New Blood Test Is Better at Finding Birth Defects

It's the news that no pregnant woman wants to hear: "There is a chance that something is wrong with your baby." And for most women who undergo prenatal screening, it's a false alarm — followed by days or weeks of anxiety and invasive tests, only to determine the baby is healthy.

But a newly developed blood test for pregnant women could greatly reduce those false alarms, according to research published Wednesday — and it can be done as early as the 10th week of pregnancy. While these blood tests have already been on the market for a while, this is the first study showing how effective they are compared to the older testing methods for all women, not just those considered at high risk of having babies with chromosomal abnormalities.

The test is called the "cell free DNA test" (cfDNA) and it looks at small amounts of actual fetal DNA in mom's blood. Researchers performed the test on nearly 2,000 pregnant women and found that the rate of false positives with this new test was 10 times lower than with standard screening measures, which are done later in the pregnancy.

"If you were screened positive with cfDNA test, there was a 45 percent chance that your fetus had Down syndrome, and if you had a standard test only a 4 percent chance that the fetus had Down syndrome," explained study author Dr. Diani Bianchi, Executive Director of the Mother Infant Research Institute at Tufts Medical Center.

In other words, 96 percent of women with a positive test on the standard screen don't end up having a child with Down syndrome. In order to be truly sure of a diagnosis, women with a positive test undergo more invasive testing such as amniocentesis or chorionic villus sampling. Not only are these tests more invasive, they carry with them a risk of miscarriage.

Jennifer Fontaine has seen the power of the new blood test first hand. After a standard prenatal test, the 29-year-old from Groveland, Mass., got a call at the lab where she works saying there was a chance that her baby had Edwards syndrome (trisomy 18).

"It was devastating. There was a possibility that she wouldn't make it through her first week of life or even the pregnancy."

"I went home immediately and started looking it up online," she said. "It was devastating. There was a possibility that she wouldn't make it through her first week of life or even the pregnancy."

For two agonizing weeks she waited. When she met with the doctors again, they offered her a choice: She could get an amniocentesis, which carries a risk of miscarriage but would give her a definitive answer, or she could repeat the screening with this newly developed blood test.

She opted for the newer screening test and got great news -- her baby tested negative for trisomy 18. "We were ecstatic," says Jennifer, whose daughter Morgan is now a healthy 3-month-old.

The cfDNA test screens for Edwards syndrome and two of the other most common genetic disorders – Down syndrome and trisomy 13 (Patau syndrome). It can be done as early as the 10th week of pregnancy, with results available in about one week. It's currently recommended for pregnant women at high risk for having babies with Down syndrome and other chromosomal abnormalities.

 

Jennifer Fontaine, 29, used the cell free DNA test to find out her child did not have an abnormality. She and 3-month-old Morgan live in Groveland, Mass.

Although the results of the study are encouraging, the American College of Obstetrics and Gynecology has yet to update recommendations on screening. But physicians are hopeful that this could represent the future of prenatal testing.

"Studies such as this one will inevitably challenge them to consider updating their guidelines," said Dr. Brian Skotko, a pediatrician and Co-Director of Massachusetts General Hospital's Down Syndrome Program.

Not everyone is excited about advances in prenatal testing. Some pro-life advocates as well as families of children born with Down syndrome argue that these tests may spell the end of kids with Down syndrome and related chromosomal abnormalities. In particular, they worry that if parents are given news of a possible abnormality based on a more accurate test early in the pregnancy, that would encourage them to abort an affected fetus if further testing bore out the diagnosis.

"The first step is being able to reliably identify those pregnancies that are at risk for abnormalities. What if anything the patient wants to do with the information is up to them."

"There are those who are going to say that you are increasing abortion as testing becomes easier and more widespread," explains Dr. Arthur Caplan, head of the Division of Medical Ethics at NYU Langone Medical Center.

Doctors say that advances like cfDNA simply provide more accurate information. "The first step is being able to reliably identify those pregnancies that are at risk for abnormalities," says Dr. Michael Greene, Chief of Obstetrics at Massachusetts General Hospital. "What if anything the patient wants to do with the information is up to them."

The American College of Obstetrics and Gynecology doesn't track the number of women who get more invasive tests like amniocentesis, but Dr. Greene said the new test can "dramatically reduce" the number by reducing false positives.

This advanced testing also comes with a hefty price tag. Four companies offer cell free DNA testing: Verifi, MaterniT21, Harmony, and Panorama, and a single test generally costs anywhere from $795 to $2,000, compared to standard screens that are usually around $200-250. And until further research is done, it remains unlikely that this will be covered by standard insurance plans.

"We think insurers are unlikely to cover it for women not at high risk. But as more and more studies come out with similar results, we think more insurers will cover," explains Dr. Bianchi.

For Jennifer Fontaine, who ended up paying for it out of pocket, it was well worth it. "It was 100 percent worth it. It gave us the peace of mind — even if it did come back positive, we were prepared for what was ahead."