At the OHSU Center for Women’s Health, we can help you learn about your baby’s health and development. We offer many tools to determine if your baby is at risk for genetic health conditions and birth defects.
We provide complete care, from counseling to an array of testing options. We offer:
- Specialists who work together to create the best possible plan for your goals.
- Certified genetic counselors to guide and support you in your decisions.
- On-site labs for faster results for most tests.
- Advanced genetic tests, imaging and fetal care for diagnosis and treatment.
What is prenatal screening and genetics?
We offer a full menu of screening and diagnostic options to learn about your baby’s health, and risk for certain birth defects and genetic disorders.
Not all health issues can be found before delivery. But early testing can help you and your providers adjust your care plan for the best possible outcome.
Which test you want (if any) is up to you. If you want guidance, our genetic counselors can help you decide which tests are right for you.
Types of prenatal testing
We offer two types of prenatal tests: screening tests and diagnostic tests. Screening tests show if your baby is at risk for an inherited disease or condition. Diagnostic tests show if your baby has certain inherited diseases or conditions.
Screening tests can show your risk for certain issues, but they can’t tell you for sure if your baby is healthy. They generally pose little or no risk to your pregnancy.
What this is: Simple blood or saliva tests to screen you and your partner for recessive disorders.
What it looks for: Carrier screening looks for recessive conditions. These are inherited genetic diseases that can happen even in families with no history of the disease.
With one test, we check for many recessive conditions including:
- Cystic fibrosis
- Spinal muscular atrophy
- Sickle cell disease and other blood disorders
- Fragile X syndrome
- Tay-Sachs disease
When you have the test: Any time before or during pregnancy
What happens next: If the test finds that you or your partner are a carrier for a recessive condition, we will offer you genetic counseling. If you are already pregnant, we may also offer diagnostic testing.
What this is: A blood test, also called NIPT (non-invasive prenatal testing), that analyzes the DNA (genetic material) from your pregnancy in your blood.
What it looks for: It can tell us the likelihood that your baby will have chromosomal abnormalities such as Down syndrome, trisomy 18, trisomy 13 or sex chromosome disorders.
Accuracy: If your baby has Down syndrome or trisomy 18, this test has a 99% chance of finding it. It can detect more than 90% of cases of trisomy 13 and sex chromosome disorders. The false-positive rate is less than 1%.
When you have the test: Available starting at 10 weeks of pregnancy.
What happens next: If the test finds a condition or an increased risk, we will offer you genetic counseling and diagnostic testing. Tests could include chorionic villus sampling (CVS) or amniocentesis (see below).
The test we use: Sequential screening is a combination of blood tests and ultrasounds that helps us estimate your risk of chromosomal issues and birth defects.
What it looks for:
- Down syndrome, the most common genetic developmental condition in the U.S.
- Trisomy 18, a medical and developmental disorder caused by an extra 18th chromosome.
- Spina bifida, a birth defect of the spine.
Accuracy: If your baby has Down syndrome or trisomy 18, these tests have a 90% chance of finding it. The rate is 80% for spina bifida. The false-positive rate is up to 5%.
When you have the screening:
- Ultrasound and first blood test: 11 to 13 weeks of pregnancy.
- Second blood test: 15 to 21 weeks of pregnancy.
What happens next: If a test finds a condition or an increased risk, we will offer you genetic counseling, more ultrasound screening and/or diagnostic testing.
If a screening test or your family history shows your baby is at risk, you can choose to have a diagnostic test. These tests can tell you if your baby has a specific problem. They pose a small risk to your pregnancy.
What this is: We send a small sample of your placenta to a lab for testing and analysis. Your doctor will use ultrasound images to guide a small, flexible tube through your vagina and cervix to take the sample from inside your uterus. The tube does not touch your baby or enter the amniotic sac. We also can take the sample with a needle through your belly.
What it looks for: Chromosomal conditions such as Down syndrome and trisomy 18, and genetic disorders such as cystic fibrosis and Tay-Sachs. Results are 99.9% accurate.
