Aug 15, 2000 Table of Contents

Please note: This information was current at the time of publication. But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit familydoctor.org, the AAFP patient education Web site.

Information from Your Family Doctor

Down Syndrome: What You Need to Know When You're Pregnant

Am Fam Physician. 2000 Aug 15;62(4):837-838.

See related article on Down syndrome.

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

Risk of Down Syndrome

View 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 a baby without Down syndrome.

Sources for Information About Down Syndrome

You can call or write to the following organizations for more information:

March of Dimes Birth Defects Foundation

1275 Mamaroneck Ave.

White Plains, NY 10605

1-888-MODIMES (663-4637)

Web address: http://www.modimes.org

National Institute of Child Health and Human Development

NICHD Clearinghouse

PO Box 3006 Rockville, MD 20847

1-800-370-2943

Web address: http://www.nichd.nih.gov

Ask for the brochure, “Facts about Down Syndrome” (available in English and Spanish).

National Down Syndrome Society

666 Broadway St.

New York, NY 10012

1-800-221-4602; 212-460-9330

Web address: http://www.ndss.org

National Down Syndrome Congress

7000 Peachtree-Dunwoody Rd. NE, Bldg. 5, Suite 100

Atlanta, GA 30328-1662

1-800-232-6372; 770-604-9500

Web address: http://www.ndsccenter.org


This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at http://familydoctor.org.

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.

Copyright © 2000 by the American Academy of Family Physicians.
This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Contact afpserv@aafp.org for copyright questions and/or permission requests.

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