Prenatal Diagnosis and Genetics Program

Thankfully, most babies are born healthy. However, approximately 3% of all babies will have some type of birth defect. A “birth defect” is a health problem or physical change that is present in a baby at the time he or she is born. This 3% chance for a birth defect is often referred to as the “background rate for birth defects”. Some pregnancies are thought to have a risk for birth defects that is higher than the background rate. This could be due to a patient’s personal or family history, an abnormal screening test, medication or drug exposure or parental age. Knowing that the baby has a particular type of birth defect before delivery can improve the outcome for some babies.

Some birth defects have a specific known cause, such as a chromosome abnormality, a single gene mutation, or a particular environmental exposure, and some are caused by a combination of environmental and genetic factors. However, the cause of many birth defects cannot be determined.

At OSU we offer many options for prenatal screening and diagnosis. Screening options include first-trimester screening, quad screening and ultrasound. Diagnostic options include chorionic villus sampling (CVS), amniocentesis and fetal blood sampling.

We can also offer carrier screening for many genetic conditions, depending on your personal risk factors.

Your healthcare provider can discuss the various screening and testing options with you or you may wish to contact one of our genetic counselors. Our genetic counselors can help determine whether you have an increased risk for certain birth defects and help you determine what screening and/or testing options might be most helpful.

Genetic Counseling
Prenatal genetic counselors work as members of a health care team, providing information and support to families who may have an increased risk for having a child with a birth defect or genetic condition. They have advanced training in genetics, the study of how traits are passed from parents to children.

When you meet with a prenatal genetic counselor you will discuss your pregnancy and family history. Since we will be reviewing your family history, you may find it helpful to talk to your parents or other relatives prior to your appointment.

The U.S. Surgeon General has a free online family history tool that helps you create a family history diagram that some patients choose to print out and bring to their appointment. If you would like to try this online program, please visit the following Web site:
https://familyhistory.hhs.gov/

Depending on your particular circumstances, the genetic counselor may also review some specific screening and testing options that are available. A prenatal genetic counselor can also help provide valuable resources or referrals if your baby is found to have a birth defect. Most of the time, the genetic counselor is able to provide reassurance that your pregnancy is going well.

There are many reasons to meet with a genetic counselor. Some go because of a family or personal history of a genetic condition. Others see a genetic counselor because they have had trouble getting pregnant or because they have had several miscarriages or infant deaths. Some of the other common reasons you may be referred to a prenatal genetic counselor include:

You will be 35 years of age or older when you deliver. This is because the odds of having a child with a chromosome change, such as Down syndrome, increase with maternal age.
You have had a screening test (such as first trimester screening or quad screening) (dead link) that revealed an increased risk for a chromosome change or spina bifida.
You have had an ultrasound that has found a difference (or possible difference) in the baby’s development. Some examples of physical changes that can be found on an ultrasound include cleft lip, spina bifida and heart defects.
You and your partner are close relatives, such as first cousins.
You are concerned about genetic conditions that occur more frequently in certain ethnic or racial groups. For example, couples of African descent have a higher chance of having a child with sickle cell anemia; couples of European Jewish (Ashkenazi) or French Canadian descent have a higher risk for Tay-Sachs disease; and couples of Italian, Greek, or Middle Eastern descent have a higher chance to carry the gene for thalassemia, a blood cell disorder.