Down Syndrome is a chromosomal disorder that can cause intellectual disabilities, distinctive physical features, and other health problems. This includes hearing impairment, heart defects, thyroid disease, etc.

Most couples planning to become pregnant would be eager to learn more about Down syndrome. They have two foremost questions – How to identify down syndrome during pregnancy or How to identify a down syndrome baby.

We have detailed the information on two major invasive procedures that can identify Down Syndrome in unborn babies.

What does an invasive procedure mean?

As the name suggests, it is a medical procedure that requires an incision in the body. This is done by puncturing the skin or inserting clinical equipment into the body

Down Syndrome diagnosis requires an invasive procedure with some screening and diagnostic tests. This helps to diagnose babies with Down syndrome.

NOTE: Despite their invasive nature, these procedures pose little risk to a baby and a parent.

When do you need invasive down syndrome tests?

The fetal expert may suggest you for one of these tests under the following circumstances;

  • If you are over 35 years of age, and if you are at a higher risk of having a baby with a genetic disorder
  • If your family’s history has a congenital disability or any relevant genetic disorder
  • If your partner carries a genetic disorder
  • If you’ve had previous pregnancies with genetic disorders
  • If you have incompatibility in your Rh levels (which could probably attack the red blood cells of your baby)

What are the types of invasive procedures that can identify Down Syndrome?

The general procedure requires. two kinds of invasive diagnostic tests done during pregnancy that help in down syndrome identification. They include:

1. Chorionic Villus Sampling (CVS)

2. Amniocentesis

1. Chorionic villus sampling (CVS):

In a prenatal test, the CVS is taken using a sample from the placenta, and the test is done when you are in the 10th to 13th week of  your pregnancy.

A sample cell, called the “chorionic villi” found around the placenta is taken to trace the exact trait of the gene.

CVS is done earlier to the Amniocentesis test, and the results are procured within 10 days.

The benefit of this test is that it allows a woman to make choices at the early stage of pregnancy. If the baby is diagnosed with a chromosomal disorder,  she might face the distressing situation of terminating her pregnancy.

Do remember, if you wish to get the amniocentesis test for reconfirmation, you have to wait for an additional two weeks. And this waiting has its own risks.

What is the CVS test procedure?

Before going in for this test, the fetal expert sonographer may counsel you regarding the benefits and risks of the procedure. An initial ultrasound is taken to confirm the gestational age and the location of the placenta. This is a crucial procedure as the CVS can be conducted only during the 10-12 weeks of your pregnancy.

CVS is performed in different two ways;

Vaginal: A speculum is inserted into the vagina  to collect the cells. This is followed by inserting a very thin plastic tube into the cervix. The fetal medical expert removes the sample from the placenta with the help of the ultrasound images.

Abdominal: The sample is collected by inserting a thin needle through the abdomen into the placenta. This is similar to the amniocentesis procedure.

Once the chorionic villi sample is obtained, it is then sent to the lab, where the cells are allowed to grow a fraction more with the help of a special fluid. This is tested again after a week. The results will ideally take two weeks of time.

There are good chances of diagnosing the abnormalities in an unborn’s fingers or toes during the 9th week. However, a test taken in the tenth week of pregnancy is more reliable.

CVS is highly accurate. If there are any abnormalities in the test, you can meet the fetal genetic counselor to discuss other options.

2. Amniocentesis

The Amniocentesis test is done by taking a sample of the amniotic fluid, a pale and yellow-colored fluid that surrounds your baby. This particular fluid is picked as it contains critical information to diagnose if your unborn baby has any chromosomal disorders. Ideally, this test is done anytime between the 15th and 20th weeks of pregnancy. 

Apart from the Chromosomal Disorder associated with Down Syndrome, the test also helps to diagnose genetic disorders including cystic fibrosis, Tay-Sachs disease, and neural tube defect (a defect that affects the baby’s brain and/or spine).

What is the Amniocentesis Procedure?

Your fetal specialist might do an ultrasound scan of your abdomen during the procedure. With the ultrasound sound waves, she would examine the position of your uterus, placenta, and the gestational period of the unborn baby.

With the guidance ofthis ultrasound wave, she would insert a very thin needle into your abdomen to extract a small amount of the amniotic fluid.

Post extraction, she would again perform an ultrasound to check the baby’s heartbeat. The average time taken for this test is about 15 minutes.

Concluding Thoughts

The American College of Obstetricians and Gynecologists recommends pregnant women of all ages to undergo screening and diagnostic tests to identify Down syndrome.This is because, on average,  1 in 800 babies are affected by down syndrome.

However, the decision to have invasive genetic testing is totally up to the couple as it carries a 1% risk of miscarriage. If your unborn is diagnosed with Down Syndrome, please discuss the same with a fetal expert or a genetic counselor for clarity and advice.

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