Its nothing that mom or dad did we still dont fully understand why it happens.
The extra copy of chromosome 21 can come from the mother or the father.
The only real risk factor for Down syndrome is a mothers age at conception.
As a woman gets older, her chance of having a baby born with Down syndrome increases.
A 20-year-old womans odds for having a baby with Down syndrome are 1 in 2,000.
By age 35, the risk rises to 1 in 350.
At 40, the risk is 1 in 100, and by age 45, its 1 in 30.
Learn More About What Causes Down Syndrome
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How Is Down Syndrome Diagnosed?
The screenings involve blood tests and an ultrasound.
But a screening test is not a diagnosis.
Further checks can verify or rule out a diagnosis.
The features that the baby would have are usually pretty evident to the doctor.
Some babies without the syndrome have Down-like features at birth.
All of these things happen within the general population, she says.
