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What parents-to-be should know about prenatal screening tests

By BPT March 19, 2016

If you're pregnant or hoping to become pregnant, recent headlines may have raised your awareness of birth defect risks. Contagious diseases like the Zika virus aren't the only factors that can affect the development of unborn babies. Fortunately, prenatal testing can do a lot to help relieve your fears - by providing information about your baby's overall health and development, including alerting you to potential chromosomal abnormalities.

Here's what you should know about prenatal testing - and what it can tell you about your baby's health before he or she is born.

* Prenatal tests can be non-invasive - such as a blood test or ultrasound - or invasive, such as amniocentesis.

* Non-invasive tests tend to be screening tests, meaning they're intended to identify higher risks of certain conditions, such as chromosomal abnormalities like Down syndrome.

* Invasive tests are usually used to diagnose or confirm a condition, and doctors often request them after a non-invasive screening test has raised a concern. Invasive diagnostic tests include amniocentesis, in which a sample of your amniotic fluid will be collected and tested; and chorionic villus sampling, which collects and tests a sample of the placenta. A non-invasive, targeted ultrasound exam can also be used as a diagnostic test.

Prenatal tests aim to provide doctors and parents with information about the mother's health and the health of her baby, including the risk of the baby's blood type being incompatible with the mother, the risk of gestational diabetes for the mother, and possible chromosomal abnormalities in the fetus. Depending on your risk factors - such as your age, an existing medical condition, or a history of chromosomal abnormalities in your family - your doctor may recommend one or more types of prenatal testing.

Today, non-invasive screening tests such as an ultrasound and a blood test can provide parents with a wealth of information. For example, the Harmony Prenatal Test, a simple non-invasive blood test, can help determine the risk of a trisomy defect. "Trisomy" means instead of a pair of every chromosome, a fetus has three of one or more chromosomes. The affected chromosome determines the type of defect a baby may have. The test detects risks of trisomy 21 (Down syndrome), 18 (Edwards syndrome) and 13 (Patau syndrome), the most common types of trisomy defects, and it can be done for normal pregnancies, as well as ones considered high risk.

A prenatal blood test for trisomies can be done as early as 10 weeks into your pregnancy, and can provide information about the risk of your baby having this kind of chromosomal abnormality. A recent New England Journal of Medicine study found the Harmony test provided more accurate results than traditional first-trimester screening tests. If the blood test indicates a high-risk result, your doctor should recommend you follow up with additional testing.

Lab-developed blood tests like the Harmony test are developed and validated by laboratories to address unmet medical needs when an FDA-approved test is not available. For more information on prenatal tests, visit the National Library of Medicine's website, www.nlm.nih.gov or the March of Dimes website, marchofdimes.org. To learn more about trisomies and the Harmony Prenatal Test, visit www.harmonytestusa.com.