How accurate is chorionic villus sampling

Chorionic villus sampling - Results

After chorionic villus sampling (CVS) has been carried out, the sample of cells will be sent to a laboratory to be tested.

The number of chromosomes (bundles of genes) in the cells can be counted, and the structure of the chromosomes can be checked.

If CVS is being carried out to test for a specific genetic condition, the cells in the sample can also be tested for this.

Getting the results

The first results of the test should be available in about 3 days. This is known as the rapid CVS result.

A more detailed set of CVS results will be available within 2 weeks.

If the rapid CVS result and a previous ultrasound scan both indicate your baby has a condition, your doctor will discuss your options with you straightaway.

If your previous ultrasound did not find anything unexpected, it’s recommended you wait until the more detailed set of CVS results before making a decision about ending your pregnancy.

If the results of these tests suggest that it is highly likely your baby will have a genetic condition, a specialist doctor (obstetrician) or midwife will explain what the screening results mean and talk to you about your options.

There's no cure for most of the conditions found by CVS, so you'll need to consider your options carefully.

You may decide to continue with your pregnancy while gathering information about the condition so you're fully prepared.

You can usually choose whether to get the results over the phone or during a face-to-face meeting at the hospital or at home.

You'll also receive written confirmation of the results.

How reliable are the results?

CVS is estimated to give a definitive result in 99 out of every 100 women having the test.

But it cannot test for every condition and it's not always possible to get a conclusive result.

In a very small number of cases, the results of CVS cannot establish with certainty if your baby will have the condition the test is looking for.

This might be because the sample of cells removed was too small.

Or there's a possibility there's a change in the structure of the chromosomes in the placenta and not in the baby.

If this happens, it may be necessary to have amniocentesis, an alternative test where a sample of amniotic fluid is taken from the womb.

This is done a few weeks later to confirm a diagnosis.

What the results mean

Many women who have CVS will have a "normal" result. This means that none of the conditions that were tested for were found in the baby.

But as the test only checks for conditions caused by certain genes, it cannot exclude any conditions not tested for.

If a test result is "positive", in 99 out of 100 positive results the baby will have the condition tested for.

In this instance, the implications will be fully discussed with you and you'll need to decide how to proceed.

What happens if a condition is likely

If your test results shows it is highly likely that your baby will be born with a condition, you can speak to a number of specialists about what this means.

These could include a midwife, a doctor who specialises in children's health (consultant paediatrician), a geneticist and a genetic counsellor.

They'll be able to give you detailed information about the condition, including the possible symptoms your child may have, the treatment and support they might need, and whether their life expectancy will be affected, to help you decide what to do.

A baby born with 1 of these conditions will always have the condition, so you'll need to consider your options carefully.

Your options are to:

continue with your pregnancy – it can help to find out as much as you can about the condition your baby may have
end your pregnancy (have a termination)

This can be a very difficult decision, but you do not have to make it on your own.

As well as discussing it with specialist healthcare professionals, it can help to talk things over with your partner and speak to close friends and family.

You can also get support and more information from charities like:

Antenatal Results and Choices (ARC)
Down's Syndrome Association
Sickle Cell Society
SOFT UK (Support Organisation for Trisomy 13 and 18)

Page last reviewed: 03 January 2023
Next review due: 03 January 2026

Chorionic Villus Sampling: Purpose, Procedure, Risks, Results

Written by WebMD Editorial Contributors

You may be offered CVS if you have certain risk factors for having a baby with a birth defect or genetic disease, so that problems can be found early in pregnancy. Many blood screening tests for birth defects are less reliable if you're having twins. CVS can give you some clear answers. However, the risks of CVS are higher in women with twins.

What Diseases or Disorders Can CVS Identify?

CVS can help identify such chromosomal problems as Down syndrome or other genetic diseases such as cystic fibrosis, Tay-Sachs disease, and sickle cell anemia. CVS is considered to be 98% accurate in the diagnosis of chromosomal defects. The procedure also identifies the sex of the fetus, so it can identify disorders that are linked to one sex (such as certain types of muscular dystrophy that occur most often in males).

CVS does not detect open neural tube defects like spina bifida.

What Are the Benefits of CVS?

CVS can be done early in pregnancy (earlier than amniocentesis), and results are usually obtained within 10 days. Getting this kind of information early allows a woman to make choices in the beginning stage of their pregnancy. If a woman chooses to terminate the pregnancy after receiving abnormal test results, the termination will be safer than if they wait until later for amniocentesis results.

What Are the Risks of CVS?

