterus or labor being induced prematurely.

For additional resources on amniocentesis, or to determine if you require an amniotic fluid test (AFT), please contact the Plano, Frisco and Dallas, Texas area office of Dr. Dennis Eisenberg.