Down syndrome

Receiving a diagnosis of Down syndrome can be a stressful time for your family. You are being given a lot of new information and you probably have a long list of questions. All of the members of our team in the Down Syndrome Program  at Children’s Hospital Boston are here to help.

We’ll watch your child’s symptoms closely and consider different medications if needed. We make every effort to keep symptoms in check so that your child can avoid unnecessary hospitalizations. At the same time, we choose treatment plans carefully to minimize side effects.

How is Down syndrome diagnosed?

Down syndrome can be detected during pregnancy through various prenatal tests. Down syndrome can also be diagnosed after birth with a chromosomal analysis called a karyotype.

Why are prenatal tests used?

Prenatal tests are optional tests that can be performed during pregnancy to identify a fetus’s sex, age, size and placement in the uterus. Prenatal tests also detect chromosomal conditions, congenital heart defects, and other genetic conditions.

How early should parents consider prenatal testing?

Ideally, the best time to start thinking about prenatal tests is before conception. Although no testing can be done at that point, the doctor can look at your family’s medical history to see if you might have an increased risk for genetic conditions such as Down syndrome. 

The American College of Obstetrics and Gynecologists now recommends that all women be offered prenatal testing.

What are the different types of prenatal tests?

Before any parent decides whether or not to get prenatal testing, it’s important to know all the options and the advantages and disadvantages of each one.  The two types of prenatal tests used to detect Down syndrome are called screening tests and diagnostic tests.

Screening tests

• Screening tests determine what the chances are that your baby will be born with Down syndrome or other medical conditions. This kind of testing does not definitively diagnose a fetus with one of these conditions.

The different types of screening tests include:

• blood tests, which are used to measure protein and hormone levelsin pregnant women. Abnormally increased or decreased levels can indicate a genetic condition.  New blood tests can also detect chromosomal material from the fetus that is circulating in the mother’s blood.

• ultrasound, which is a non-invasive imagining technique that uses sound waves to generate an image of the fetus.  An ultrasound can identify congenital heart conditions and other structural changes that may indicate a diagnosis of Down syndrome.

The combined results of these two tests are used to estimate the chance that your baby will be born with Down syndrome.

Diagnostic tests

• Diagnostic tests can determine whether or not your fetus has Down syndrome with nearly 100 percent accuracy. However, because these tests are performed inside the uterus, they carry a small increased risk of miscarriage and other complications.

The different types of diagnostic testing include:

• Chorionic villus sampling (CVS), a prenatal diagnosis method in which a small biopsy of the placenta is taken for specific genetic testing. CVS is used to detect any condition that involves specific chromosomal abnormalities, like Down syndrome. This test is usually performed during the first trimester between 10-14 weeks of gestation.

• amniocentesis, a prenatal diagnosis method in which a needle is inserted into the amniotic sac that surrounds the baby. Amniocentesis is most often used to detect Down syndrome and other chromosomal abnormalities. This test is usually done in the second trimester, after 15 weeks of gestation.

Testing after birth

Down syndrome can also be diagnosed after the baby is born:

• Since Down syndrome involves a set of unique characteristics, a doctor can usually tell whether a baby should be tested based on a physical examination.

• To confirm the findings, a karyotype (a small blood or tissue sample) can be analyzed to determine the presence of extra material from chromosome 21. This information is important in determining the chance of a mother having a baby with the condition in the future.

What should I do after my child is diagnosed with Down syndrome?

Parents who receive a prenatal diagnosis are given an opportunity to meet and talk with a developmental pediatrician and/or clinical geneticist about Down syndrome to ask questions. Our  Down Syndrome Program works closely with the Advanced Fetal Care Center at Children's.   Please feel free to contact the Down Syndrome Program Coordinator who can provide materials on Down syndrome, make connections, and describe support services.

You can also call our Down Syndrome Program at (857) 218-4329, and we will arrange a time to meet with you and your child.