As part of high-quality prenatal care, certain diagnostic tests may be offered to expectant mothers based on individual medical history, age, or screening results. One of those tests is Chorionic Villus Sampling (CVS) — a procedure that provides early insight into your baby’s genetic health.
This article explains what CVS is, why it may be recommended, how it’s performed, and what risks and benefits to consider, so you can feel informed and confident if this test becomes part of your pregnancy journey.
🧬 What Is Chorionic Villus Sampling (CVS)?
Chorionic Villus Sampling is a prenatal diagnostic test in which a small sample of the placenta (chorionic villi) is taken to test for genetic and chromosomal conditions. The test is typically performed between 10 and 13 weeks of pregnancy, making it one of the earliest diagnostic options available.
The chorionic villi often contains the same genetic material as the fetus, which allows testing for certain conditions before many other assessments can be done.
🩺 Why Is CVS Done?
CVS is not part of routine care and is usually offered when there’s a higher risk of a genetic condition, or when parents desire an early diagnosis. It may be recommended in the following situations:
- Abnormal results from a first-trimester screening or NIPT
- Maternal age 35 or older (increased risk of chromosomal abnormalities)
- Family history of genetic disorders
- A prior pregnancy affected by a genetic condition
- Carrier status of either parent for certain inherited diseases
🧪 What Can CVS Detect?
CVS can diagnose a number of genetic and chromosomal conditions, including:
- Down syndrome (Trisomy 21)
- Trisomy 18 and Trisomy 13
- Cystic fibrosis
- Tay-Sachs disease
- Sickle cell disease
- Other inherited single-gene disorders (depending on family history)
CVS does not detect neural tube defects like spina bifida. If that information is needed, a second-trimester blood test or an amniocentesis may be offered later in pregnancy.
🧷 What Happens During the Procedure?
CVS is performed by a skilled provider under continuous ultrasound guidance, either transabdominally or transcervically, depending on the position of the placenta.
The procedure involves:
- Locating the placenta via ultrasound
- Cleaning the skin or cervix, depending on the approach
- Using a thin needle (through the abdomen) or a small catheter (through the cervix) to collect a tiny sample of placental tissue
- Sending the sample to a specialized lab for analysis
The procedure typically takes about 15–30 minutes, with most of that time spent preparing and locating the sample site. The actual collection takes just a few minutes.
⚠️ What Are the Risks?
CVS, like all procedures, carries some risks:
- Miscarriage (estimated risk is about 1 in 300 to 1 in 500)
- Cramping or light bleeding
- Infection (rare)
- Rh sensitization (prevented with Rhogam if the mother is Rh-negative)
- Limb abnormalities (very rare and primarily associated with procedures done before 10 weeks)
CVS is not offered before 10 weeks, and each situation is carefully evaluated to determine whether the benefits outweigh the risks.
✅ What Are the Benefits?
The main benefit of CVS is that it allows for early, definitive information about your baby’s genetic makeup — earlier than amniocentesis.
Benefits include:
- Early diagnosis of chromosomal or genetic conditions
- More time to make decisions and plan care
- Ability to prepare emotionally, medically, and logistically
- In some cases, CVS results may offer reassurance after abnormal screening tests
🤝 Making the Decision
CVS is a personal choice. Some families want definitive answers early; others prefer non-invasive testing or may opt to wait for second-trimester assessments.
Your healthcare team is here to provide clear, balanced information to help you decide what’s right for you and your baby. We’ll review your risk factors, explain your options, and support whatever choice you make.
💬 Have Questions? Let’s Talk.
If CVS has been offered to you, know that it’s part of a careful, evidence-based approach to prenatal care. We’ll walk through everything together — from the science to the emotional side — to help you feel supported and informed.
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