CVS can be used to diagnose a number of conditions, including: Down's syndrome — all children born with Down's syndrome have some degree of learning disability and delayed development, but this varies widely between children Edwards' syndrome and Patau's syndrome — conditions that can result in miscarriage , stillbirth or severe physical problems and learning disabilities cystic fibrosis — a condition where the lungs and digestive system become clogged with thick, sticky mucus Duchenne muscular dystrophy — a condition that causes progressive muscle weakness and disability thalassaemia — a condition that affects the red blood cells, which can cause anaemia , restricted growth and organ damage sickle cell disease — where the red blood cells develop abnormally and are unable to carry oxygen around the body properly phenylketonuria — where your body cannot break down a substance called phenylalanine, which can build up to dangerous levels in the brain 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 before deciding whether to have it. Reasons to have CVS CVS will usually tell you for certain if your baby will or will not be born with any of the conditions that were tested for.
Reasons not to have CVS Miscarriage can happen. Up to 1 out of every people who have CVS will miscarry. Find out more about the complications of CVS You may choose to have an alternative test called amniocentesis later in your pregnancy instead. You can resume your normal activity level after the procedure. However, you might consider avoiding strenuous exercise and sexual activity for a day. Meanwhile, the tissue sample will be analyzed in a lab.
Results might take a few days to a week or so, depending on the complexity of the lab analysis. Your health care provider or a genetic counselor will help you understand your chorionic villus sampling results. Occasionally, test results are unclear and amniocentesis — another prenatal diagnostic test — is needed to clarify the diagnosis.
With chorionic villus sampling, there's a rare chance of a false-positive test — when the test is positive, but no disease exists. It's also important to remember that chorionic villus sampling can't identify all birth defects, including spina bifida and other neural tube defects. If chorionic villus sampling indicates that your baby has a chromosomal or genetic condition that can't be treated, you might be faced with wrenching decisions — such as whether to continue the pregnancy.
Seek support from your health care team and your loved ones during this difficult time. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version.
Overview Chorionic villus sampling Open pop-up dialog box Close. Chorionic villus sampling During chorionic villus sampling, a thin tube is guided through the cervix shown above or a needle is inserted into the uterus to remove a sample of chorionic villus cells from the placenta. Request an Appointment at Mayo Clinic. Share on: Facebook Twitter. The doctor will insert an instrument called a speculum into your vagina so that he or she can see your cervix. Cells will be gently suctioned through the tube into a syringe.
You may feel a twinge or slight cramping. More than one sample may be needed to obtain enough tissue for testing. For an abdominal CVS, your abdomen will be cleansed with an antiseptic. You will be instructed not to touch the sterile area on your abdomen during the procedure. The doctor may inject a local anesthetic to numb the skin. If a local anesthetic is used, you will feel a needle stick when the anesthetic is injected. This may cause a brief stinging sensation. Ultrasound will be used to help guide a long, thin, hollow needle through your abdomen and into the uterus and placenta.
This may be slightly painful, and you may feel a cramp as the needle enters the uterus. Cells will be gently suctioned into a syringe. The needle will then be removed. An adhesive bandage will be placed over the abdominal needle insertion site. If you are Rh negative, you may be given Rho D immune globulin.
This is a specially developed blood product that can prevent an Rh negative mother's antibodies from reacting to Rh positive fetal cells. You and your fetus will be monitored for a while after the procedure.
Your vital signs and the fetal heart rate will be checked periodically for an hour or longer. The CVS tissue will be sent to a specialty genetics lab for analysis.
Counseling with a genetics specialist may be recommended depending on the test results. You should rest at home and avoid strenuous activities for at least 24 hours. It involves removing and testing a small sample of cells from the placenta, the organ linking the mother's blood supply with the unborn baby's.
It's only offered if there's a high chance your baby could have a genetic or chromosomal condition. It's important to remember that you do not have to have CVS if it's offered. It's up to you to decide whether you want it. A midwife or doctor will speak to you about what the test involves, and let you know what the possible benefits are, to help you make a decision. Find out more about why CVS is offered and deciding whether to have it. CVS is usually carried out between the 11th and 14th weeks of pregnancy, although it's sometimes performed later than this if necessary.
The test itself takes about 10 minutes, although the whole consultation may take about 30 minutes. The CVS procedure is usually described as being uncomfortable rather than painful, although you may experience some cramps that are similar to period pains for a few hours afterwards.
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