The team includes a specialist doctor, midwife and other health professionals. The team, which could be based in another hospital, may offer you further tests and will give information and advice about any health conditions or chromosomal conditions you or your baby might have. As well as discussing it with specialist healthcare professionals, talk things over with your partner and speak to close friends and family, if you think it might help. Before you decide to have chorionic villus sampling CVS , you'll be told about the risks and possible complications.
CVS carries a risk of miscarriage , which is the loss of a pregnancy within the first 23 weeks. However, it's difficult to determine which miscarriages would have happened anyway, and which are the result of the CVS procedure. Some recent research has suggested that only a very small number of miscarriages that occur after CVS are a direct result of the procedure. In most cases, miscarriages linked to CVS occur within two weeks of the procedure. There's no evidence to suggest you can do anything during this time to reduce your risk.
The risk of miscarriage after CVS is considered to be slightly higher than after an alternative test called amniocentesis , which is carried out slightly later in pregnancy. This could be because not enough cells were taken, or because the sample was contaminated with cells from the mother. If the sample is unsuitable, it may be necessary for the CVS procedure to be carried out again, or to wait a few weeks to have amniocentesis instead.
As with all types of surgical procedures, there's a risk of infection during or after CVS. Infection can occur if there are bacteria on your skin or on the instruments being used.
This is where some of your baby's blood enters your bloodstream and your body starts to produce antibodies to attack it. If it's not treated, this can cause the baby to develop rhesus disease. If you don't already know your blood type, a blood test will be carried out before CVS to see if there's a risk of sensitisation.
An injection of a medication called anti-D immunoglobulin can be given to stop sensitisation occurring, if necessary. Home Tests and treatments Biopsies Chorionic villus sampling. Chorionic villus sampling See all parts of this guide Hide guide parts 1.
Overview 2. Why it's offered 3. What happens during chorionic villus sampling 4. Results 5. Overview Chorionic villus sampling CVS is a test you may be offered during pregnancy to check if your baby has a health condition or chromosomal condition. This could be because: an earlier antenatal screening test has suggested there may be a health condition or chromosomal condition, such as Down's syndrome , Edwards' syndrome or Patau's syndrome or sickle cell anaemia you've had a previous pregnancy with these health conditions or chromosomal condition you have a family history of a health condition, such as cystic fibrosis or muscular dystrophy, and a health condition is detected in your baby during a routine ultrasound scan It's important to remember that you don't have to have CVS if it's offered.
How CVS is performed CVS is usually carried out between the 11th and 14th weeks of pregnancy, although it's sometimes performed later than this if necessary. During the test, a small sample of cells will be removed from the placenta using one of two methods: transabdominal CVS — a needle is inserted through your tummy this is the most common method used transcervical CVS — a tube or small forceps smooth metal instruments that look like tongs are inserted through the cervix the neck of the womb The test itself takes about 10 minutes, although the whole consultation may take about 30 minutes.
Getting your results The first results of the test should be available within three working days and this will tell you whether a health condition or chromosomal condition has been discovered. What are the risks of CVS? Before you decide to have CVS, the risks and possible complications will be discussed with you. What are the alternatives? Why it's offered Chorionic villus sampling CVS is offered to pregnant women at risk of having a baby with a health condition or chromosomal condition.
You don't have to have the test if it's offered — it's up to you to choose whether you want it. What health conditions can CVS detect? CVS can be used to diagnose a number of health conditions, and chromosomal conditions including: Down's syndrome Edward's syndrome Patau's syndrome cystic fibrosis Duchenne muscular dystrophy thalassaemia sickle-cell anaemia phenylketonuria CVS cannot detect neural tube defects. Deciding whether to have CVS If you're offered CVS, ask your doctor or midwife what the procedure involves and what the risks and benefits are before deciding whether to have it.