Risks: There is about a 1% risk of complications, including bleeding, cramping, infection or miscarriage.
When you have the test: 11 to 14 weeks of pregnancy.
What happens next: If the test finds evidence of a genetic disorder or birth defect, your care team will talk with you about options, which may include more imaging. Some conditions can be treated through the Fetal Care Program at OHSU Doernbecher Children’s Hospital.
What this is: Your doctor takes a sample of the amniotic fluid that surrounds your baby so the fluid can be analyzed. The doctor uses ultrasound to guide a needle into your abdomen and uterus, without touching the baby.
What it looks for: The test can diagnose chromosomal and genetic conditions such as Down syndrome, cystic fibrosis and sickle cell disease. It also can detect some birth defects such as spina bifida. Results are 99.9% accurate.
Risks: There is less than a 0.3% risk of complications, including bleeding, cramping, infection or miscarriage.
When you have the test: 16 to 24 weeks of pregnancy.
What happens next: If the test finds a genetic health problem, your care team will talk with you about your options. We work closely with specialists in OHSU Doernbecher Children’s Hospital’s Fetal Care Program to care for genetic disorders and birth defects before and after delivery.
Our team of experienced genetic counselors can help you understand your risks. They can also help you choose the best tests for you and your family.
You can have most prenatal screening and genetic tests without seeing a genetic counselor. If you want more guidance and support, our genetic counselors are available to meet with you.
Our counselors are licensed care providers with Master’s degrees, and are certified by the American Board of Genetic Counseling. The team includes specialists in infertility and newborn care.
What genetic counselors can help with
Our genetic counselors are here to provide education, support and counseling about genetic conditions and testing. They can help you:
- Weigh your genetic risk factors before or after you get pregnant.
- Understand your testing options and the results.
- Decide which tests are right for you.
- Choose the best tests for your background and family history.
- Coordinate and schedule your tests with your prenatal care provider.
What to expect
At your appointment, your genetic counselor will:
- Talk with you about your goals. For instance, you may want to test your baby for a specific condition. Maybe you want to avoid a certain test. Some people want to know for sure if their baby has a genetic issue before delivery. Others are comfortable with more uncertainty.
- Take a complete family history of any genetic issues to help assess your risk. It can be helpful to ask your relatives in advance about any birth defects, cognitive (thinking) issues or other conditions. Your counselor will talk with you about any higher risks based on your personal background.
- Coordinate testing with your prenatal care provider.
- Review the results of any ultrasound scans and screening tests, including what they mean. You will often need more testing to get an accurate diagnosis.
- Talk with you about options for more testing, including the risks and benefits of each test.
When you might see a genetic counselor
You may benefit from seeing a counselor if you:
- Will be 35 or older when your baby is born.
- Have another child with a chromosomal abnormality, birth defect or other genetic condition.
- Have a family history of a birth defect or genetic disorder.
- Had an ultrasound scan or screening test that indicates higher risk.
- Have been exposed to medication, drugs or substances during your pregnancy that could increase risk.
- Want to be screened for a genetic condition that is more common in your ethnic background.
- Are unsure about testing or want a more detailed discussion about your options.
Ultrasound: We offer advanced ultrasound and fetal MRI (magnetic resonance imaging) to screen for and diagnose prenatal conditions.
Fetal care: If your baby has a birth defect or other genetic condition, you may be referred to the Doernbecher Fetal Care Program. Our expert team offers the most advanced care for you and your baby in Oregon.
- What tests might I need during pregnancy? Eunice Kennedy Shriver National Institute of Child Health and Human Development
- Prenatal Testing, MedlinePlus, U.S. National Library of Medicine
- Making Decisions about Prenatal Tests for Birth Defects, Journal of Midwifery & Women’s Health
- What is genetic testing? Genetics Home Reference, U.S. National Library of Medicine
- Genetic Disorders: Frequently Asked Questions, American College of Obstetricians and Gynecologists.
- Prenatal Tests, March of Dimes