Chorionic Villus Sampling (CVS)

Chorionic villus sampling (CVS) is a prenatal test that involves removing a small sample of cells from the placenta, specifically from the chorionic villi, to diagnose certain genetic disorders or chromosomal abnormalities in the fetus.

Procedure

The CVS procedure typically takes place between 10 and 12 weeks of pregnancy. There are two methods of performing CVS:

• Transcervical CVS: A catheter is inserted through the cervix and guided to the placenta using ultrasound. The catheter is then used to remove a small sample of chorionic villi.
• Transabdominal CVS: A needle is inserted through the abdomen and guided to the placenta using ultrasound. The needle is then used to remove a small sample of chorionic villi.

Purpose

The primary purpose of CVS is to diagnose genetic disorders or chromosomal abnormalities, such as:

• Down syndrome (trisomy 21)
• Cystic fibrosis
• Sickle cell disease
• Tay-Sachs disease
• Other genetic disorders

Risks and Complications

As with any invasive medical procedure, there are risks and complications associated with CVS, including:

• Miscarriage (less than 1% risk)
• Infection
• Bleeding or spotting
• Rh sensitization (if the mother is Rh-negative)

Benefits

The benefits of CVS include:

• Early diagnosis of genetic disorders or chromosomal abnormalities, allowing for informed decision-making about the pregnancy
• A high degree of accuracy (greater than 99%) in detecting certain genetic disorders
• The ability to perform the test earlier in pregnancy compared to amniocentesis (typically performed between 15 and 20 weeks)

Results

The results of CVS are typically available within 1-2 weeks. The test can detect:

• Chromosomal abnormalities, such as aneuploidy (having an abnormal number of chromosomes)
• Genetic disorders caused by mutations in specific genes

Alternatives

Alternative prenatal tests include:

• Amniocentesis
• Non-invasive prenatal testing (NIPT)
• Maternal serum screening (MSS)

Conclusion

Chorionic villus sampling (CVS) is a valuable prenatal test for detecting genetic disorders or chromosomal abnormalities in the fetus. While it carries some risks and complications, the benefits of early diagnosis and high accuracy make it an important tool for informed decision-making about the pregnancy.

Frequently Asked Questions (FAQs)

What is Chorionic Villus Sampling (CVS)?
A prenatal test that involves removing a sample of cells from the placenta.

Why is CVS performed?
To diagnose genetic disorders and chromosomal abnormalities in the fetus.

When is CVS typically performed?
Between 10 and 12 weeks of pregnancy.

How is CVS performed?
Through the abdomen or cervix with a needle guided by ultrasound.

What are the risks of CVS?
Miscarriage, infection, and bleeding.

Is CVS painful?
May cause mild discomfort or cramping.

How long does CVS take?
About 30 minutes to an hour.

When are CVS results available?
Usually within 1-2 weeks.

Is CVS more accurate than other prenatal tests?
Generally more accurate than non-invasive screening tests.

Can CVS detect all genetic disorders?
No, it can only detect certain chromosomal and genetic abnormalities.