CVS may carry a slightly higher risk of miscarriage than amniocentesis, because the procedure is done in early pregnancy. Infection may also occur. Rare cases of defects in baby's fingers or toes have been reported, especially when CVS was done before 9 weeks. This risk seems unrelated to the doctor’s experience or how the test was done. Due to this potential risk, 10 weeks is generally the earliest recommended time to perform this test.

CVS is a little trickier with twins than it is with single babies. Talk to your doctor about the risks. Make sure the doctor has a lot of experience doing CVS with twins.

Who Should Be Tested With CVS?

The American College of Obstetrics and Gynecology recommends offering CVS when there is an increased risk for a genetic disorder in the baby. This may include:

Pregnant women who will be age 35 or older on their due date (the risk of having a baby with a chromosomal problem such as Down syndrome increases with the age of the woman)
Couples who already have had a child with a birth defect or have a family history of certain birth defects
Couples with a parent known to carry a chromosomal abnormality or genetic disease
Pregnant women with other abnormal genetic test results

Your health care provider can advise you on whether this test is right for you. In the end, only you and your partner can decide whether you should have this test performed.

How Is the CVS Test Performed?

Before undergoing a CVS prenatal test, appropriate genetic counseling, including a detailed discussion regarding the risks and benefits of the procedure, are recommended.

At the time of initial consultation and counseling, an ultrasound exam will be performed to confirm gestational age (the development stage of the embryo) and the location of the placenta. This is done so that CVS can be performed at the appropriate gestational age (which is usually 10 to 12 weeks from the woman's last menstrual period).

There are two ways to collect chorionic villi from the placenta: through the vagina or through the abdomen.

To collect cells through the vagina, a speculum is inserted (in the same way as a Pap test). Then a very thin, plastic tube is inserted up the vagina and into the cervix. Using ultrasound images, the tube is guided up to the placenta, where a small sample is removed.

To collect cells through the abdomen, a slender needle is inserted through the woman's abdomen to the placenta, much like in amniocentesis.

The sample of chorionic villi is then sent to a lab, where the cells are grown in a special fluid and tested a few days later. Culture results will be available within 2 weeks. Your doctor will notify you of the results.

Will the CVS Test Be Painful?

It could be, but it's over relatively quickly. The test takes no longer than a half hour from start to finish. The extraction itself runs only a few minutes.

What Happens After the CVS Test?

You'll need to take it easy immediately after a CVS test, so arrange for someone to drive you home. For the rest of the day, you'll need to rest. Generally, women are advised to abstain from strenuous physical activity, sex, and exercise for 3 days following the procedure. You may have some cramping and bleeding, which is normal, but do tell your doctor or midwife. If you notice fluid leaking from your vagina, call your health care provider immediately.

What to Know About Test Results

You should get test results in about 1 week. CVS is very accurate. If there is a problem, you can meet with a genetic counselor and talk about your options.

Chorion biopsy procedure: essence and preparation

Pregnancy is always an unforeseen and sometimes difficult process. It happens that in order for it to pass calmly and comfortably for future parents, it is necessary to do some research. They will be able to show if the baby has any abnormalities. And depending on the results, parents will be able to decide whether to continue the pregnancy. One of the most important studies is the chorionic biopsy procedure. nine0003

What is the purpose of the procedure?

Chorionic biopsy is one of the most modern methods of prenatal diagnosis, which allows to identify genetic disorders in the fetus. This is an invasive diagnosis. With it, a special needle is inserted through the wall of the abdominal cavity or through the cervix, with which biological material is taken from the chorion (future placenta). This organ has the same chromosomal material as the embryo. That is why a biopsy helps to find out accurate information about the unborn child. At the same time, without affecting it and conducting research only with the help of tissues taken from the future placenta. nine0003

There are two types of chorionic villus biopsy:

Transcervical biopsy – a needle is inserted through the cervix.
Abdominal biopsy - the needle is inserted through the abdomen.

Both one and the second method are very informative and able to indicate the presence or absence of genetic problems with an accuracy of 99%. But which research method to choose depends on the location of the chorion.

What is the purpose of the procedure?

Chorionic biopsy is a voluntary test. It is not mandatory for everyone. It is carried out only at the request of future parents. But this method of prenatal diagnosis sets itself very specific goals. They consist in identifying:

Down syndrome, Turner, Edwards.
Klinefelter syndrome.
Hemophilia.
Amavrotic idiocy.
Sickle cell anemia.
Other rarer genetic diseases.

What are the indications for testing?

