Chorionic villus biopsy

Chorionic villus sampling (CVS), also known as chorionic villus biopsy, is a form of prenatal diagnosis to determine chromosomal or genetic disorders in the fetus. It entails sampling of the chorionic villus (placental tissue) and testing it for chromosomal abnormalities, usually with the aim of early detection of conditions such as Down syndrome.

Procedure

The procedure is typically performed in the first trimester, between 10 and 13 weeks of gestation. It can be done either transabdominally or transcervically. In the transabdominal approach, a needle is inserted through the mother's abdomen and into the uterus under ultrasound guidance. In the transcervical approach, a thin tube is inserted through the cervix to reach the placenta. The choice of method depends on the location of the placenta, the physician's experience, and the patient's medical history.

Risks and Complications

While CVS is considered a safe procedure, it carries a small risk of miscarriage. Other potential complications include infection, bleeding, and Rh sensitization. It is therefore recommended that the procedure be performed by a trained professional in a setting where emergency care is readily available.

Benefits

The primary benefit of CVS is the early detection of genetic disorders, which allows for early decision-making and planning. Unlike amniocentesis, which can only be performed later in pregnancy, CVS can provide early diagnosis.

Limitations

While CVS can detect many chromosomal abnormalities, it cannot detect all types of genetic disorders. It also cannot detect neural tube defects. For these reasons, it is often used in conjunction with other tests.

See Also

• Amniocentesis
• Prenatal diagnosis
• Genetic testing