CVS test (Chorionic Villus Sampling) to find out about your baby's genetic diseases early

If you are a mother who is about to have a baby, your doctor has probably told you about a special test that can tell you a lot about the baby's health in advance. CVS is one such test. The name may sound a little scary, but it is an important test for many mothers. Let's take a look at what it is, why it is done, how it is done, and whether it is something to be afraid of.

What exactly is this CVS test?

Simply put, CVS (Chorionic Villus Sampling) is a special test performed during pregnancy. It is used to check if your unborn baby has any genetic diseases or birth defects. Your doctor will only recommend this test if there is any suspicion that your baby has any genetic disorders or birth defects.

But this is not a mandatory test. This is something that you should decide on completely based on your wishes. Only do this if you feel it is right for you after discussing all the pros, cons, and risks with your doctor.

This test is usually done between 10 and 13 weeks of pregnancy. Another advantage of this test is that it can also accurately determine the gender of the baby (whether it is a girl or a boy).

How to do the test?

What happens in this is that a very small sample of cells is taken from your baby's placenta. We call these cells `(Chorionic Villi)`. Now you might be wondering why a sample is taken from the placenta and not from the baby. Think about it, a baby is made up of a single cell. The parts of the placenta are also made up of those same cells. Therefore, the baby's genetic information is also in these parts of the placenta. In other words, these cells are like the baby's genetic twins. So this cell sample is taken and sent to a lab and analyzed to see if the baby has any genetic problems.

Who should have a CVS test?

This CVS test is not a routine test for every pregnant woman. Your doctor may recommend it if you have certain risk factors, or if you have noticed any abnormalities in a previous scan or other test.

Your doctor may tell you about this test in the following situations:

• If you already have a child with a genetic disease.
• If you are over 35 years old (at the time of conception). The risk of developing certain genetic conditions increases slightly with age.
• If the results of a previous scan or other test have shown that the baby is at increased risk of developing a genetic disease.
• If you, your husband, or anyone in your family has or has had a genetic disease.

In some cases, your doctor may advise you not to have this test. These include:

• If you have had vaginal bleeding during this pregnancy.
• If you have an infection, especially a sexually transmitted infection (STI).

What diseases can be detected with this test?

CVS mainly looks for problems with the baby's chromosomes. Chromosomes are like little packages that store our body's genetic information (DNA). If there is a change in these, such as an increase, decrease, or breakage of a chromosome, the baby may have a congenital disorder.

Here are some of the main conditions that can be detected by CVS testing:

• Down syndrome (Down syndrome or trisomy 21): This is the most talked about genetic condition among us.
• Cystic fibrosis
• Sickle cell disease
• Tay-Sachs disease
• Trisomy 18 (Trisomy 18 or Edward syndrome)
• Trisomy 13 (Trisomy 13 or Patau Syndrome)

Are there things that a CVS test can't detect?

Yes. It cannot detect all birth defects. It cannot detect things like neural tube defects (NTDs). For example, it cannot detect a problem called spina bifida. There are other tests like amniocentesis that can detect things like that.

Also, CVS cannot detect structural defects like a hole in the baby's heart or a cleft lip or palate. These can be detected with an anomaly scan, which is done between 18 and 20 weeks of pregnancy.

What happens before and during the test?

Before you schedule your test, you will meet with a genetic counselor or a genetic specialist. They will explain the benefits, risks, and the entire process to you. They will ask you any questions or concerns you may have. They will then perform a scan to determine how many weeks pregnant you are. The best day for the CVS test will be determined based on that.

How is this test done? Does it hurt?

This test is not very painful, but you may feel some discomfort. There are two main ways to do this. Your doctor will choose the best method depending on where your placenta is located.

1. Transcervical: In this, a device called a speculum is inserted into your vagina and a very thin plastic tube is passed through it through the cervix to where the placenta is. This is all done under the supervision of a scan. Then, a small sample of cells is taken from the placenta through that tube.

2. Transabdominal: In this method, a very thin needle is inserted through the skin of your abdomen, guided by a scan, into the area where the placenta is located, and a cell sample is taken. If you do this method, you will not feel much pain because a small amount of medicine is injected to numb only the area where the needle is inserted.

Either way, the entire process takes less than 30 minutes.

What happens after the test?

You will be able to go home shortly after the test is over. It is best to rest for the day. Most people can return to normal activities the next day. However, your doctor will tell you to avoid activities such as sex, exercise, and heavy lifting for two to three days.

After the test, you may have some mild stomach cramps, similar to your period. You may also have a very small amount of vaginal bleeding. This is normal. If the test was done through the abdomen, you may feel a little sore where the needle was inserted.

What are the risks and benefits of CVS testing?

As with any medical test, there is a small risk. But it is very low. We need to make a decision by comparing it with the benefits.

How long does it take for the results to come back? What if the results are positive?

After the cell sample is sent to the lab, the cells are grown and tested. Some initial results are available within a few days. However, some conditions take longer to test. So it can take 10 days to two weeks to get a full report. Your doctor or genetic counselor will call you to tell you about the results.

If the results unfortunately confirm that your baby has a genetic condition, it will be a very difficult time for you. At that time, your doctor and counselor will talk to you clearly about the condition, how it will affect your baby's future, and the options available to you. At that time, you should talk to your husband and think carefully about the next steps.

What is the difference between CVS and Amniocentesis?

Many people get these two tests confused. Amniocentesis is another test that looks at the baby's genetic condition. There are some key differences between the two.

Your doctor will explain to you which test is best for you, depending on your situation.

Questions to ask the doctor

It's normal for a lot of questions to arise in your mind when talking about a test like this. Don't hold anything back. Ask the doctor everything.

• "Do I really need to take this kind of test?"
• "Am I at higher risk of my baby having a genetic disease? Why is that?"
• "Is CVS or Amniocentesis better for me?"
• "Exactly what is the risk of miscarriage from this?"
• "What symptoms should I be concerned about after the test?"
• "What exactly can I learn from the results?"

CVS test, Chorionic Villus Sampling, pregnancy tests, genetic diseases, Down syndrome, prenatal test, placenta, baby's health