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Prenatal Screening for Down Syndrome Risk

Knowing as much as you can before your baby is born can help you make health care decisions. Here’s what to expect from a Down syndrome screening.

Down syndrome is the most common genetic condition in the United States. It’s a chromosomal abnormality also known as trisomy 21, where an extra copy of chromosome 21 appears as a result of an error during cell division and replication. While babies with extra chromosomes sometimes miscarry, certain abnormalities, like Down syndrome, can survive.

While babies with Down syndrome can have normal, high-quality lives, there are health conditions associated with the condition that might require extra care or interventions. This is why, for some high-risk mothers, taking a screening test to learn your baby’s risk for Down syndrome could be worth considering. When should you take the test, what does it entail, and what do the results mean?

When to Consider Screening

Any woman can have a baby with Down syndrome. While there are no known behavioral or environmental causes for the disorder and it’s usually not hereditary, there are some factors that can increase a baby’s risk of being born with the condition. The risk factors are worth talking with a genetic counselor about to determine the possible risk for your child.

• Having one child or family member with Down syndrome
• An advanced maternal age of 35 years or older
• A parent who’s a known carrier of genetic translocation

In addition, screening tests don’t pose a risk to you or your baby because they’re noninvasive. You can get information about your baby’s risk of having problems without worrying about a chance of miscarriage. A Down syndrome screening test result gives you the opportunity to begin planning, whether that means addressing lifestyle changes, identifying resources for your family, or discussing further testing with your health care team.

The Screening Tests

While testing is voluntary and should be discussed with your health care provider, all women should be offered options for first and second-trimester screening during their pregnancies. Depending on how far along in your pregnancy you are and what your doctor recommends, there are a few screening tests that you could take.

First-Trimester Screening

This early Down syndrome screening test involves a blood test as well as a special ultrasound scan. The blood test measures levels of certain proteins in the blood that are associated with a higher risk of Down syndrome babies. The ultrasound scan, also called a nuchal translucency test, measures the clear space in the tissue at the back of a baby’s neck, which can also indicate the presence of Down syndrome.

Second-Trimester Screening

The second-trimester screening is also called a multiple marker, triple, or quad screening. It measures the levels of certain substances in the mother’s blood associated with an increased risk of Down syndrome. When combined with the mother’s other risk factors and the results of other tests, this can be used to determine a baby’s Down syndrome risk.

Integrated Screening

Integrated screening tests combine first- and second-trimester screening results to measure your risk. This screening process looks at the results of the first-trimester blood test and ultrasound as well as the second-trimester blood test. Once all of the tests are completed, the risk is determined.

Sequential Screening

This screening test takes a look at the results of the first-trimester ultrasound and blood test. If the results indicate an increased risk, the mother is offered diagnostic testing. If the results are low risk, the mother is offered a second-trimester blood screening and, ultimately, an adjusted risk assessment with all of the results in mind.

Interpreting the Down Syndrome Screening Test Results

The screening test results can’t tell you whether your child actually has Down syndrome. No matter which test you take, the results will come in the form of a ratio that expresses your baby’s chances of being born with the condition. Based on the results of the screening test as well as your age, you’ll be placed into higher or lower risk groups. Being high-risk doesn’t mean that your child has the condition, nor does being low risk mean that there aren’t any problems: screening tests are designed to look for a few conditions, but not every genetic problem or birth defect. This is why talking to a genetic counselor is an important part of a Down syndrome screening process.

What if I’m High Risk?

Being in a high-risk group doesn’t mean that your baby has Down syndrome. The only thing that can identify the disorder is a diagnostic test. If the results of a screening test are a cause for concern, you can talk to your health care team about the risks and benefits of having a diagnostic test performed. Diagnostic tests like amniocentesis and chorionic villus sampling can confirm a diagnosis, but can be invasive.

Valley Perinatal Services Prenatal Screening

Pregnancy is filled with a lot of emotions, and for many mothers, anxiety is among them. If you’re a high-risk expectant mother, there might be more anxiety than in a pregnancy with normal risks. Knowledge is important not only for alleviating your fears but also for being able to plan for complications and future health care.


Valley Perinatal Services is here to help high-risk mothers and children in Phoenix, Tucson and Sierra Vista to achieve the best possible outcome from pregnancy. Our staff of experienced perinatal specialists are trained in cutting-edge technology that can give you some peace of mind during what can be an emotional time. We can perform ultrasound imaging, genetic counseling, and other screening and diagnostic tests to look for Down syndrome and other chromosome abnormalities. Talk with your Ob/Gyn about co-managing your pregnancy with Valley. Call 480.756.6000 or or contact us online.

Gynecological Screening With Valley Perinatal Services

Medicine is making advances every day, so reliable early screening could be possible in the future. We at Valley Perinatal want to make sure our patients and their families are cared for to the highest standards, and we’ll look for the information you need to inform your future healthcare decisions. Whether you’re looking for genetic testing to examine your risk for ovarian cancer, or want a screening test to examine something a little closer, we have specially trained staff and state-of-the-art equipment to help you find the source of your health concerns, monitor them for any changes, and be with you every step of the way. For more information or to schedule a service, call 480.756.6000, or contact us online.