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Chorionic villus sampling

Chorionic villus sampling (CVS) is a procedure offered during pregnancy to check whether the baby has a genetic or chromosomal condition like Down’s syndrome, Edwards’ syndrome, or Patau’s syndrome. The test involves removing a small sample of cells from the placenta, an organ that links the mother’s blood supply with the unborn. 

When CVS offered

Chorionic villus sampling is not a routine test during pregnancies; the doctor may offer them only if there are high chances of your baby developing any genetic or chromosomal conditions. Due to:

  • An antenatal screening test suggests that your baby might have conditions like Down’s syndrome, Edwards’ syndrome, or Patau’s syndrome.
  • Your previous child has a genetic condition. 
  • You have family members or a history of genetic conditions.

Knowing that you shouldn’t consider CVS if you didn’t suggest one is crucial. 

Chorionic villus sampling procedure

Doctors suggest CVS usually between the 11th and 14th week of the pregnancy, but it can also be performed late if required. There are two methods for removing a small sample of cells from the placenta

When CVS offered
  • Transabdominal CVS: A needle through the abdomen (a standard method of practicing the procedure)
  • Transcervical CVS: A small forceps or tube through the cervix (neck of the womb)

The test takes only 10 minutes, and the entire procedure might be more uncomfortable than painful. Some might experience cramps similar to period pains. 

Chorionic villus sampling complications

Before deciding to have CVS, the doctor will discuss the possible complications with you. There are 1 in 100 chance of miscarriage after chorionic villus sampling complications. 

You might also develop an infection or undergo CVS if it’s unsuccessful the first time. 

Reviewed by – Dr. Priyanka, MBBS MD Microbiology
Page last reviewed: 16 JULY 2022