Chorionic Villus Sampling (CVS)
Chorionic Villus Sampling, commonly known as CVS, is a prenatal diagnostic procedure used to examine a small sample of placental tissue. It can provide diagnostic information about certain chromosomal and genetic conditions during pregnancy and is usually performed in the first trimester under continuous ultrasound guidance.
Chorionic Villus Sampling is an invasive prenatal diagnostic test in which a small sample of chorionic villi is collected from the placenta. These cells contain genetic material that can be analysed for specific chromosomal or genetic conditions.
CVS may be offered when there is an increased chance of a chromosomal or genetic condition. It may be considered after a high-risk prenatal screening result, an ultrasound finding suggesting a possible genetic condition, a previous pregnancy affected by a chromosomal or inherited disorder, or a known family history of a specific genetic condition.
CVS can provide diagnostic information about common chromosomal conditions including Down Syndrome (Trisomy 21), Edwards Syndrome (Trisomy 18) and Patau Syndrome (Trisomy 13). Depending on the clinical indication, additional chromosome or genetic testing may also be performed.
NIPT or cell-free DNA testing is a screening test and not a diagnostic test. If NIPT indicates a high chance of a chromosomal condition, CVS may be discussed as an option for diagnostic confirmation when the pregnancy is at an appropriate gestational age.
Certain fetal structural findings identified during an ultrasound examination may increase the possibility of a chromosomal or genetic condition. In such situations, CVS may provide additional diagnostic information and help determine whether an underlying genetic condition is present.
CVS is generally performed during the first trimester, commonly between 11 and 13 weeks of pregnancy. The exact timing depends on gestational age, fetal and placental position, the reason for testing and the type of genetic analysis required.
Before CVS, an ultrasound examination is performed to confirm the pregnancy, assess fetal wellbeing and determine the position of the placenta. After the abdomen is cleaned, a fine needle is carefully guided through the abdominal wall into the placenta under continuous ultrasound visualization. A small amount of chorionic tissue is collected and sent to the laboratory for genetic testing.
Yes. Ultrasound guidance is used throughout the procedure. It allows the specialist to identify the fetus and placenta and carefully guide the sampling instrument to the appropriate area of the placenta while avoiding the fetus and other important structures.
In transabdominal CVS, a fine needle is passed through the mother's abdominal wall and uterus to reach the placenta. The needle is continuously monitored using ultrasound while a small sample of chorionic villi is collected. This is the commonly used approach when the placenta can be safely accessed through the abdomen.
The experience varies between individuals. Many women describe CVS as pressure, discomfort or period-like cramping rather than severe pain. Local anaesthetic may be used for transabdominal CVS according to the procedure and clinical practice.
The laboratory testing depends on the reason for CVS. Testing may include rapid analysis for common chromosomal conditions, conventional chromosome analysis, chromosomal microarray or targeted molecular genetic testing for a specific inherited disorder.
Rapid chromosome testing can provide early information about selected common chromosomal abnormalities. The exact chromosomes and method tested depend on the laboratory and the clinical indication for CVS.
Chromosomal microarray can identify certain small gains or losses of chromosome material that may not be detected by conventional chromosome analysis. It may be considered particularly when an ultrasound examination has identified a fetal structural abnormality or when additional genetic information is clinically appropriate.
CVS can also be used to investigate specific inherited disorders when the genetic condition and relevant familial genetic change are known. Examples can include selected blood disorders and single-gene conditions. The appropriate molecular test is chosen according to the family's genetic information.
Genetic counselling is an important part of prenatal diagnostic testing. Parents should understand why CVS is being offered, which condition is being investigated, what the test can detect, possible limitations, expected results and available alternatives before deciding whether to proceed.
NIPT is a non-invasive screening test performed using maternal blood, whereas CVS is an invasive diagnostic procedure involving placental tissue. NIPT estimates the chance of selected chromosomal conditions, while CVS can provide diagnostic information about the conditions included in the laboratory testing.
