Prenatal Screening and Diagnosis

What is prenatal screening & diagnosis?

Prenatal screening & diagnosis is the use of one or more tests to determine if a developing baby has a health problem before birth. These health problems may include chromosome abnormalities, such as Down syndrome, or single gene disorders, such as cystic fibrosis. Not all health problems can be detected before delivery.

Many steps may be involved in prenatal screening & diagnosis and not everyone will choose the same path depending on their beliefs and/or their concerns. In general, there are two broad categories of tests that are available:

Screening Tests

Screening tests gather information about the possibility of a health problem (such as a chromosome abnormality or birth defect) in the developing baby during pregnancy. Screening generally posses no risk to the pregnancy and may include:

• First trimester ultrasound

• First trimester ultrasound and blood test

  Also called the "FirstScreen" or "Ultrascreen" and the "Sequential Screen"
  See "Options for First Trimester" Screening Handout for detailed information. Also available en español.

• Second trimester ultrasound

• Second trimester blood test called the "Quadruple marker screen"

• A detailed family history by a genetic counselor

  See information about our genetic counselors.

Diagnostic Tests

Diagnostic tests are able to accurately tell whether a developing baby has a specific health problem. There is a small risk to the pregnancy if these tests are performed. Diagnostic tests include:

• Chorionic Villus Sampling

• Amniocentesis

Download a pamphlet on prenatal diagnosis for detailed information.

Who should think about prenatal diagnosis?

• Any woman who is pregnant, especially those who will be 34 years of age or more when their baby is born
• Women and men who have had a child with a chromosome abnormality, birth defect, or other genetic condition
• Women and men who are carriers of a known chromosome rearrangement
• Women and men with a family history of a genetic condition or birth defect
• Women who have had a positive screening test during their current pregnancy
• Women who are at increased risk due to ultrasound findings
• Women who have been exposed to medication, drugs or other dangerous substances during their current pregnancy
• Women and men interested in carrier screening based on their ethnic background

If you have questions about whether you should consider prenatal screening or diagnosis, speak with your provider or contact one of our genetic counselors.

Prenatal Diagnosis at OHSU

Prenatal screening and diagnosis is offered at the OHSU Perinatal Center.

Please feel free to call our office at 503 418-4200 to schedule an appointment for screening or diagnosis or to schedule a consultation with one of our genetic counselors.

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