Chorionic Villus Sampling (CVS): Overview
Chorionic villus sampling (CVS) is a first-trimester procedure used for the prenatal diagnosis of fetal chromosomal and genetic disorders. It is usually performed between 11 and 13 weeks. CVS may be performed by two approaches. In many cases, the patient is positioned for a gynecologic examination, a speculum is inserted, and a thin catheter is guided through the cervix under ultrasound guidance to obtain a small sample of placental tissue. In some cases, a fine needle is advanced through the abdominal wall into the uterus and placenta under ultrasound guidance. With either approach, a small tissue sample is sent to the laboratory for chromosomal analysis, molecular testing for selected genetic disorders, or enzymatic testing when indicated.
CVS may be considered for abnormal first-trimester screening results, increased nuchal translucency, a known inherited condition in the family, and selected multiple pregnancies. It may also be used in specific IVF pregnancies after preimplantation genetic testing when confirmatory prenatal diagnosis is indicated.
How is the assessment planned?
Each procedure and follow-up plan is individualized by considering gestational age, the mother’s medical history, previous pregnancies, current ultrasound findings and any available screening results together.