Chorionic Villus Sampling

A Comprehensive Guide to Understanding Chorionic Villus Sampling

Last Updated on November 11, 2023 by Jasmine KeLa

What Is Chorionic Villus Sampling?

Chorionic Villus Sampling (CVS) is a prenatal diagnostic procedure that involves the removal of a small sample of cells from the placenta for genetic testing. It is typically performed between the 10th and 13th weeks of pregnancy and provides valuable information about the baby’s genetic makeup. This article explores the procedure, its benefits, risks, and alternatives, as well as its implications for expectant parents.

The Procedure

The CVS procedure involves the collection of chorionic villi, which are tiny finger-like projections found in the placenta. These villi contain the same genetic material as the fetus, making them an ideal source for genetic testing. The procedure can be performed in two ways:

Transabdominal CVS

In transabdominal CVS, a thin needle is inserted through the mother’s abdomen and into the uterus to reach the placenta. Ultrasound guidance is used to ensure accurate placement of the needle. Once the needle is in position, a small sample of chorionic villi is suctioned into a syringe. The procedure usually takes around 10-15 minutes and is performed under local anesthesia.

Transcervical CVS

Transcervical CVS involves the insertion of a narrow tube through the vagina and cervix to reach the placenta. The tube is guided by ultrasound, and a small sample of chorionic villi is collected using suction. This procedure is also performed under local anesthesia and typically takes around 10-15 minutes.

Benefits of Chorionic Villus Sampling

Chorionic Villus Sampling offers several benefits for expectant parents:

  • Early detection of genetic abnormalities: CVS can detect a wide range of genetic conditions, including chromosomal abnormalities like Down syndrome, genetic disorders like cystic fibrosis, and certain single-gene disorders. Early detection allows parents to make informed decisions about their pregnancy and prepare for the future.
  • Reduced waiting time: Unlike other prenatal diagnostic tests, such as amniocentesis, which is typically performed between the 15th and 20th weeks of pregnancy, CVS can be done earlier. This reduces the waiting time for results and provides parents with more time to plan and make decisions.
  • Increased accuracy: CVS has a high accuracy rate for detecting genetic abnormalities, with a reported accuracy of over 99%. This provides expectant parents with reliable information about their baby’s health.

Risks and Considerations

While CVS offers significant benefits, it also carries certain risks and considerations that expectant parents should be aware of:

  • Procedure-related risks: CVS is an invasive procedure, which means it carries a small risk of complications. These can include infection, bleeding, and damage to the fetus or placenta. However, the risk of these complications is relatively low, occurring in less than 1% of cases.
  • False-positive and false-negative results: Although CVS is highly accurate, there is still a small chance of receiving a false-positive or false-negative result. False-positive results can cause unnecessary anxiety and may lead to further invasive testing, while false-negative results can provide a false sense of security. It is important for expectant parents to discuss the limitations and potential outcomes with their healthcare provider.
  • Limited availability: CVS may not be available in all healthcare facilities. It requires specialized equipment and trained professionals, which may limit access for some expectant parents. In such cases, alternative diagnostic tests may be recommended.

Alternatives to Chorionic Villus Sampling

For expectant parents who are not comfortable with the risks associated with CVS or do not have access to the procedure, there are alternative diagnostic tests available:

  • Amniocentesis: Amniocentesis is a procedure that involves the removal of a small amount of amniotic fluid from the sac surrounding the fetus. It is typically performed between the 15th and 20th weeks of pregnancy and can provide similar genetic information as CVS. However, it carries a slightly higher risk of complications.
  • Non-invasive prenatal testing (NIPT): NIPT is a blood test that analyzes fetal DNA present in the mother’s blood. It can detect chromosomal abnormalities with a high degree of accuracy, but it is not able to diagnose genetic disorders or single-gene disorders.
  • Ultrasound screening: Ultrasound screenings are non-invasive and can provide valuable information about the baby’s development and potential abnormalities. While they cannot provide a definitive diagnosis, they can help identify potential issues that may require further testing.

Implications for Expectant Parents

Chorionic Villus Sampling can have significant implications for expectant parents:

  • Emotional impact: The decision to undergo CVS can be emotionally challenging for expectant parents. The procedure provides valuable information about the baby’s health but also carries a small risk of complications. It is important for parents to discuss their concerns and fears with their healthcare provider and seek support from loved ones.
  • Decision-making: The results of CVS can influence the decisions expectant parents make regarding their pregnancy. If a genetic abnormality is detected, parents may need to consider their options, such as continuing the pregnancy, preparing for the birth of a child with special needs, or considering termination. These decisions are deeply personal and should be made with careful consideration and support.
  • Preparation and support: If a genetic abnormality is detected, CVS provides parents with the opportunity to prepare for the future. This may involve seeking specialized medical care, connecting with support groups or organizations, and making necessary lifestyle adjustments. Early detection allows parents to gather information and resources that can help them navigate the challenges ahead.


Chorionic Villus Sampling is a prenatal diagnostic procedure that provides valuable genetic information about the baby. It offers early detection of genetic abnormalities, reduced waiting time for results, and increased accuracy. However, it also carries certain risks and considerations, such as procedure-related complications and the possibility of false-positive or false-negative results. Alternatives to CVS, such as amniocentesis and non-invasive prenatal testing, are available for expectant parents who prefer or require different options. The decision to undergo CVS can have emotional and practical implications for expectant parents, requiring careful consideration and support. Ultimately, the choice to undergo any prenatal diagnostic procedure should be made in consultation with healthcare professionals and based on individual circumstances and preferences.



Mother of 2 Kids , Writes for 4babystuff blog, mother who can cook and write at same time :)