PRENATAL SCREENING & DIAGNOSIS
If you have received prenatal test results that confirm or suggest a diagnosis of Down Syndrome, we are here to provide whatever support would be most helpful to you and your family.
There are many different types of prenatal tests for Down syndrome. In order to best understand what the results mean for you and your pregnancy, it is important to understand which type of test you received:
The triple screen, quadruple screen, first trimester combined screen, integrated screen, and contingency screen are all different types of prenatal screening tests that involve, to varying degrees, bloodwork and ultrasound findings. These screening tests provide you a risk assessment, not a diagnosis, and the results should be communicated as such. In other words, you should not be told that your child is positive or negative for Down syndrome. Instead, the results indicate the probability (or degree of chance) that your child will have Down syndrome. For example, you might be told that your child has a 1 in 300 chance of having Down syndrome.
Current Down syndrome prenatal screening results are anywhere from 65 to 95 percent accurate depending on the test.
A non-invasive prenatal screen that measures cell free DNA is now commercially available. It is a blood test that can be performed as early as 10 weeks gestation and allows for quantifying the amount of placental DNA in maternal blood. The results are delivered as a positive/high risk or negative/low risk, but confirmation requires further testing in the form of CVS or amniocentesis. It is important to understand that while these tests are reported to detect >99% of cases of Down syndrome, they are NOT 99% accurate. A positive or high-risk result indicates an increased chance for a expectant mother to have a child with Down syndrome. The actual chance for Down syndrome (PPV: Positive Predictive Value) is dependent on maternal age, timing during the pregnancy, family history and ultrasound findings. A negative or low risk result indicates the pregnancy is unlikely to have Down syndrome. If expectant mothers wish to confirm these results, healthcare providers recommend that expectant mothers proceed with diagnostic testing such as chorionic villus sampling (CVS) or amniocentesis. As always, genetic counseling is recommended to discuss all screening and testing options.
Determining with virtual certainty that your child has Down syndrome requires an invasive test, where a needle is inserted into the pregnant abdomen. Usually administered after the 15th week of pregnancy, an amniocentesis analyzes a uterine fluid sample, which contains fetal cells. The chromosomes of these cells can be tested to determine whether Down syndrome is present. Administered usually 10 to 14 weeks into the pregnancy, chorionic villus sampling or CVS analyzes fetal cells like in an amniocentesis but using placental not uterine fluid. Both these tests carry a small risk of miscarriage.
If you have received prenatal tests that suggest or confirm Down syndrome, remember that the NCDSA is here for you with accurate, up-to-date information and the opportunity to speak with a parent mentor through our Parents First Call Program. See below for details.
PARENTS FIRST CALL PROGRAM
For expectant parents of children with Down syndrome, any opportunity to speak with other parents who have experienced what you are experiencing can be invaluable.
The NCDSA’s, NC Parents First Call Program, is a volunteer, state-wide group of trained parent mentors available 24/7 to listen, share, answer questions, and provide valuable information. If you would like to speak with a First Call parent who also received a prenatal diagnosis, please fill out this form.
Resources included in NCDSA’s prenatal information packet and online:
Understanding a Down Syndrome Diagnosis contains the latest medical and developmental information about people with Down syndrome as well as resources, pregnancy options and helpful visuals and graphics. This booklet has been reviewed by all the major medical organizations involved in expectant mothers health. A copy of this booklet is included in NCDSA’s Prenatal Information Packet or you may download a digital copy here.
Visit our national affiliate, the National Down Syndrome Congress (NDSC), for a wealth of information for expectant parents.
A free, downloadable book for expectant parents who have made the decision to continue their pregnancy, Diagnosis to Delivery: A Pregnant Mother’s Guide to Down Syndrome, is available at www.downsyndromepregnancy.org. Includes strategies for coping with a Down syndrome diagnosis, medical guidelines for the first year, and support resources.
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