For most women, your Down syndrome risk is based mostly on the mother's age. This calculator will let you know your own personalized risk based on your age.

What is Down syndrome?

Down syndrome is a genetic disorder caused by a duplication chromosome. Patients with Down syndrome have two copies of chromosome 21 so they are born with 47 chromosomes as opposed to the normal 46. Another name for the condition is Trisomy 21. 

Down syndrome is named after John Langdon Down, the British doctor who first described it in 1866. The extra genetic material causes delays in the way a child develops. In general, symptoms of Down syndrome can vary widely from child to child. While some kids with Down syndrome need a lot of medical attention, others lead very healthy and independent lives.

Who is at risk for Down syndrome?

Advanced maternal age is a risk factor for Down syndrome. Maternal age over of 35 at the time of pregnancy increases the risk of having a child with Down syndrome to one in 400. That risk jumps to one in 35 for women over 45.  

Despite the increased risk to women over 35, women under the age of 35 give birth to more children with Down syndrome than older women. Statistically, the increased number of Down syndrome cases is associated with the number of overall births to women under 35 — more births equates to more children born with the syndrome. Women who have given birth to a child with Down syndrome are at increased risk of having a second or subsequent child with the condition. 

What are the symptoms of Down syndrome?

The duplicate chromosome 21 causes physical and mental abnormalities of varying severity. Physical abnormalities may affect the head, eyes, neck, and fingers.

Children with Down syndrome tend to have flat facial features, upward slanted eyes, a short neck and fingers, and a smaller than average head size. Patients may also develop poor muscle tone. 

Physical and mental development may be slower than peers or stunted. Mental and social delays are typically present – though in varying degrees. Delays may manifest as:

  • Slower learning
  • Agitation
  • Shortened attention span

How is Down syndrome diagnosed?

Physical abnormalities may affect the physical development of internal organs, including the brain, eyes, heart and other organs. Down syndrome may increase the likelihood of:

  • Heart-related birth defects
  • Dementia
  • Vision problems
  • Gastrointestinal blockage
  • Joint problems
  • Chronic constipation
  • Hypothyroidism

What is the treatment for Down syndrome?

There is no treatment or cure for Down syndrome. Patient health issues are treated on a case-by-case basis. Patients with some organ deformities, including heart defects or gastrointestinal blockage may require surgery. 

How does Down syndrome affect pregnancy?

Down syndrome in females does not typically affect the ability to get pregnant, stay pregnant or give birth to a normal, healthy baby. 

What is the life expectancy of someone with Down syndrome?

Patients with Down syndrome can live long, productive lives with proper medical care, special education, and life training. Medical attention may be required for life due to the potential for physical abnormalities and conditions.

Risk table from: From Hook EB. JAMA 249: 2034-2038, 1983

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Pregnancy Guide for Women 35 and Over
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