Healthy Habits: Risk for Down Syndrome

Heard Who is at Risk for Having a Child With Down Syndrome?
Down syndrome is the most commonly diagnosed chromosomal disorder in the United States. Babies diagnosed with Down syndrome experience abnormalities in their physical development as well as delays in intellectual development. If you are planning on becoming pregnant, you may be wondering, what are the risk factors associated with having a child with Down syndrome?
Previously Giving Birth to a Child Diagnosed With Down Syndrome
In general, couples who have previously given birth to a child with Down syndrome have a one percent increase in the risk of giving birth to another child with Down syndrome. This difference is small, but it is important to know that it exists. If you have a child with Down syndrome and plan on having more children, work with a genetic counselor to understand your personal risk of having another child with Down syndrome.
Advanced Maternal Age
When pregnant at advanced maternal age of 35 years and older, the chance of giving birth to a child with Down syndrome increases. With advanced maternal age, eggs will have a greater risk of incorrect chromosome division. The likelihood of having children with Down syndrome increases from 1 in 350 at maternal age 35 to 1 in 100, and even further as age increases.
Carrying a Genetic Translocation for Down Syndrome
Down syndrome more often occurs due to abnormal cell division leading to inheritance of three copies of chromosome 21. However, sometimes Down syndrome is caused by the inheritance of a chromosome with an error called a translocation either from the mother or the father. According to the National Down Syndrome Society, the percentage of cases of inherited Down syndrome account for roughly four only percent of all diagnoses.
In a translocation, a piece of one chromosome - in this case, the twenty-first chromosome - detaches and reattaches to a different chromosome. Children who inherit Down syndrome will have 46 chromosomes. However, they will have additional material from the twenty-first chromosome that causes the signs and symptoms of Down syndrome.
Is It Possible to Test My Baby for Down Syndrome During Pregnancy?
For women who are at risk for giving birth to a child with Down syndrome, prenatal genetic screening will be recommended by their obstetricians. Noninvasive prenatal genetic testing can be performed as early as 9 weeks into your pregnancy using nothing more than a blood draw from the mother. The results from this test give your doctor information that allows him or her to analyze the risk that your child may have Down syndrome. If there is a high risk, you will have the option of further testing.
When Should I Discuss My Health Risks With My Doctor?
If you are planning on becoming pregnant, it is best to speak with your doctor before conception. Your doctor will help you understand any necessary health changes to make before conception to help ensure a healthy pregnancy. She or he will also discuss your and your partner’s medical history, in addition to your family medical history, to analyze the risk that your child may be born with a genetic disorder.
Sources:
http://www.ndss.org/Down-Syndrome/What-Is-Down-Syndrome/
http://www.yourgenome.org/facts/what-is-meiosis
http://americanpregnancy.org/birth-defects/down-syndrome/
http://www.marchofdimes.org/complications/down-syndrome.aspx
https://ghr.nlm.nih.gov/condition/down-syndrome