This procedure is not for everyone. It is carried out exclusively under certain circumstances, but they cannot serve as a mandatory reason to carry out the study. It should only be done with parental consent. So, the indications for a chorionic biopsy can be as follows:

Mother of a child over 35 years of age. It has been proven that after this age, the risk of having a child with Down syndrome increases every year. It is especially important to undergo this study if a pregnant woman is older than 40-45 years.
If the couple who is expecting a baby is an older one. For example, the mother is over 35 years old, the father is 40. The older both parents are, the greater the risk of having a baby with various genetic abnormalities.
If prenatal screening has identified a high risk of having a child with various genetic diseases. This can usually be suspected if a blood test for certain hormones shows poor results. Then additional studies may be prescribed, one of which is a chorion biopsy. Sometimes some syndromes can be suspected during an ultrasound examination. For example, inconsistencies of the nasal bone with the gestational age or other abnormal inconsistencies that can be noticed by an uzist. nine0018
If there is an urgent need to know the exact gender of the baby. This is the case if a genetic disorder that is only found in girls or only in boys is suspected (eg, hemophilia).
In the case when the family already has one child with genetic "breakdowns".
When one of the relatives suffered from genetic diseases.
If a doctor suspects a genetic disorder during routine ultrasound.

It should be noted that even in the presence of such problems, there is no guarantee that the child will be sick or born with some genetic problems. Carrying out a biopsy of the chorion is currently only advisory. No doctor can force a future mother to undergo such a study. In addition, this is a rather expensive procedure and not every clinic can perform it. nine0003

Are there any contraindications?

Chorionic villus sampling, like any procedure, has its contraindications. In some cases, it cannot be done, otherwise it can harm the mother or child. These are situations when:

There is an exacerbation of chronic diseases in the mother.
The threat of miscarriage persists.
The uterus is in constant tone.
There is a curved cervix
A woman has bleeding from the vagina.
There are uterine fibroids.
Diagnosed adhesions in the pelvic organs.
If a woman is expecting twins.
In case there is no possibility of normal access to the chorion.

In some of the situations listed above, a biopsy may be performed after symptoms are relieved or there is no threat of miscarriage. And in some, like fibroids or multiple pregnancies, such a procedure cannot be done at all.

When to do the procedure? nine0011

The timing of the chorion biopsy is quite specific. The most optimal are the periods from 11 to 13 weeks. According to research, it is precisely at these times that the presence of genetic abnormalities can be accurately established. But sometimes such a procedure can be done from the 9th to the 12th week.

Sometimes it happens that the period for applying this method can be "stretched" from the 10th to the 19th week. This happens in purely individual cases, and only a doctor can choose the most optimal time to do this study. nine0003

From a psychological point of view, it is best to take a biopsy before the 12th week. After all, if a negative diagnosis is confirmed, then it will be much easier and less painful to terminate such a pregnancy at an earlier date than to do a similar procedure at a later period.

What are the steps for performing a biopsy?

The procedure must be carried out in specialized clinics. It does not require a woman to stay in a hospital, but at the same time, it should be done only according to strict indications and after all the necessary tests. Preparation for a chorion biopsy includes an ultrasound of the pelvic organs (to accurately find out the number of fetuses), to understand exactly where the chorion is located. Also taking blood, urine and vaginal smear tests. In addition, the Rh factor and blood type must be accurately established. nine0003

The procedure can be performed through the abdominal wall or through the cervix. This is decided by the doctor.

If the examination is done through the abdominal wall, the puncture site must be lubricated with an antiseptic. Then the abdominal cavity is pierced with a special needle and biological material is taken from the chorion. It needs quite a bit, but at the same time the information content is very high.

If the examination is performed transcervically, the cervix is also lubricated with an antiseptic. Then the doctor takes a piece of tissue for examination with a special probe. nine0003

For all biopsy procedures, an ultrasound doctor must be present, who can control the process with the help of an ultrasound machine.

After the examination, the woman can lead a normal life, although on the first day after the biopsy she should limit physical activity, intimate life and be especially attentive to herself.

Are the results accurate?

Biopsy is a relatively new method of prenatal diagnosis. But she has established herself as one of the most accurate and reliable ways. Chorionic biopsy results almost always show an accuracy of 9nine%.

All biological materials after they have been taken are placed in a special environment. Then they go to the laboratory. There, experienced specialists conduct research using the most modern methods and methods that allow you to make a qualitative analysis for genetic abnormalities.

