Dr. MJ Bazos MD,
Patient Handout
Down Syndrome: What
You Need to Know When You're Pregnant
What is Down syndrome?
Down syndrome is one of the most common genetic
disorders. It's caused by the presence of an extra copy of chromosome number 21.
This condition is called trisomy 21.
What problems do babies with Down
syndrome have?
Down syndrome usually causes mild to moderate
mental retardation, or slow mental growth. Almost half of babies with Down
syndrome are born with heart problems. Some of these problems can only be fixed
with surgery. Some babies with Down syndrome have intestinal problems, vision
trouble or hearing loss. Many of these problems can be treated.
Are some people more likely than
others to have a baby with Down syndrome?
If you have already had a baby with Down
syndrome, you are more likely to have another one. If you have been diagnosed
with a chromosome abnormality, you have an increased risk of having a baby with
Down syndrome.
The risk of Down syndrome increases with the age
of the mother, as shown in this table:
Risk of Down Syndrome
|
Mother's age
|
Chance of having a baby with Down
syndrome
|
|
20 years
|
1 in 1,600
|
|
25 years
|
1 in 1,300
|
|
30 years
|
1 in 1,000
|
|
35 years
|
1 in 365
|
|
40 years
|
1 in 90
|
|
45 years
|
1 in 30
|
|
|
Can Down syndrome be diagnosed
during my pregnancy?
Amniocentesis and chorionic villus sampling are
two tests that can be used to look for Down syndrome during the first half of
your pregnancy. However, these tests can sometimes cause a miscarriage.
Therefore, these tests are used only when there is a high chance of a genetic
problem in the baby.
Is there another way to tell if my
baby might have Down syndrome?
A blood test called the "triple screen" can be
done between the 15th and the 18th weeks of pregnancy. The triple screen cannot
tell for sure if your baby has Down syndrome, but it can tell if the risk is
higher. If the test is positive, it means your risk of having a baby with Down
syndrome is higher. But remember that most women with a positive triple screen
have babies without Down syndrome.
A negative triple screen means that the chance
of Down syndrome is low. However, it doesn't guarantee that a
baby doesn't have Down syndrome.
Should I be tested?
This decision is up to you. Talk with your
doctor about your risk of having a baby with Down syndrome. Think about whether
you really want to know if your baby has Down syndrome. The box below lists
groups that can give you more information on Down syndrome.
Websites:
