If Duchenne muscular dystrophy (DMD) runs in your family, you may want to know if your unborn baby has the gene that causes it. This information can help you make decisions about pregnancy and prepare for the medical treatments your baby will need after birth.

There are several prenatal tests your doctor may recommend during pregnancy. Here’s what you need to know about the noninvasive prenatal test (NIPT) and what it can tell you about Duchenne muscular dystrophy before your baby is born.

What Is NIPT?

NIPT is a blood test for pregnant people who want to know the likelihood of their baby having certain genetic conditions.

The test looks at small pieces of DNA in the pregnant person’s bloodstream that are not attached to cells. These DNA fragments come from both the parent and their placenta. Since the DNA from the placenta is usually identical to the DNA of the baby, the test can provide information about the fetal DNA.

NIPT is noninvasive because it doesn’t involve any contact with the unborn baby. Instead, it only requires a blood sample from the pregnant person. For the most accurate results, the test is done after the tenth week of pregnancy. This allows enough time for the placenta’s DNA to enter the parent’s bloodstream.

What Disorders Can Be Detected With NIPT?

Noninvasive prenatal screening can detect many genetic disorders. Most of these happen when there is an extra copy or a missing copy of a gene. The most common conditions NIPT screens for include:

• Trisomy 13 (Patau syndrome)
• Trisomy 18 (Edward Syndrome )
• Trisomy 21 (Down syndrome)
• Extra or missing sex chromosomes (X or Y), such as Turner syndrome, Klinefelter syndrome, XYY syndrome, and triple X syndrome
• Other conditions related to the X and Y chromosomes

NIPT can also detect some disorders caused by chromosomal abnormalities, like missing chromosomes or duplicated parts of a chromosome. NIPT is a newer technology used to screen for genetic conditions. Its capabilities are still growing. In the future, it may be able to detect even more genetic disorders.

What Do NIPT Results Mean?

NIPT is a screening test, not a diagnostic test. It doesn’t give a definitive answer about whether your baby has a genetic condition. Instead, it will tell you if there is a higher or lower chance that your baby will have an abnormality when they're born.

The test isn’t always right. For example, NIPT results might say your baby has a high chance of having a genetic condition they don’t have, or a low chance of one they do have. Sometimes, it can mix up the parent’s DNA with the baby’s.

NIPT has different levels of accuracy for different conditions. NIPT is pretty accurate for detecting Duchenne muscular dystrophy — between 86 percent and 100 percent. But if NIPT results say there’s a high chance of DMD, you’ll still need more tests for DMD after birth or more invasive testing during the pregnancy to know for sure.

Who Should Get NIPT for Duchenne Muscular Dystrophy?

Anyone can ask for NIPT to check for Duchenne muscular dystrophy. Many health insurance plans pay for it, but testing can be expensive if you don’t have insurance or if your insurance won’t cover it.

The genetic change that causes DMD is caused by a problem on the X chromosome. Since females generally have two X chromosomes (and males have one), DMD is almost always passed on by someone who was born female.

If you’re pregnant and have family members with DMD or a family history of it, or you know that you’re a carrier for the condition, it might be a good idea to get genetic testing for your baby. Whether you get NIPT or any other testing done is always your choice. However, if you think there’s a chance your baby has DMD, it’s important to test them soon after birth so you can begin treatments early.

What To Do With NIPT Results

Waiting for and receiving NIPT results can be stressful. It’s OK to feel sad, angry, or upset if the test results aren’t what you hoped for.

No matter what your test results say, it’s a good idea to talk about them with a medical expert. Your doctor or a genetic counselor (an expert in genetics) can tell you more about what your results mean and what your options are.

If the test shows a high chance of your baby having DMD, your medical provider can help you decide what to do next. You might choose to do more testing during pregnancy to confirm the diagnosis or wait and test your baby after they’re born.

Your healthcare provider will help you make the choice that is best for you, taking into account your needs, insurance plan, and desires.

How Do They Test for Muscular Dystrophy in Pregnancy?

If NIPT shows a high chance of DMD, you can choose to do more detailed prenatal diagnostic tests. These tests are more invasive because they involve testing the placenta or amniotic fluid.

One option is chorionic villus sampling (CVS). In CVS, a small sample of tissue is taken from the placenta and tested for DMD genes. This is usually done after 11 weeks of pregnancy. There are a few different ways to carry out this procedure. Your obstetrician will choose the best one for you.

The other way to diagnose DMD is through a procedure called amniocentesis. If you and your healthcare provider decide to do this, they’ll put a needle into your stomach to get a sample of amniotic fluid. The baby sheds cells into this fluid, which can be tested for genetic problems. An amniocentesis can only be done after 15 or 16 weeks of pregnancy.

In both tests (CVS and amniocentesis), the cells taken are checked for genetic problems like DMD. Both CVS and amniocentesis are about 99 percent accurate, but they do have a small risk of miscarriage. Because of this, it’s important to discuss the health risks with your healthcare provider before making a decision.

Find Your Team

On myMDteam, the site for people with muscular dystrophy and their loved ones, members come together to gain a new understanding of MD and share their stories with others who understand life with MD.

Are you thinking about getting a NIPT for Duchenne muscular dystrophy? Or have you already had a NIPT that showed a chance of Duchenne muscular dystrophy? Share your experiences in the comments below or by posting to your Activities page.