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What Is Chorionic Villus Sampling?

Your first trimester of pregnancy may seem like a series of nonstop tests. From that life-changing pee stick to batteries of blood tests, ultrasounds and more, keeping up with your medical to-do list can seem overwhelming. The truth is, though, many of those tests are merely diagnostic screenings. They give you an idea of how baby is doing, but they don’t tell you anything for sure. That changes as that first trimester starts winding down—when diagnostic tests become available, should you want or need them. Among the tests? Chorionic villus sampling. Sometimes called the CVS test, it’s perhaps less recognized by non-pregnant people than the amniocentesis—but it’s just as important to have…

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Articles of Interest

Does Chorionic Villus Sampling Increase the Risk of Preeclampsia or Gestational Hypertension?

Women who underwent CVS are not at higher risk for developing hypertensive disorders than women underwent amniocentesis.

Fetal loss after amnio or CVS – what is the risk ?

The actual risk of miscarriage following amniocentesis or chorionic villus sampling (CVS) has been controversial. ACOG provides an estimated overall risk of fetal loss due to invasive testing of 0.1% – 0.3% above the background miscarriage rate. Previous papers that showed an increased rate of miscarriage included fetuses that may have been compromised or had anomalies at the time of invasive testing as the underlying indication.

Risks of chorionic villus sampling and amniocentesis

Unfortunately, spontaneous fetal loss rates are difficult to estimate, as large populations have not been followed from early pregnancy.6 Attempts to estimate background loss rates are biased by different definitions of fetal loss, variability in length of follow-up and different intervals between ultrasound assessment of viability and fetal demise.

Understanding the Risks of Chorionic Villus Sampling (CVS) and Amniocentesis in Prenatal Testing

In addition to the risk of miscarriage, other complications associated with CVS and amniocentesis include infection, bleeding, leakage of amniotic fluid, and injury to the fetus. These complications are rare but can occur, particularly if the procedures are performed by inexperienced or inadequately trained healthcare providers.

What is chorionic villus sampling?

If the CVS results are troubling, the doctor may order an amniocentesis. This is a screen test during which a sample of amniotic fluid is withdrawn. The fluid is examined for genetic abnormalities or potential birthing complications. Unlike CVS, amniocentesis cannot be performed until after the 15th week of gestation. There are valid reasons to take each test. Psychologically, CVS may be better because it allows the mother to process abnormalities earlier in the pregnancy. The main advantage of using CVS is that genetic abnormalities can be discovered during the first trimester of pregnancy. However, the risks of CVS are higher than amniocentesis risks and CVS is unable to identify certain problems.

Resources

American Pregnancy Association

Although CVS is considered to be a safe procedure, it is recognized as an invasive diagnostic test that does pose potential risks. Miscarriage is the primary risk related to CVS occurring 1 out of every 100 procedures.

Johns Hopkins Medicine

The chorionic villi are tiny projections of placental tissue that look like fingers. They have the same genetic material as the baby. Testing may be done for other genetic defects and disorders. This will depend on the family history, and on the types of lab testing that are available at the time of the procedure.

StatPearls

Chorionic villus sampling is a prenatal diagnostic procedure performed between 10 and 13 weeks of gestation to detect genetic and chromosomal conditions. The procedure involves collecting a small sample of placental tissue (chorionic villi), which contains the same genetic material as the fetus. Chorionic villus sampling offers early, definitive results for conditions such as Down syndrome and other inherited disorders.