Preliminary results can be known after 3 days, and the final and exact results become known after about 10 days. Sometimes it happens that due to the complexity of the analysis, the result may be uncertain. Then you need to undergo another biopsy at 16 weeks. nine0003

A biopsy is only accurate for the presence or absence of certain genetic diseases. But this method cannot give an absolute guarantee that the child will be born absolutely healthy without any other deviations.

Can there be complications?

This procedure is not completely safe. This is an invasive method that can have its negative consequences. But they are found only in rare cases. Only 2-3% of women can have serious troubles. But at the same time, complications after a chorionic biopsy are as follows:

Abdominal pain in a woman during the first few days after the procedure. If these are small cramping discomforts, this should not be feared. It'll all be over in a couple of days.
Amniotic fluid may leak in the early days.
Membrane integrity may be compromised.
Intrauterine infection of the fetus sometimes occurs.
Severe bleeding may occur.
Spontaneous miscarriage can sometimes occur. nine0018

According to statistics, only 0.4% of women can miscarry after a biopsy. And often this happens when the diagnosis for the presence of genetic defects is confirmed. Thus, there is a kind of "natural selection". In other cases, the risk of complications is minimal. But in any case, if after the procedure a woman has severe pain, bleeding or abundant watery discharge, it is necessary to urgently consult a doctor.

How much does it cost?

The biopsy procedure is not cheap, but it should be done only in trusted clinics that have all the necessary equipment and specialists. Chorionic biopsy price in Kyiv is quite affordable at the IPF clinic. Here you will receive high-quality services and at the same time you can be sure that the procedure will be carried out by highly qualified specialists. In addition, the constant support of a doctor, friendly staff and the most modern equipment will allow you to be confident and calm, focused on getting a good result. nine0003

If you are interested in chorion biopsy in Kyiv, always contact only trusted clinics, because this procedure requires special knowledge, equipment and skill.

Chorionic biopsy is an opportunity to understand whether the unborn baby is healthy. It has certain risks, but at the same time it allows you to determine the presence of incurable genetic diseases. This method gives parents a chance to choose whether to terminate or continue the pregnancy, prepare for the birth of a special child, or simply enjoy the pregnancy happily, knowing that the baby will be born healthy and without pathologies. nine0003

Chorionic biopsy | Ida-Tallinna Keskaigla

The purpose of this leaflet is to provide the patient with information about the purpose, nature and risks of chorionic biopsy.

Chorionic biopsy is performed on pregnant women whose primary tests (OSCAR test, NIPTIFY, Panorama or twin test) indicate a possible increased risk of a chromosomal disorder or whose history indicates the possibility of a hereditary disorder.

Chorionic biopsy is a voluntary procedure and you can decide for yourself whether you want to have this procedure or not. Before the study, it is necessary to sign an informed voluntary consent to the procedure. nine0003

Please note that the procedure takes two to three hours.

How is a chorion biopsy performed?

In the case of a chorionic biopsy, the cells of the chorionic villi, that is, the developing placenta, are examined. The chromosomes contained in the chorion cells coincide with the cells of the fetus. In order to examine these cells, a small piece of placental tissue is taken through the abdominal wall under ultrasound guidance with a thin needle. The collected material is sent to the laboratory for analysis. nine0003

When is the best time to do a chorionic biopsy?

Chorionic biopsy is usually performed from the 12th week of pregnancy, but may be performed later. The safest are the 12-13th weeks of pregnancy.

Is the examination painful?

The test can be uncomfortable, but most women find it no more painful than drawing blood from a vein. After the test, you may experience some spotting and you may feel some tension in your abdomen, which is normal. If the bleeding increases, you should immediately consult a doctor. nine0003

What are the risks associated with a chorionic biopsy?

Chorionic biopsy is a common test and complications are rare. For most women, the importance of the information obtained from the study far outweighs the risks of the study.

Chorion biopsy increases the risk of miscarriage by 1–2%. The vast majority of pregnancies continue without problems.
Chorionic biopsy is performed under sterile conditions to prevent inflammation, but in spite of this, inflammation can occasionally develop, which is manifested by fever, uterine contractions, and abdominal pain. nine0003
In Rh-negative women, chorionic biopsy carries the risk that fetal blood cells enter the pregnant woman's bloodstream and develop antibodies to them. In order to prevent this, after the study, a pregnant woman is given an injection of antibodies, which reduces the risk of an Rhesus conflict.
Occasionally, chorionic biopsy (more often than amniocentesis) produces cells unsuitable for examination. In this case, a second chorionic biopsy or amniocentesis (amniotic fluid analysis) is suggested.
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