Non-Invasive Fetal Test Detects Down Syndrome

Fetus blood test can identify Down syndrome

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Many pregnant mothers are concerned about fetal tests to detect serious conditions in the baby. They fear that such tests could endanger the baby’s health.

One new study shows that a non-invasive test can accurately predict chromosomal abnormalities in an unborn baby.

Doctors from Tufts Medical Center in Boston, Mass., and other medical centers nationwide studied 2,882 women undergoing prenatal procedures at 60 different locations in the U.S.A.

The blood test that uses DNA sequencing was able to accurately identify all 89 cases of Down syndrome in the fetuses. The test was also able to predict three most common most common conditions involving an abnormal number of chromosomes in a fetus (called aneuploidies) with an accuracy of 100%. 

"Pregnant moms should learn more about fetal screening."

The team’s test included a massively parallel sequencing of maternal plasma DNA in combination with an algorithm. The test was able to detect three prevalent aneuploidies: Down syndrome, Edwards syndrome and Patau syndrome. The study was also able to detect Turner syndrome.

This is the first prospective, multicenter, blinded clinical study to detect all fetal aneuploidies in fetuses, says study author Dr. Diana W. Bianchi of the Mother Infant Research Institute at Tufts Medical Center in a statement.

It shows that massively parallel sequencing of maternal plasma DNA with optimized normalization works, she says.

The study authors, which include doctors from David Geffen School of Medicine at UCLA and Eastern Virginia Medical School, believe that this prenatal test means that fewer invasive procedures can be used to diagnose an abnormal number of chromosomes in the fetus.

A number of screening tests are currently used to detect for chromosomal disorders in an unborn baby. A doctor may use ultrasound or blood tests.

If the mother is considered at high risk for having a baby with Down syndrome a doctor may recommend amniocentesis, in which a sample of amniotic fluid surrounding the baby is withdrawn through a needle, or other invasive procedures.

Most people are familiar with Down syndrome, a condition in which a person has an extra copy of chromosome 21, causing developmental delays and mental retardation. The number of babies born with the condition is rising, occurring in 1 of every 691 babies born in the U.S., according to the Centers for Disease Control and Prevention.

Edwards syndrome is a relatively common syndrome caused by an extra copy of chromosome 18, and is three times more likely to occur in girls than boys, according to the National Institutes of Health. Half of babies born with this condition don’t survive past the first week of life.

Babies born with an extra copy of chromosome 13 have Patau syndrome, the least common of the three aneuploidies. This condition causes severe neurological and heart defects that make it difficult for an infant to survive.

Turner syndrome is when a female is born with a missing or incomplete sex chromosome. It can cause many developmental problems, including short stature, infertility and heart defects.

This study was presented at the annual meeting of the Society for Maternal-Fetal Medicine in Dallas, Texas.

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Last Updated:
February 14, 2012