Home
Bupa members

Support and offers for individual members and customers

Chorionic villus sampling Q&As

Published by Bupa's health information team, December 2008.

Answers to questions about chorionic villus sampling

This section contains answers to common questions about this topic. Questions have been suggested by health professionals, website feedback and requests via email.

 

How can I know if chorionic villus sampling is right for me?

Your doctor will explain to you the risks and benefits of having chorionic villus sampling. Only you can decide whether the test is right for you.

Explanation

Making a decision about having a diagnostic test during pregnancy can be difficult. You may be making this decision alone or with your partner.

To help make the decision that is best for you, your doctor should discuss the following information with you:

  • the types of tests available and what the results will tell you
  • the reliability of the test(s)
  • the risk of having an uncertain result and being offered a repeat procedure
  • the risk of miscarriage from having the test
  • how long the results will take
  • how you will get the results
  • your options if the baby is found to have a disorder

You may want to know more about the disorder or disorders which can be detected by chorionic villus sampling. You may also want to know more about what is involved in ending a pregnancy and how you may feel afterwards.

If you are fairly certain that you will end this pregnancy if the results are abnormal, you might want to find out as soon as possible about a disorder. In this case, you may decide that chorionic villus sampling is the best option for you.

Further information

Sources

  • Chorionic villus sampling (CVS): what you need to know. Royal College of Obstetricians and Gynaecologists, 2006. www.rcog.org.uk, accessed 2 September 2008
back to top

Will chorionic villus sampling harm my baby?

There is a small risk that you may miscarry as a result of having chorionic villus sampling test.

Explanation

Chorionic villus sampling is a test done during pregnancy. A tiny sample of tissue is removed from the placenta either by passing a fine needle through your abdomen (transabdominal) or through your cervix (transcervical). This test is only done if your baby is at risk of having a serious genetic disorder, such as Down's syndrome. It is usually done between 11 and 13 weeks of pregnancy.

The test may cause a miscarriage if the needle punctures the amniotic sac and injures the baby or introduces infection into the womb.

Up to two in 100 women who have chorionic villus sampling will miscarry as a result of this procedure. The risk is dependent on the skill of the doctor as well as technique. A more experienced doctor performing chorionic villus sampling may have a higher success rate and a lower rate of procedure-related miscarriage.

Don't shy away from asking your doctor about his or her level of experience in this technique. You can also ask the hospital or clinic the test is being performed at to see their outcomes data for chorionic villus sampling. This will give you an opportunity to see how the hospital or clinic is performing in relation to other hospitals, and their complication rate for chorionic villus sampling.

If you have any concerns about this test, speak to your doctor or midwife.

Further information

Sources

  • Amniocentesis and chorionic villus sampling. Royal College of Obstetricians and Gynaecologists, 2005, Guideline No. 8. www.rcog.org.uk
  • Chorionic villus sampling (CVS): what you need to know. Royal College of Obstetricians and Gynaecologists, 2006. www.rcog.org.uk
    • , accessed 2 September 2008
  • Fung Kee Fung K, Eason E, Crane J, et al. Prevention of Rh alloimmunization. J Obstet Gynaecol Can 2003; 25(9):765-773
back to top

What are my options if chorionic villus sampling results show a genetic disorder?

For the majority of genetic disorders, there isn't a treatment or cure. You will need to consider what is best for you and the baby.

Explanation

Chorionic villus sampling usually gives a clear result - the chromosomes are either normal or not. Your doctor will explain what the results mean. For the majority of genetic disorders, there isn't a treatment or cure.

How you choose to proceed with the pregnancy will depend on what the results mean to you, your family and your unborn child. There are several options to consider.

  • You may choose to continue with the pregnancy and use the information to prepare yourself and your family for the birth of a baby with health problems.
  • If the baby has a severe defect, you may decide to end the pregnancy (therapeutic abortion).

These decisions may be difficult. It's a good idea for you to discuss the issues with your partner, your family, your doctor and other health professionals before deciding to have chorionic villus sampling.

Further information

Sources

  • Amniocentesis and chorionic villus sampling. Royal College of Obstetricians and Gynaecologists, 2005, Guideline No. 8. www.rcog.org.uk
  • Chorionic villus sampling (CVS): what you need to know. Royal College of Obstetricians and Gynaecologists, 2006. www.rcog.org.uk, accessed 2 September 2008
back to top

Can I have chorionic villus sampling test if my blood group is rhesus (Rh)-negative and my baby is Rh-positive?

Yes, you can have the chorionic villus sampling test if you are Rh-negative and your baby is Rh-positive. You will be given an injection that helps to stop your immune system from reacting with your baby's blood.

Explanation

Your red blood cells carry many antigens on their surface. The most important of these antigens belong to the ABO system and the Rh system. The D antigen is the most important antigen of the Rh system. People with the rhesus D (RhD) antigen are referred to as RhD-positive, and those without it as RhD-negative. A baby inherits its blood type from both parents. Therefore a mother who is RhD-negative can carry a baby who is RhD-positive.

There is a risk that during an invasive procedure such as chorionic villus sampling, some of your baby's blood may enter your bloodstream. If this happens your immune system will recognise the RhD antigen on your baby's blood cells and make antibodies against it (anti-D antibodies). This process is called sensitisation or alloimmunisation.

As your pregnancy develops (or in a future pregnancy), your immune system may produce more anti-D antibodies. These may cross the placenta and bind to RhD antigen on the surface of your baby's red blood cells. The antibody-coated fetal red blood cells are removed from your baby's circulation. Your baby can develop anaemia if the red blood cells are removed faster than they are produced. Severe anaemia can cause fetal heart failure, fluid retention and swelling (hydrops), and intrauterine death.

The risk of sensitisation can be reduced if you are given an anti-D immunoglobulin before or after amniocentesis. If and when your baby's blood enters your bloodstream, the anti-D immunoglobulin neutralises the fetal antigen so that your immune system won't produce antibodies against it.

Further information

Sources

  • Routine antenatal anti-D prophylaxis for RhD-negative women - guidance 41. National Institute for Health and Clinical Excellence (NICE). August 2008. www.nice.org.uk
  • Fung Kee Fung K, Eason E, Crane J, et al. Prevention of Rh alloimmunization. J Obstet Gynaecol Can 2003; 25(9):765-773
back to top

Related topics

back to top

This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.

Publication date: December 2008

 

Rate this page

Up to £100 off a Bupa Health assessment

Bupa health insurance

Free online health check

Bupa Care Homes

Bupa travel cover