Pregnancy: Should I have CVS (chorionic villus sampling)?

Get the facts
Compare your options
What matters most to you?
Where are you leaning now?
What else do you need to make your decision?

1. Get the Facts

Your options

Have CVS (chorionic villus sampling).
Don't have CVS.

Key points to remember

CVS is done in the first trimester. If the test shows a serious health problem, you have more time to decide whether you want to continue your pregnancy or make plans to care for a sick child.
CVS isn't a routine test. But your doctor may recommend it if your chances of having a baby with a genetic disorder or birth defect are higher than average.
Even though CVS can find certain problems, it can't guarantee that your baby will be born healthy. No test can do that.
CVS has some risks, including a small chance of causing a miscarriage.

FAQs

What is CVS?

CVS (chorionic villus sampling) is a test that is done to see if your baby may be born with certain kinds of serious health problems.

CVS is usually done between weeks 10 and 12 of a woman's pregnancy. But it's not a routine test. Your doctor may recommend it if a fetal ultrasound and blood tests suggest that your chances of having a baby with a genetic disorder or birth defect are higher than average. Or you may already know that your chances are higher because of your age and family history.

Chorionic villi are tiny finger-shaped growths in the placenta. The genetic material in these cells is the same as that in the baby's cells. Early in your pregnancy, a doctor can take a sample of these cells and check them for certain health problems.

What information can CVS provide?

Chorionic villus sampling can tell you if your baby may be at risk for having:

A genetic disorder, such as Down syndrome.
A disease that can run in families, such as Tay-Sachs disease or hemophilia.

Even if the results from your CVS are normal, it doesn't guarantee that your baby will be born healthy. No test can do that. For example, CVS can't find many common problems, such as defects of the heart, stomach, intestines, or brain and spine (neural tube defect). A blood test (alpha-fetoprotein test) may be done early in your second trimester to check for some of these defects.

There is another test that can be done during your second trimester that looks for both genetic disorders and neural tube defects. This test is called amniocentesis. It's usually done between weeks 15 and 20 of your pregnancy. It can take 2 weeks to 1 month to get the results of amniocentesis. Results from CVS are often ready within 1 week. For more information, see the topic Amniocentesis.

Some women choose to wait until they can have amniocentesis. Others choose to have CVS in their first trimester. If it shows a serious problem, they have more time to make decisions about their pregnancy.

How is CVS done?

Chorionic villi cells can be collected in one of two ways. During the test, your doctor may:

Put a thin, flexible tube called a catheter through your vagina and cervix into the placenta. This is called transcervical CVS.
Put a long, thin needle through your belly into the placenta. This is called transabdominal CVS.

The doctor uses ultrasound to guide the catheter or needle to the right spot.

What are the benefits of having CVS?

The test can tell you if your baby may be born with certain kinds of serious health problems. Many parents are not prepared to care for a baby who is sick or has a birth defect. Information that you get from this test can help you and your partner plan for the future.

If the test finds that your baby has a genetic disorder or a birth defect, you and your partner may be faced with a tough decision about whether to continue the pregnancy. It may be helpful to talk with your doctor and a genetic counselor. They can help you understand your baby's health problem and what to expect when he or she is born.

Results from the test can also help you decide where to have your baby. If your baby will need surgery or special care, you can plan to have your baby in a hospital that has special services for newborns, such as a neonatal intensive care unit.

What are the risks of CVS?

A CVS test has some risks. You'll have to weigh the benefit of knowing if something might be wrong with your baby against the risks of having the test.

There is a small chance that the test may cause you to have a miscarriage. This means that you could lose your baby after you have the test. But when the test is done by highly trained doctors, the risk of having a miscarriage is small.

In one study of women who had CVS performed by a highly trained doctor, about 1 out of 400 women had a miscarriage after the test, while 399 did not.¹
Another study showed that 2 to 4 out of 400 women had a miscarriage after the test, while 396 to 398 did not. This greater risk may be more likely in medical centers whose doctors are less experienced in doing the test.²

Other risks include:

Infection. There is a chance that you could get an infection in your uterus.
Bleeding. There is a very small chance that you could bleed during the test. If this happens, your blood may mix with your baby's blood. This is only a problem if your blood is Rh-negative and your baby's is Rh-positive, because you could have an immune system response called Rh sensitization. If you're at risk for Rh sensitization, you'll be given a vaccine to prevent it. For more information, see the topic Rh Sensitization During Pregnancy.
Arm or leg defect.There is a chance that your baby may be born with an arm or leg defect. But this is rare, especially if the test is done after week 10 of your pregnancy.

What should you think about before having CVS?

Before you decide to have CVS, you might think about:

Your chance of passing on a family disease to your baby.
Your age. Women age 35 and older have a greater chance of having a baby with Down syndrome.
Your need to know about any problems with your baby.
What you might do if the test shows a problem.
Whether you can afford to pay for the test. CVS can cost a lot, and the test is not offered in all places. Most insurance companies will cover the cost of the test if you have certain risk factors that may increase your baby's chance of having a serious health problem. A risk factor is something—such as your age or family history—that raises your risk of having a certain health problem.

Why might your doctor recommend CVS?

