New Blood Test Detects Down Syndrome, Less Invasive than Current Methods

A new non-invasive test may determine if an unborn baby has Down syndrome during the first trimester of a pregnancy, found a new study by UK researchers.  

Researchers at the Harris Birthright Centre at King's College in London developed a test which analyzes a baby's DNA which is detectable in the mother's blood to determine chromosomal disorders.

In a study of 1,005 pregnant women, published in the Ultrasound in Obstetrics & Gynecology journal, blood samples were taken at 10 weeks and sent to a laboratory in America where fetal DNA circulating in the mother's blood was analyzed and returned within two weeks.

Currently, pregnant women who want to determine if their unborn child will have any genetic diseases need to endure invasive procedures like an amniocentesis that might put the baby at risk. During the amniocentesis test, a long needle is inserted into the belly to pull fluid from the sac that surrounds the baby. Chorionic villus sampling (CVS) involves testing a small sample of the placenta. Both invasive procedures have a one in 100 risk of miscarriage. 

Experts conducting the ongoing study say the new method could save tens of thousands of women the need for more invasive testing, and prevent almost 300 miscarriages each year that are caused by CVS.

However, this new blood test may offer a non-invasive option for expecting mothers.

According to the National Down Syndrome Society, one in every 691 babies in the United States is born with Down syndrome. 

Down's syndrome is a genetic disorder that causes lifelong intellectual disability, developmental delays and other health problems. It is the most common genetic cause of learning disabilities in children, according to the Mayo Clinic.

The disorder is caused by a third copy (trisomy) of 21st chromosome in 90 percent of cases. People are supposed to have two copies of 23 chromosomes, thread-like structures that are made up of DNA. Most of the time it's not inherited, but caused by a mistake in cell division during development.