Prenatal - Genetic Testing

Genetic Testing

During the course of your pregnancy, you may be offered prenatal genetic testing.  In addition to the information you receive from our providers and nurses, this page is intended to serve as an extra resource.  We are happy to answer any questions you may have about genetic testing.  If we can be of any assistance, please do not hesitate to contact us.

What is Prenatal Genetic Testing?

Prenatal genetic testing refers to tests that are done during pregnancy to either screen for (see below) or diagnose a birth defect.  The goal of prenatal genetic testing is to provide expectant parents with information to make informed choices and decisions.  Genetic testing also assists our providers in providing the best care and management of your pregnancy.  It is important to remember that all genetic testing is optional. 

There are two types of prenatal genetic tests: screening tests and diagnostic tests.

  1. Screening tests do not diagnose a birth defect, they only determine if a fetus is at high or low risk for a specific condition.  Examples of screening tests:
    • First Trimester Screening (nuchal translucency)
    • Cystic Fibrosis Carrier Screening
    • Modified Sequential Screening
  2. Diagnostic tests can diagnose certain fetal conditions with a high degree of accuracy.  Examples of diagnostic tests:
    • Amniocentesis
    • Chorionic Villus Sampling (CVS)

Who should have prenatal genetic testing?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women, regardless of their age, be offered screening for Down Syndrome (First Trimester Screening).  With the exception of the First Trimester Screening, genetic testing is generally offered to couples or individuals who are identified as being at risk for a particular genetic condition. 

What are the Prenatal Genetic Tests that I may be offered?

First Trimester Screening

This is a combination of a blood test and ultrasound examination to help identify babies who may have Down Syndrome, Trisomy 18 or Trisomy 13.  This test is performed in our office. 

Modified Sequential Screening

This test is a follow up to the First Trimester Screening (Ultra-Screen).  It may be recommended to some patients, in order to provide more information to those women that are considered higher risk on the first trimester screening.

Cystic Fibrosis Carrier Screening

This blood test is used to tell women and men if they are carriers for Cystic Fibrosis.

Click here to read more about Cystic Fibrosis Screening.

Chorionic Villus Sampling (CVS)

This test involves obtaining a sample of the tissue surrounding the sac where the fetus develops.  A sample of the cells from this tissue provides chromosomes and other material that may then be tested to diagnose chromosomal abnormalities, genetic birth defects, and other conditions.

Click here to view the University of Rochester’s Chorionic Villus Sampling (CVS) brochure.


During this test, an obstetrician will use a thin needle to remove a small amount of amniotic fluid (the fluid surrounding the fetus).  This fluid will be tested for chromosomal abnormalities, genetic birth defects and other conditions.

Click here to view the University of Rochester’s Amniocentesis brochure.

AFP+ Screening

This blood test is used to screen for birth defects.

Click here to view the University of Rochester's AFP+ Screening brochure.


Again, please remember that we are here to help.  If we can answer any questions for you, please do not hesitate to contact us.