What is chorionic villus sampling (CVS)?
- Chorionic villus sampling (CVS) is a type of prenatal diagnostic test to detect chromosomal problems that can result in genetic diseases and birth defects.
- It involves taking a small sample of part of the placenta (the chorionic villi) where it is attached to the wall of the uterus.
- CVS can diagnose chromosomal abnormalities that cause conditions like Down syndrome, sickle cell anemia, cystic fibrosis, and Tay Sachs disease. It does not diagnose neural tube defects.
- Because the procedure examines genetic material, it can tell you the gender of the fetus.
- CVS is performed earlier in pregnancy than amniocentesis. It is done between the 10th and 13th week of pregnancy (measured from your last menstrual period). It is reported to be 98% to 99% accurate in detecting genetic abnormalities.
- CVS can also be used to detect paternity and is 99% accurate in establishing paternity of a fetus.
How is CVS performed?
Samples for CVS are taken in one of two ways:
- Transabdominal: In this method, similar to amniocentesis, a long, thin needle is inserted through the abdominal wall into the placenta, guided by ultrasound images.
- Transcervical: With the transcervical method, a long, thin tube is passed into the vagina and up into the uterus to obtain the sample by suction. This method is most common.
The procedure can be completed in about half an hour. The actual sampling process only takes a few minutes. There may be mild discomfort when the sample is taken. After the test you may have mild cramping and bleeding, and you should rest the day of the procedure. You may be asked to abstain from sex and vigorous activity for a few days after the test. You should contact your doctor if you experience fever, heavy vaginal bleeding or cramping, or leakage of fluid from the vagina after the test.
After the sample is removed, the cells are cultured in a laboratory and analyzed. It typically takes 7 to 10 days before results are available.
What are the benefits and risks of CVS?
A major benefit of CVS is that it can be performed earlier in the pregnancy than amniocentesis, providing information about genetic defects earlier in the pregnancy. If a woman chooses termination of pregnancy, it is safer at earlier stages of pregnancy.
Miscarriage is the main risk associated with CVS and occurs in 1 out of every 100 cases. The risk of miscarriage can be slightly greater than the risk of miscarriage associated with amniocentesis. Rarely, defects in the fingers or toes of the fetus have been reported with CVS, but these cases were particularly common when CVS was done very early in pregnancy, before 9 weeks' gestation. For this reason, most cases of CVS are performed only at or after 10 weeks' gestation. Infection is another uncommon complication of CVS.
Who should receive CVS testing?
CVS testing is generally offered to women or couples who have one of the following:
- Women aged 35 or greater
- Couples with a family history of genetic disorders or birth defects
- Women with other abnormalities found in prenatal testing
Genetic counseling and a full discussion of the risks and benefits of the procedure are recommended before undergoing CVS testing.
Some women should not receive CVS testing. CVS testing is typically not recommended for:
- Multiple gestations
- Women with an active infection, such as a sexually-transmitted disease
- Women who have had vaginal bleeding during the pregnancy
Additionally, women with uterine fibroids or a tilted uterus may not be good candidates for transcervical CVS testing.
Health Solutions From Our Sponsors
REFERENCE:
American Pregnancy Association.
Chorionic villus sampling.
Top Chorionic Villus Sampling Related Articles
Abdomen Picture
The abdomen (commonly called the belly) is the body space between the thorax (chest) and pelvis. See a picture of the Abdomen and learn more about the health topic.
Achondroplasia
A common form of short stature, achondroplasia (dwarfism) is a genetic condition causing a disorder of bone growth. Complications of achondroplasia that need monitoring include (this is not all inclusive) stenosis and compression of the spinal cord, a large opening under the skull, lordosis, kyphosis, spinal stenosis, hydrocephalus, middle ear infections, obesity, and dental crowning. Achondroplasia is caused by mutations of the FGFR3 gene.
Apgar Score
The Apgar score is a method for assessing a neonate's heart rate, respiratory effort, muscle tone, skin color, and reflex irritability. Each of these signs is give a point value from 0-2. A perfect score of 10 means the infant is in excellent condition, while a score of 0-3 means the infant needs immediate resuscitation.
Birth Defects
Birth defects have many causes and currently, are the leading cause of death for infants in the first year of life. Some of the causes of birth defects include genetic or chromosome problems. Exposure of the mother to rubella or German measles during pregnancy, or using drugs or alcohol during pregnancy. The treatment for birth defects depends upon the condition of the effected child.
Cystic Fibrosis
Cystic fibrosis is a disease of the mucus and sweat glands. Cystic fibrosis is an inherited disease. The outcome of the disease leaves the body malnourished, with bulky and fouls smelling stools, vitamin insufficiency, gas, painful or swollen abdomen, infertility, susceptible to heat emergencies, and respiratory failure. There is no cure for cystic fibrosis, treatment of symptoms is used to manage the disease.
Down Syndrome Overview
Get the facts on Down syndrome, a genetic disorder caused by an additional set of chromosomes in a developing fetus. Down syndrome signs and symptoms include:- distinctive facial features,
- growth retardation, and
- decreased mental function and IQ.
Miscarriage Causes and Symptoms
Miscarriage is the medical term for the spontaneous loss of pregnancy from conception to 20 weeks gestation. Risk factors for a woman having a miscarriage include cigarette smoking, older maternal age, radiation exposure, previous miscarriage, maternal weight, illicit drug use, use of NSAIDs, and trauma or anatomical abnormalities to the uterus. There are five classified types of miscarriage: 1) threatened abortion; 2) incomplete abortion; 3) complete abortion; 4) missed abortion; and (5 septic abortion. While there are no specific treatments to stop a miscarriage, a woman's doctor may advise avoiding certain activities, bed rest, etc. If a woman believes she has had a miscarriage, she needs to seek prompt medical attention.
Pregnancy Planning (Preparing for Pregnancy)
Pregnancy planning is an important step in preparation for starting or expanding a family. Planning for a pregnancy includes:
- Taking prenatal vitamins
- Eating healthy for you and your baby
- Disease prevention (for both parents and baby) to prevent birth defects and infections
- Avoiding certain medications that may be harmful to your baby
- How much weight gain is healthy
- Exercise safety and pregnancy
- Travel during pregnancy
Pregnancy: Prenatal Care and Tests
Prenatal care is important for the health of the mother and the baby. Common prenatal tests include ultrasound, amniocentesis, screening for group B strep, and chronic villus sampling. Prenatal care also helps detect health conditions related to pregnancy, such as preeclampsia and gestational diabetes. Prenatal care costs can be expensive, but services are available to help women get the care they need.
Sickle Cell
Sickle cell anemia (sickle cell disease), a blood disease which shortens life expectancy, is cause by an inherited abnormal hemoglobin. Symptoms may include:
- bacterial infections,
- painful swelling of the hands and feet,
- fever,
- leg ulcers,
- fatigue,
- anemia,
- eye damage,
- and lung and heart injury.
Ultrasound
Ultrasound (and ultrasonography) is imaging of the body used in the medical diagnosis and screening of diseases and conditions such as:- TIAs,
- stroke,
- aneurysm's,
- heart valve irregularities,
- carotid artery disease,
- heart disease,
- gallstones,
- kidney stones,
- liver disease,
- diseases of the female reproductive, and
- diseases of the male reproductive organs.
Patient Comments
Please describe your experience with chorionic villus sampling.
Post