What is the chance that my baby has Down syndrome? If you are asking the question, you are probably pregnant or considering becoming pregnant.
Most people have seen a child with Down syndrome; it is quite easy to recognize. What people fear is not so much the physical problems these children present, but the mental retardation caused by the extra chromosome 21.
The incidence of Down syndrome increases with the age of the mother. Although alcohol and tobacco use have been linked to other conditions, they are not believed to increase the risk of Down syndrome. According to the Merck Manual, a time-honored medical reference, the overall risk is 1 in 800. However, for babies born to mothers in their 20s, the risk is only 1 in 2,000 births. At age 35, the risk increases to 1/365 and at age 40 it is approximately 1%.
However, the answer is a bit more complicated because not all Down syndrome has the same genetic cause. Most cases (about 95%) are due to a second copy of a complete chromosome 21. The other 5% of cases are due to an extra piece of chromosome 21 getting stuck on a different chromosome (called a translocation).
The genetic cause can be determined by examining the child’s and / or parents’ chromosomes. If the mother has a translocation, the risk of having a child with Down syndrome is about 1 in 10. If the father is a carrier of the abnormal chromosome, the risk is about 1 in 20. Chromosome testing is not usually done. they would perform the parents unless they ‘I’ve already had a child with Down syndrome.
Pregnant women can be tested to see if their baby is likely to have Down syndrome, but their insurance may or may not cover this test. Because the test is expensive (hundreds of dollars), not entirely accurate, and potentially dangerous to the fetus, you should discuss the reasons for testing and the reasons for not testing with your doctor.
While it is true that children with Down syndrome suffer from a variety of problems, many are gifted with a great capacity for love. Don’t let fear blind you to learning more about love than you can imagine.
Copyright 2010 Cynthia J. Koelker MD
