This New Blood Test Is Crucial For Pregnant Women

by Abby Norman

Over the years science has advanced to give expectant parents a lot of information about their baby, often months before they're born. Advances in genetic testing have made it possible to know if a baby will be born with a wide variety of genetic conditions — some of which can be serious. A new blood test can detect genetic diseases as early as 6 weeks into pregnancy — much earlier than other tests commonly offered.

Single-gene genetic disorders, which include muscular dystrophy, Huntington's disease, sickle cell anemia, as well as about 100,000 others, are collectively more common than Down's Syndrome. Testing for these conditions has been fairly limited, the most common screening tool being amniocentesis. While generally regarded as safe, amniocentesis does carry risks, as it involves injecting a needle into the amniotic sac. It also only tests for a limited number of genetic conditions.

A researcher named Rossa Chiu at the Chinese University of Hong Kong has developed a faster, safer, easier, and likely cheaper alternative. One that could be available in as little as five years. Chiu's simple blood test examines DNA from both parents, looking for increased mutations in the mother's single nucleotide polymorphisms (SNPs).

Chiu and her colleagues say that the screening, which only requires a blood sample, can be performed by any laboratory, and is low-risk compared to a procedure like amniocentesis. The results come back faster, too: in about 1-2 weeks, depending on the speed of the lab's processing.

While the test might be easy and relatively risk-free, many groups have argued that the ethics of prenatal testing, which allows parents to make informed decisions about the viability of the pregnancy. Some anti-choice groups have argued that prenatal testing encourages abortions in cases of Down's Syndrome and other genetic conditions. Others argue that giving parents the ability to "screen out" pregnancies has eugenic overtones.

Aside from the fact that these arguments completely discount a woman's right to choose abortion in any circumstance, they also fail to consider that for many genetic conditions, early intervention can make an enormous difference. For some conditions, initial disease-modifying interventions can be started during pregnancy, or soon after birth — but only if the conditions are known about.


One particularly serious condition that Chiu's blood test can uncover, congenital adrenal hyperplasia, can be prevented if steroids are giving before the 9th week of pregnancy. Amniocentesis, which can also be used to detect the condition, is generally not performed until the 15-20th week of pregnancy.

Keeping that in mind, these simple noninvasive measures to test for genetic conditions could potentially lead to earlier detection of conditions that would be otherwise fatal. That fact alone throws a major wrench in the argument that genetic testing is destined to lower birth rates: if anything, there's reason to hope that babies who wouldn't have survived before can have a chance at a life. Perhaps even one that's free from the effects of a genetic condition entirely.