Your doctor may advise you to have CVS if:

Other tests suggest that your chance of having a baby with a genetic disorder or birth defect is higher than average.
You or your partner has a family history of genetic disorders or birth defects.
You or your partner carries an abnormal gene that is known to cause a certain disease.
You already have a child who has Down syndrome or another chromosomal defect.
You want to know if your baby has a serious health problem so you can decide early whether you want to continue your pregnancy or make plans to care for a sick child.

2. Compare Options

	Have CVS	Don't have CVS
What is usually involved?	The test is usually done in a doctor's office or hospital. You lie on your back while your doctor uses an ultrasound to guide either: A thin, flexible tube (catheter) through your vagina and cervix into the placenta. A long, thin needle through your belly into the placenta. You may feel some discomfort, such as cramping, during the test. You can go home after the test.	You have regular prenatal exams and blood tests to check for any signs of problems.
What are the benefits?	You find out early in your pregnancy if your baby has a genetic disorder or birth defect. Information from the test can help you to: Decide if you want to continue your pregnancy. Make plans to care for a baby who is sick or has a birth defect. Choose a hospital that specializes in caring for newborns with serious health problems.	You avoid the cost of CVS. You avoid the risks from having CVS.
What are the risks and side effects?	Possible risks include: A miscarriage. An infection. Bleeding. An arm or leg defect in the baby.	You won't know if your baby has a severe birth defect until after he or she is born. Birth could be harder on your baby if the doctor doesn't know ahead of time that there is a problem.

Personal stories

Are you interested in what others decided to do? Many people have faced this decision. These personal stories may help you decide.

For more information, see the topics:

Personal stories about chorionic villus sampling

These stories are based on information gathered from health professionals and consumers. They may be helpful as you make important health decisions.

"My doctor talked to me about the risk of having a baby with Down syndrome. I understand that at my age, the risk starts to go up. I had a second cousin with Down syndrome, so I know what that's like. I would end the pregnancy if it turned out the baby had it, so I am going to have CVS and find out. "

— Georgia, age 35

"My doctor told me there is a risk of having a baby with problems because of my age. But testing wouldn't change my mind. It has taken me 5 years to get pregnant. I won't do anything that might cause me to lose the baby. "

— Patricia, age 39

"My husband and I are Jewish, so we had genetic testing and found out we are both carriers of Tay-Sachs disease. We will definitely have CVS to find out if our baby has it. We want children but not if they will have that awful disease. If this pregnancy doesn't work out, we will try again. "

— Sabrina, age 32

"I want to find out if my baby has any problems so I can be prepared. But no matter what, I wouldn't end the pregnancy, so I am going to wait and have amnio. I had it done with my second child. I feel more comfortable having it again instead of a different test, and I don't need to find out in the first trimester. "

— Coco, age 43

3. Your Feelings

Your personal feelings are just as important as the medical facts. Think about what matters most to you in this decision, and show how you feel about the following statements.

Reasons to have CVS

Reasons not to have CVS

I want to have the test, because I'm worried that something might be wrong with my baby.

I'm not worried that something might be wrong with my baby.

More important

Equally important

More important

I want to know if my baby has a birth defect so I have time to prepare to care for a child with special needs.

Knowing that my baby has a birth defect won't change the way I plan to care for my child.

More important

Equally important

More important

I want to know if my baby has a birth defect so I have time to decide if I want to continue my pregnancy.

Knowing that my baby has a birth defect won't change my plans to carry my baby to term.

More important

Equally important

More important

I'm not afraid of the needle or catheter that is used to do the test.

I don't like needles or catheters.

More important

Equally important

More important

I'm not worried about how much CVS costs.

I don't have insurance, and I can't afford to pay for the test myself.

More important

Equally important

More important

My other important reasons:

More important

Equally important

More important

4. Your Decision

Now that you've thought about the facts and your feelings, you may have a general idea of where you stand on this decision. Show which way you are leaning right now.

Having CVS

NOT having CVS

Leaning toward

Undecided

Leaning toward

5. Quiz Yourself

Check the facts.

1. Can a CVS test guarantee that your baby will be born healthy?

Yes
No
I'm not sure

That's right. Even though CVS can find certain problems, it can't guarantee that your baby will be born healthy. No test can do that.

2. Does CVS have some risks?

Yes
No
I'm not sure

That's right. CVS has some risks, including a small chance of causing a miscarriage.

3. Should all pregnant women have CVS?

Yes
No
I'm not sure

That's right. CVS isn't a routine test. But your doctor may recommend CVS if your chances of having a baby with a genetic disorder or birth defect are higher than average.

Decide what's next.

1. Do you understand the options available to you?

2. Are you clear about which benefits and side effects matter most to you?

3. Do you have enough support and advice from others to make a choice?

Certainty.

1. How sure do you feel right now about your decision?

Not sure at all

Somewhat sure

Very sure

2. Check what you need to do before you make this decision.

Nothing. I'm ready to take action.
I want to discuss the options with others.
I want to learn more about my options.

3. Use the following space to list questions, concerns, and next steps.

References

Citations

Caughey AB, et al. (2006). Chorionic villus sampling compared with amniocentesis and the difference in the rate of pregnancy loss. Obstetrics and Gynecology, 108(3): 612–616.
Seeds JW (2004). Diagnostic mid trimester amniocentesis: How safe? American Journal of Obstetrics and Gynecology, 191: 608–616.