CVS and amniocentesis are both invasive prenatal diagnostic procedures, but they use different samples. CVS collects placental tissue and is generally performed earlier in pregnancy, while amniocentesis collects amniotic fluid and is generally performed after 15 weeks. The most appropriate procedure depends on gestational age, ultrasound findings and the condition being investigated.
CVS may be considered when prenatal screening indicates an increased chance of a chromosomal condition, when an ultrasound scan identifies concerning findings, when there has been a previous pregnancy affected by a genetic or chromosomal disorder, or when there is a known family history of a specific inherited condition.
CVS can be performed in selected twin pregnancies when diagnostic testing is indicated. The procedure requires detailed ultrasound planning to identify each fetus, the placental arrangement and the appropriate sampling site. The approach can vary depending on whether the twins share a placenta or have separate placentas.
CVS is an invasive procedure and carries a small risk of complications. These may include miscarriage, bleeding, infection, cramping or the need for repeat sampling if an adequate laboratory sample cannot be obtained. The individual risk depends on factors such as gestational age, pregnancy type, placental location and clinical circumstances.
CVS carries a small risk of pregnancy loss. Current patient information commonly quotes an additional miscarriage risk of approximately 0.5%, or around 1 in 200, although estimates can vary between centres and individual circumstances. Your fetal medicine specialist should explain the procedure-specific risk before testing.
Your blood group and Rh status may be checked before CVS. If you are RhD negative, anti-D immunoglobulin may be recommended after an invasive prenatal procedure according to the clinical protocol being followed.
Mild abdominal discomfort, cramping or light spotting may occur after CVS. Your fetal medicine team will provide individual instructions following the procedure. Significant abdominal pain, heavy bleeding, fluid leakage, fever or other concerning symptoms should be reported promptly to your maternity or medical team.
The timing of CVS results depends on the tests requested. Some rapid chromosome tests may provide preliminary information within a few days, while detailed chromosome, microarray or targeted genetic testing may take longer. The laboratory or fetal medicine team will explain the expected reporting time for the selected tests.
A normal CVS result provides important information about the genetic conditions examined by the laboratory. However, no prenatal genetic test can detect every possible genetic or developmental condition. Recommended ultrasound examinations and routine pregnancy care remain important.
If CVS identifies a chromosomal or genetic condition, the result can be discussed with a fetal medicine specialist and genetic counsellor. Additional ultrasound assessment may help determine whether there are associated fetal findings and can provide information for individualized pregnancy counselling and planning.
Because CVS analyses placental tissue, uncommon situations can occur in which some placental cells have a different chromosome pattern from the fetus. This is known as confined placental mosaicism. If a CVS result raises this possibility, additional assessment, which may include amniocentesis, can be discussed to clarify the fetal chromosome status.
Ultrasound assessment is an essential part of CVS. Before the procedure, the fetal position, viability, placenta and pregnancy anatomy are assessed. Ultrasound findings also help determine whether CVS or another diagnostic test is the most appropriate option.
When there is an increased chance of a genetic or chromosomal condition, early diagnostic testing can provide information during the first part of pregnancy. This may allow parents and their healthcare team more time to understand the diagnosis, consider further assessment and plan appropriate pregnancy care.
At Promise Fetal Medicine & Pregnancy Scan Centre in Jalandhar, CVS may be considered when prenatal diagnostic testing is clinically indicated. Specialist ultrasound assessment, pre-procedure counselling and guidance regarding appropriate chromosome or genetic testing can help parents understand their available options.
If you have received a high-risk NIPT result, an abnormal ultrasound finding, a positive prenatal screening result or have a family history of a genetic condition, a fetal medicine consultation can help determine whether Chorionic Villus Sampling or another prenatal diagnostic test may be appropriate for your pregnancy.
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Chorionic Villus Sampling (CVS) is a prenatal diagnostic procedure used to examine the baby’s chromosomes and certain genetic conditions. During CVS, a small sample of chorionic villi, which are placental tissue containing genetic material, is collected under ultrasound guidance. The procedure is generally performed in the first trimester, commonly between 10 and 13 weeks of pregnancy, when indicated.
Director and Chief Fetal Medicine Specialist
Baby's Journey Through Pregnancy
