Prenatal Diagnosis Program

Understanding Prenatal Tests

Prenatal tests are done for various reasons. Some tests occur at the start of your pregnancy to evaluate your health, but they do not provide any information about your baby. Most of these routine lab tests screen for infectious or sexually transmitted diseases or pre-existing conditions that could make yours a high-risk pregnancy. You and your doctor can take protective steps when you know these risk factors early. Examples of routine tests your obstetrician may order are:

• Blood type
• Complete blood count
• Hepatitis B and hepatitis C
• Human immunodeficiency virus (HIV)
• Rubella
• Sexually transmitted disease (STD)
• Tuberculosis
• Urinalysis
• Urine culture

Another type of prenatal testing is genetic screening, which checks for conditions that could affect the health of your unborn child. All pregnant women should be offered prenatal genetic screening, according to the American College of Obstetricians and Gynecologists. These tests are often painless and pose no risk to mother or child. The most common prenatal tests used for genetic screening are:

• Cell free fetal DNA test for Down syndrome, Trisomy 18 and Trisomy 13
• Ethnicity-based carrier screenings for cystic fibrosis, sickle cell anemia and Tay Sachs disease
• Quad screen for Down syndrome, Trisomy 18, open neural tube defects/spina bifida
• Ultrasound

Although a prenatal screening test can suggest a health condition in your unborn child, only more advanced testing can confirm it. Prenatal diagnostic tests are a higher tier of tests, designed to pinpoint specific health concerns. For example:

• Chorionic villus sampling takes cells from the placenta and analyzes the chromosomes or DNA to confirm certain genetic disorders in the baby.
• Amniocentesis analyzes amniotic fluid taken from a mother’s uterus to diagnose certain genetic disorders and confirm brain or spinal cord defects.
• Percutaneous umbilical blood sampling analyzes a sample of your unborn baby’s blood to identify fetal anemia.

These tests tend to be more invasive, and for that reason, they carry a slight risk to your unborn child. Our genetic counselors are available to explain the risks, benefits and limitations of these testing options.

Who should consider diagnostic genetic testing?

• Couples who have a family history of a birth defect or genetic condition
• Couples who have had multiple miscarriages
• Women who are 35 or older at the time of delivery
• Women with abnormal ultrasounds
• Women with abnormal serum screening that suggests certain birth defects
• Women who have been exposed to alcohol, recreational drugs, certain medications or infections

The Prenatal Diagnosis Program at Riley at IU Health offers highly skilled specialists in prenatal diagnosis. Our experts can help:

• Manage your pregnancy
• Determine the likely outcome of your pregnancy
• Plan for possible birth complications
• Anticipate health problems in your newborn
• Identify conditions that have implications for future pregnancies

Maternal-fetal physicians and genetic counselors evaluate women whose babies may be vulnerable to a birth defect or health condition. Our specialists use the latest screening and diagnostic tests to detect areas of concern. From the results, we can recommend plans for your pregnancy and delivery so you can make informed healthcare decisions. If you come to us through a referral from your obstetrician, we maintain an open line of communication to keep your physician informed.