Reasons to have CVS The test will usually tell you whether your baby will be born with any of the health conditions or chromosomal conditions that were tested for. What happens during chorionic villus sampling Chorionic villus sampling CVS involves taking a sample of cells from the tissue of the placenta the 'chorionic villi'. You may want to bring a partner, friend or family member for support when you have the test. Transabdominal CVS Your tummy is first cleaned with antiseptic before a local anaesthetic injection is used to numb it.
Transcervical CVS A sample of cells from the chorionic villi is collected through your cervix the neck of the womb. Which method will be used?
The transabdominal method is preferred in most cases, because it's often easier to carry out. Is CVS painful? CVS is usually described as being uncomfortable, rather than painful. Transcervical CVS feels similar to a cervical screening test. How long does it take? Women age 35 and older have a higher risk of having a baby with Down syndrome or another genetic disorder. Family history of a genetic disorder Having another child with a genetic disorder You may also need CVS testing if you had abnormal results on a prenatal screening test.
What happens during a CVS test? The sample is taken through the cervix. The cervix is the lower, narrow end of the uterus that opens into the vagina. During a transabdominal CVS, your provider will: Clean your abdomen with an antiseptic. Apply a numbing medicine to your abdomen. Insert a long, thin needle through your abdomen and uterus and into the placenta.
You may feel a cramping or stinging sensation as the needle enters the uterus. Use the needle to withdraw a sample of tissue from the placenta. Remove the needle. During a transcervical CVS, your provider will: Clean your vagina and cervix with an antiseptic Use an instrument called a speculum to gently spread apart the sides of your vagina.
Insert a thin tube through your vagina and cervix and up to the placenta. You may feel a slight twinge or cramping as this is done. Use the tube to gently suck in a sample of tissue from the placenta. Remove the tube. Will I need to do anything to prepare for the test? Are there any risks to the test? CVS is generally considered to be a safe procedure, but it does have some risks.
These include: Miscarriage , which happens in about one in every hundred procedures Infection Bleeding Rh sensitization. This is a condition in which your body makes antibodies proteins made by the immune system that attack your baby's red blood cells.
If diagnosed during pregnancy, it is easily treatable. Limb defects in the baby this is very rare. What do the results mean? CVS test results are usually available within two weeks.
If you have questions about your results, talk to your health care provider. Is there anything else I need to know about CVS testing? References American Pregnancy Association [Internet]. This quicker result is an additional test on the same specimen with an additional charge, but does not exclude all chromosomal abnormalities. Sometimes when a specific abnormality is suspected, it can be beneficial in expediting certain obstetric management decisions.
The decision to have a CVS is often a difficult and stressful one to make. It is important that the patient and her partner have fully discussed the issues prior to having the procedure done.
They should discuss this amongst themselves and with their doctor. The decision to request such a test as CVS should only be made when the couple feels fully informed and understand what is involved.
Pre-test genetic counselling will enable you to speak to a specifically trained genetic counsellor or radiologist prior to having the CVS. Issues you can expect to discuss will include:. Not all abnormalities can be diagnosed with CVS. Only chromosome abnormalities and, when specifically tested for certain genetic disorders, can be diagnosed.
Hence, if the chromosome result is normal, this does not guarantee a normal baby. It does, however, exclude major chromosomal abnormalities in the fetus. Results of CVS are very accurate but occasionally the results can be very difficult to interpret. In such circumstances further chromosome testing may be required. CVS is most commonly performed to determine whether or not the fetus has Down syndrome or another major chromosomal abnormality present.
Occasionally, a rare chromosome abnormality may be found. This will usually best be explained to you by a geneticist who is a specialist doctor. The accuracy of a specific test will depend on the specific inherited genetic disorder and will be discussed by the genetic counsellor or your doctor. In about 1 in 1, CVS procedures, the placental cells fail to grow. This is not due to a failure of the needle test or pathology laboratory.
Rather, it is just a fact that some placental chorionic villi fail to grow outside the body in the special laboratory environment.
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