By Elaine Stillerman, LMT
“Screening for Down Syndrome is Recommended for All Pregnant Women”
Every so often, the medical community revisits its guidelines and takes stock of the recommendations it makes to the general public about health issues. A recent report cited a 15% drop in breast cancer rates in the United States and associated this to the decline in hormone replacement therapy once suggested to treat the symptoms of menopause.
Now, as reported in the New York Times (“Screen All Pregnancies for Down Syndrome, Doctors Say”, by Roni Rabin, Jan. 9, 2007), the American College of Obstetricians and Gynecologists is recommending that all pregnant women receive screening for Down syndrome regardless of their age. (When a test is a screen, the results provide information about the risks of having the disease. When the test is diagnostic, a positive result often means the condition exists.) For many years, this suggestion was made only for women over 35 years of age. The shift was prompted by new, less invasive methods to screen for this genetic defect including an ultrasound exam that can evaluate the risk (not the presence) of Down syndrome as early as 11-13 weeks gestation. In addition, while women 35 and older are at greater risk of conceiving a child with Down syndrome, most affected babies are born to younger women because they have more babies.
The nuchal transluceny screen, while not as accurate as more invasive diagnostic genetic tests such as chorionic villi sampling or amniocentesis, measures the fluid in the back of the neck of a fetus, just beneath the skin. Evidently, there is a compelling connection between the thickening of the neck in this area and the risk of Down syndrome. Combined with two first trimester blood tests, 82-87% of Down syndrome can be detected this way.
Down syndrome has been recognized for centuries, but it wasn’t until 1866 that Dr. John Langdon Down, an English doctor, published an accurate description of the disorder. The
name of the syndrome was coined from his writings. In 1959, French physician Dr. Jerome Lejeune identified Down as a chromosomal defect when he noticed 47 instead of the usual 46 chromosomes present in each cell of people with Downs syndrome. As science progressed, it was finally determined that an extra partial or complete 21st chromosome results in the characteristics of Down syndrome.
Down syndrome occurs 1 in 733-800 births. There are more than 350,000 people in the United States with this disorder. Down does not discriminate and affects people of all races and socioeconomic levels. Individuals with Down syndrome have distinct facial characteristics, moderate to severe cognitive impairment and are at high risk for congenital heart defects and other health problems. Many are considered to be high functioning and can hold jobs and live somewhat independent lives in group homes.
As women delay childbearing, the risks of conceiving a child with Down syndrome increase. According to the American Society for Reproductive Medicine, genetic defects increase as women get older.
The March of Dimes applauds this new guideline and believes it can provide women with better information about their pregnancies.
While Down syndrome is the most common genetic cause of mental impairment and other physical complications, a simple blood test even before becoming pregnant can tell men and women if they are carriers of the leading cause of inherited mental impairment, pervasive developmental delays, seizure disorders and anxiety disorders. Being a carrier of Fragile X occurs 1 in 259 women and 1 in 800 men throughout the world. Because it is a defect of the X chromosome, all men will pass the defect on to all of his daughters. A woman has a 50% chance of passing it on to each of her children. 1 in 4000 boys is affected and 1 in 6000 girls is affected.
Fragile X is a chromosomal defect present at birth. It stays dormant from one generation to the next until a child is born with the full mutation. Unless you have another family member (on either side) with cognitive impairment, you would never think to get tested for the syndrome. But a simple blood test can determine if you are a carrier, and if you are, diagnostic genetic testing can determine if your fetus is affected.
The better informed you are before you become pregnant or while you are pregnant, the easier it will be for you to make decisions about your pregnancy. For more information:
National Down Syndrome Society
www.nas.com
Fragile X
www.NFXF.com | 
