Chorionic villus sampling

If you have the test:

• About 1 in every 200 women
  The spontaneous loss of a pregnancy before 24 weeks' gestation.
  miscarry
  following the test
• Less than 1 in every 1000 women develop an infection
• Occasionally a CVS cannot give us any result, or the abnormality is only in the placenta (this is called
  There is a difference between the chromosomal makeup of the cells in the placenta and the cells in the baby. CPM is found in 1-2% of women who have a CVS.
  confined placental mosaicism
  ) and not in the baby – in these cases, we would offer you an
  Collection of amniotic fluid using a specialised needle inserted through the abdomen under ultrasound guidance to investigate whether your baby has a chromosomal or genetic disorder.
  amniocentesis
  ).

It is not always possible to get a result from the first CVS. Up to 6 in 100 women (6%) will be offered a second procedure.

One in 200 women who have a CVS or amniocentesis will miscarry. We do not know why some women miscarry after these procedures. Most miscarriages happen within 3 days of the procedure, but they can happen up to 2 weeks afterwards. There is nothing you can do to prevent a miscarriage after a CVS or amniocentesis.

There is a risk of less than 1 in 1,000 that a CVS will cause a serious infection. You should call your midwife or doctor, or the hospital where you had the test, straight away if you experience any of the following symptoms:

• persistent or severe pain
• a high temperature of 38°C (100.4°F) or more
• chills or shivering
• heavy vaginal bleeding
• discharge of clear fluid from the vagina
• contractions

If you have the test you can find out early in your pregnancy if your baby has a genetic disorder or birth defect, which can help you:

• Decide if you want to continue your pregnancy.
• Prepare yourself to care for a baby who may have long term health (which may include surgery), social and educational needs.
• Meet with healthcare professionals who specialise in caring for newborns with serious health problems.
• There may be a support group that you can contact such as the Down’s syndrome Association or the Antenatal Choices and Results (ARC) charity.

If you don’t have the test you do not expose yourself to the risks associated with the procedure, such as miscarriage or infection.