Optional genetic testing

The American College of Obstetrics and Gynecology (ACOG) recommends that all patients, regardless of age, should be offered both antenatal screening and diagnostic testing for fetal chromosomal abnormalities.

It is up to you whether or not you have any testing done. Talk with your doctor if you have any questions about genetic testing.

Below is some general information to help you understand the different types of testing. We also have educational brochures for you in our office that further define genetic testing.

Antenatal screening

Antenatal screening tests detect whether a woman who may be at higher risk of having a baby with chromosomal abnormalities like Trisomy 21 (Down Syndrome), Trisomy 13, Trisomy 18, and other conditions.  These tests identify an increased risk of fetal genetic abnormalities or certain birth defects, and do not actually diagnose a specific condition. 

  • First Trimester Screen (sometimes called a “First” Screen)
  • Second Trimester Maternal Serum Screen (sometimes called a “Quad” Screen)
  • Alpha Fetoprotein (sometimes called the AFP).  
  • Free Fetal DNA

For all of our patients, we do perform ultrasound for fetal evaluation which can detect some genetic abnormalities as well.

Types of diagnostic testing

Diagnostic testing samples fetal cells to determine the fetus’s actual chromosome make-up and to confirm if the fetus is genetically normal. There are two types of testing:

  • Chorionic Villus Sampling (CVS)
  • Amniocentesis

Chorionic Villus Sampling (CVS)
This is a test done between 10 and 14 weeks of pregnancy where a very small sample of the placenta is removed through a small needle.  The cells in this sample help determine your baby's chromosomes. The test does carry a small risk of miscarriage of about 0.5%.

Amniocentesis
This is a test done after 15 weeks of pregnancy where a small needle removes a small amount of the fluid from around the baby. The cells in this sample helps determine your baby's chromosomes.  The test does carry a small risk of miscarriage of about 0.2-0.3%.