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Prenatal Screening for Down Syndrome

Prenatal testing can help determine if your baby will have certain conditions or birth defects like Down Syndrome. Learn the details here.

Published by Anja Health on

August 21, 2022

— Updated on

September 8, 2022

Expecting or planning families want the best for their baby, especially when the baby's health is concerned. One health condition widely thought about during pregnancy is Down syndrome. Specific prenatal genetic testing is available for the early detection of Down syndrome.

However, many people are unaware of the process, what can be done, and what things mean for Down syndrome and prenatal genetic testing. Before your baby is born, it is important to understand the ins and outs of Down syndrome prenatal genetic screening and testing.

A brief overview

Down syndrome is a genetic disorder where a person has an extra chromosome. Chromosomes contain genes, and people are typically born with 46 chromosomes. Individuals with Down syndrome are born with an extra copy of chromosome 21. This condition is called 'trisomy,' which makes up about 95% of individuals with Down syndrome.

In the United States, Down syndrome is the most common chromosomal disease. The three types of Down syndrome are Trisomy 21, Translocation Down syndrome, and Mosaic Down syndrome. Although individuals with down are uniquely different, Down syndrome does pass similar characteristics that include:

  • Small ears
  • Flattened face
  • Small hands and feet
  • Short neck
  • Intellectual and speech delays
  • Shorter height
  • A tongue that sticks out of the mouth
  • Almond-shaped or upward-slanted eyes

What does the test involve?

Prenatal screening for Down syndrome is a routine part of prenatal care. It can help identify if someone's baby has Down syndrome while the baby is still in gestation. The prenatal screening starts with a blood test and ultrasound. "Markers" inside of the pregnant person's blood can help identify if there is an increased likelihood of Down Syndrome. The ultrasound searches for the Down syndrome indicator, fluid at the back of the baby's neck. Blood tests in the second-trimester search for three to four different markers.

A diagnostic test is performed to determine if there is a chance of Down syndrome. Genetic materials are extracted to test for the extra chromosome 21. Extraction procedures include:

Chorionic villus sampling (CVS)

Sample cells are taken from the placenta. This test is typically performed between 10 and 13 weeks of pregnancy and carries a very low risk of miscarriage.

Amniocentesis sampling

The sample is from amniotic fluid, taken through a needle inserted into the pregnant person's uterus. This test is typically performed after 15 weeks of pregnancy and carries a very low risk of marriage.

Percutaneous umbilical blood sampling (PUBS)

A blood sample is from the umbilical cord. While this test is the most accurate, it typically can't be performed until well into your second trimester of pregnancy.

No need to make any special preparations for testing for Down syndrome. Still, we recommend you talk to your health care provider about the pros and cons of testing.

What are the risk factors? 

Unfortunately, there are some risks to prenatal genetic testing (though small). Amniocentesis and chorionic screening and sampling can risk the safety of the pregnancy. The two sample-collecting methods are mildly invasive in that samples are collected from the amniotic fluid and around the baby. This creates a potential risk of miscarriage.

Some testers do report associated emotional and social risks. Hearing undesirable results can cause tensions between family members, placing undeserved blame on carriers and parents feeling insecure about positive results. The female parent's age also plays a risk factor, increasing the chances of having a Down syndrome birth. The odds increase after age 25 and 35 and reach 1 in 100 by age 40.

What do the results mean?

Results from Down syndrome screening tell you if your baby has a higher risk of having Down syndrome, but they can't tell you definitively. Before testing and/or after you get your results, we recommend you speak to a genetic counselor who is trained in genetic testing and can help you understand your results. You may consider getting additional diagnostic testing if your results come back abnormal.

How to find out if you're a carrier

Parents curious about Down syndrome testing do not have to wait until pregnancy. Just as there is prenatal screening, genetic carrier screening is also available. Recessive disorders, like Down syndrome, require individuals to inherit two genes (one from each biological parent). Carriers are people who inherit one of the two genes.

Carrier screenings spot altered genes that are indicators of genetic conditions. Samples from the tester's cheek are taken (blood, saliva, or tissue). Only one biological parent is tested first, and the other parent tests if the first test has a positive result. Although carrier screening is not one-hundred percent accurate, it does give families an awareness to consider prenatal testing.

Treatment options for down syndrome 

There is currently no effective treatment for Down syndrome except physiotherapy and special education.

People with Down syndrome will need various types of care throughout their lives, varying on the individual. Some living assistance may include behavioral therapy, speech or educational assistance, associated wellness visits, reproductive counseling, and more. Recommended treatment options include:

  • Early Intervention
  • Educational Therapy
  • Assistive Devices
  • Prescriptions and Supplements

Part of the difficulty is that even though we know a lot about people with Down syndrome, like their characteristics and their features—even that they will develop Alzheimer's disease—researchers still don't have a good understanding of how brain development in Down syndrome is different.

Researchers need to better understand how the syndrome works to identify new therapies to treat Down syndrome. However, current animal models that study the syndrome don't mimic the disorder well. Researchers at the University of Wisconsin have created a new stem cell model to study how changes to brain development in the womb result in intellectual disability in people with Down syndrome. This model is very promising to better understand how the syndrome works and, hopefully, develop better treatment options for Down syndrome.

Bank your stem cells with Anja Health

Becoming a parent is a big responsibility, and, naturally, you are interested in learning about the possibility of having a child with Down syndrome. Many health professionals will say the journey begins with prenatal screening for Down syndrome. Although important, there is an additional precaution that parents can take.

Stem cells play a prominent role in Down syndrome treatment. You can prepare for the possible need for this treatment by saving important stem cells through cord blood banking. Having the stem cells ready and available as soon as possible gives your child the best chance of early treatment if Down syndrome is present. Anja Health is here to help you get started in this process and secure your family's ability to explore all needed treatment options.

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